US3581714A - Chemical treating system for steam boilers - Google Patents

Abstract

For chemical treatment of water in steam boilers, a separate chamber is provided for makeup water in a deaerating heater; and return condensate and makeup water are fed into the boiler in accordance with their relative water pressures at a junction, chemical feed solution is fed to the boiler strictly in proportion to the feed of makeup water without regard to the feed of return condensate. This is preferably accomplished by a chemical feed pump which has two coaxial cylinders and pistons in these cylinders connected to opposite ends of the same piston rod, providing four cylinder spaces. Two of these cylinder spaces acting in the same direction are subjected to regulated feed water pressure for the pressure stroke of the chemical feed pump, one is subjected to regulated feed water pressure for the suction stroke, and the fourth is the chemical pumping chamber.

Description

United States Patent [72] Inventor Frank J. Smith 7352 Limekiln Pike, Philadelphia, Pa. 19138 [21] Appl. No. 877.207 [22] Filed Nov. 17, 1969 [45] Patented June 1, 1971 [54] CHEMICAL TREATING SYSTEM FOR STEAM BOILERS 14 Claims, 4 Drawing Figs.

[52] 11.8. CI 122/1, 122/401 [51] Int. Cl F22b 37/48 [50] Field oi Search 122/1, 379, 401

[56] References Cited UNlTED STATES PATENTS 1,655,033 1/1928 Yoder 122/1 1,786,113 1211930 Henszey 122/1 1,895,635 H1933 McDonald 2,312,570 3/1943 Meier Primary Examiner-Kenneth W. Sprague Atturney-Jackson, Jackson & Chovanes 122/ l X l22/40l ABSTRACT: For chemical treatment of water in steam boilers, a separate chamber is provided for makeup water in a deaerating heater; and return condensate and makeup water are fed into the boiler in accordance with their relative water pressures at a junction, chemical feed solution is fed to the boiler strictly in proportion to the feed of makeup water without regard to the feed of return condensate. This is preferably accomplished by a chemical feed pump which has two coaxial cylinders and pistons in these cylinders connected to opposite ends of the same piston rod, providing four cylinder spaces Two of these cylinder spaces acting in the same direction are subjected to regulated feed water pressure for the pressure stroke of the chemical feed pump, one is subjected to regulated feed water pressure for the suction stroke, and the fourth is the chemical pumping chamber.

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INVENTOR FRANK J. SMITH a g g duaQmw AT 'NEY PATENTEU JUN 11911 31581714 SHEET 3 [IF 3 INVENTOR FRANK J. SMITH BY Q I ATTORNEY CHEMICAL TREATING SYSTEM FOR STEAM BOILERS DISCLOSURE OF INVENTION This invention relates to steam boiler systems, especially to the equipment and methods for the introduction to a boiler or boilers of particular quantities of chemical treating solutions for scale prevention proportionally to the introduction of deaerated boiler makeup water containing known quantities of scale forming salts and has for an object the provisions for improvements in this art.

The present state of the art is deficient in diverse particulars, the most detrimental being:

I. The inability of existing deaerating equipment to maintain separation of the deaerated makeup water and the deaerated condensate. Conventional deaerators, by permitting the deaerated makeup water to flow downwardly into and mix with the large volume of deaerated condensate in the storage tank, preclude the effective control of the proportioning of chemicals to the varying flows of the makeup water. This can best be appreciated by knowing that many deaerators operate with a minute" storage: one purpose being to have sufficient excess of water available in order that the steam generating equipment supplied, may be operated for 10 minutes or more in the event of an interruption in the flow of makeup water to the deaerating heater; another purpose being to provide ample storage space for intermittent varying amounts of returning condensate so that no part of this condensate would have to be dumped to the sewer as would be necessary with a deaerating unit of small storage volume.

It is obvious that a close approach to synchronism of introduction into a boiler of varying proportional flows of boiler water chemicals and varying proportional flows of boiler makeup water is an impossibility if the makeup water, after being deaerated, is discharged into a deaerating heater of conventional design with a large storage tank instead of being pumped into the boiler immediately, for then the importance of the timing of the proportional relationship is lost.

Prior to the use in boiler water treatment, of such chelating agents as EDTA (ethylenediaminetetraacetic acid), the need for coordinated introduction of boiler chemical treatment with the influent containing scale forming salts did not exist. The chemicals used, and in use, other than chelating agents, are not injurious to metals in general; whereas these agents, in' the absence of calcium or magnesium salts, will attack the metal of the boiler. However, since the results obtained by the use of chelating agents in conjunction with certain of the other chemicals is so far superior to the results obtained by the use of chemicals without chelating agents, their use has become a requisite in many cases where scale formation in boilers cannot be tolerated. Therefore, in view of the potential boiler damage by haphazard use of chelating agents, the importance of the introduction of the metal salts calcium and/or magnesium for reaction with the introduced chelating agents within a brief interval of time cannot be overstressed.

2. The inability of most chemical feed pumps to perform in accordance with the claims put forth for them. The field of the chemical feed pump is dominated by the electric motor, reduction gear driven pump of either the plunger or diaphragm type. Claims that these units are proportioning, metering,and adjustable are widely usedfor sales purposes, but the inherent limitations of these units belie the loosely applied terms "proportioning" and metering with the result that these terms have little value. The proportioning and metering of chemicals to a boiler in respect to varying quantities of hardness being introduced to the boiler is an impossibility with any of these pumps per se, and the so-called adjustmentsare made by the operation of some form of mechanical device not related to any proportioning method as incorporated in this invention;

3. The inability of existing systems to introduce proportional amounts of chemicals into the boiler just prior to the introduction of the amounts of makeup water hardness on which the proportional amounts of the introduced chemicals was based.

Conventional boiler systems usually have only one deaerating heater to take care of a number of boilers. If the load on these units consists of widely fluctuating makeup water and widely fluctuating returns of condensate, then the attempt to proportion the chemicals to each separate boiler based on the flow rate of makeup water to the single deaerating heater used by all the boilers can only produce poor results. This is manifest by the widespread need for acid cleaning or mechanical turbining of scale deposits from boiler drums and tubes after reasonable lengths of use, during which time chemical treatment, based on the most advanced knowledge available, had been supplied. Prevention of scale deposition by chemical reaction when the scale forming salts are in the dissolved state is not nearly as difflcult as removal of the scale after deposition on tubes and shell plate surfaces. When in solution, the reaction is rapid due to the ease of intimate mixing, but once the scale is in the form of a concrete layer on the metal surfaces, the opportunity to encircle the dissolved salts is lost. On this basis, scale deposition can only be prevented, or greatly retarded, by a system that can provide the introduction of correct amounts of chemicals into the boiler at approximately the moment of entrance to the boiler of the known quantity of scale forming salts. Since the quantity of scale forming salts in the makeupwater is easily determined, and since the quantity of chemicals needed to combine with these salts is under control, the problem resolves itself into one of timing ofintroduc' tion ofthe two different solutions into the boiler. As is evident, the method outlined in this invention is a distinct improvement for accomplishing this result.

One of the particular objects of this invention for systems having condensate returns, is the improvement in the design of a deaerating heater and its attached deaerated water storage tank by the addition of internal components comprising an isolating compartment in the deaerating top section, and, in the condensate storage tank, special conveying and mixing compartments in the form of two separate, axially concentric pipes of different diameters, slightly telescoped as a means to prevent the makeup water containing scale forming salts from entering and mixing with the main body of scale free condensate but to permit deaerated condensate or deaerated makeup water separately, ormixed in any proportion in the lower of the two concentric pipes, to flow to the boiler feed pump by way of the boiler water feed suction pipe connected to the storage tank. It is important that the transit area between the pipes be equal, at least, to the internal area of the suction pipe. The amount of telescoping of the concentric sections of the two transfer pipes is not important since the determination of the relative quantity of condensate flow to the quantity of makeup water flow depends primarily on the relative pressures of the two separate fluids at their junction within the lower concentric pipe. In a properly designed return system having normal flow of condensate to a deaerating heater with a storage tank of ample capacity, operational stability is readily maintained, and the flow of deaerated makeup water to the boiler feed pump is proportional to the chemical feed supply to the boiler regardless of the volume of flow of the condensate that is mixing with the makeup water.

Another object of this invention is the novel design of reciprocating chemical solution feed pump that utilizes the energy of the boiler feed water pump effluent to actuate the pistons of the chemical solution pump thereby increasing the pressure in the chemical feed portion of the pump to overcome the boiler pressure plus the friction in the piping and valves, in order to provide flow of chemical solution to the boiler when the pump pistons move in the compression stroke ofthe pumping cycle.

Another object of the invention relates to the novel means and methods to control the flow rate of the boiler feed water actuating the new type of chemical pump of pumps in proportion to the flow rate of the makeup water being introduced to the makeup section of the deaerating heater, and, additionally, regardless of the number of boilers involved, to control the flow rate of chemical solution to each particular boiler in proportion to the separate feed water flow rate to said particular boiler.

The above and other objects of this invention, as well as various novel features and advantages will be evident from the following descriptions of the embodiments, reference being made to the accompanying drawings thereof, wherein:

FIG. 1 is a schematic view of the invention with the novel features; namely, an improved design of deaerating heater and its storage tank with the feature for isolation of the makeup water containing scale fonning salts from the salt free condensate in the storage tank prior to the flow of condensate into the lower boiler feed pump suction piping compartment; a new design of reciprocating chemical solution pump with controls and accessories; and means for controlling flow of chemical feed to each boiler or boilers separately in desired proportion to the flow of makeup water to each boiler or boilers separately, and totally in proportion to the flow of makeup water to the deaerating heater. The view shown in FIG. 1 is an application for a single boiler, but with indicated outlets and connections for additional boilers. Each additional boiler requires a cam controller, solenoid valves, a chemical pump, a chemical pump solution tank, pressure control switches, air operated control valves, air operated diaphragm control pilot valves, gauges, check valves, etc. The use of a separate chemical tank, although not required but considered desirable, is based on the flexibility such an installation affords in adjusting the amount of chemical concentration in the separate tanks to compensate for any possible variations in operating characteristics of the different chemical pumping systems as determined by a comparison of the actuate excess of chemicals present in the boiler waters in relation to that desired.

FIG. 2 is a sectional view of the new design of pump. This unit comprises a pair of coaxial, cylindrical chambers of like or unlike diametrical measurements, each chamber housing a piston attached to a piston rod extending between the two chambers. Fluid pressure is introduced to one side of each piston thereby moving the piston assembly and creating high pressure on the opposite side of one of the pistons. Movement of the piston assembly in the reverse direction is accomplished by venting the actuating fluid pressure mentioned, usually to the deaerating heater, and by the introduction of fluid pressure to the opposite side of one of the pistons. Since the motive power obtained from the boiler feed pump is always at a higher pressure than the reactive pressure in the boiler, the total force on the two pistons is more than twice the boiler reactive pressure. To compensate for the problems arising from the extreme differences in the pressures, the following alternatives are available for use in improving the pump operations: (1) reduction in boiler water pump pressure to the chemical solution pump; (2) reduction in size of one cylinder and its piston; (3) a combination of these two mentioned choices. Alternative I) has the following important features: the first being that by reducing the motive power in both chambers, the strain on the packing of the piston rod and the pistons is reduced; and secondly, that a greater degree of control of the operation of the pump is obtained by the latitude afforded by the wide range of motive pressure adjustment.

FIG. 3 is a schematic view of a system consisting of a single boiler with, optionally, a simple on-off boiler feed pump control, a single deaerating heater of the new design, a conventional electric motor driven chemical feed pump of plunger, diaphragm, or other design, with a chemical tank; to which a modification of the novel system for the introduction of deaerated boiler makeup water is applied. Since the air operated diaphragm control pilot valve on the deaerating heater controls not only the air operated makeup valve on the piping to the deaerating heater but also the air operated chemical solution flow control valve in the piping to the boiler, no control pilot is required on the boiler.

Fig. 4 is a schematic view of the invention for a system consisting of two or more steam boilers supplied from a single deaerating heater having the new design as mentioned above; a single chemical solution tank with an electric motor driven chemical feed pump of plunger, diaphragm, or other design; air operated diaphragm control pilots on the deaerating heater and on each boiler; air operated diaphragm valves to control the total flow of the chemical solution in proportional to the makeup water flow to the deaerating heater and to control the flow of the chemical solution to the separate boilers in proportion to the flow of boiler water makeup to said boilers.

Referring to FIG. I, boiler makeup water supplied from a conventional pressure source flows through pipe 1, through recording water meter 2, to and through air operated control valve 3 to spray pipe 4 located within isolated chamber 5 of deaerating heater top 6. Chamber 5 except for an opening for passage of deaerating steam is isolated from the rest of space 7 in the deaerating heater top 6 by vertical partition 8 and from space 9 in the top of deaerating storage tank 10 by horizontal member 11 to which vertical pipe 12, projecting downwardly in storage tank 10 is attached. Pipe 12 is the upper of two axially concentric pipes used as a means to convey the deaerated makeup water to the lowest of the two axially concentric pipes 13 and thence through the boiler feed pump suction pipe 14 attached to deaerating heater storage tank 10, to boiler feed pump 15. The internal diameter of pipe 12 should be equal to the internal diameter of the suction pipe 14, and the ct area of the annular opening between the two axially concentric pipes of different diameters l2 and 13 should be equal to the crosssectional area of the suction pipe 14.

Steam condensate is returned under pressure from remote condensing equipment not shown, through pipe 16 into spray 17 located in the deaerating space 7, sprayed over trickle trays, ceramic or metal cylinders, or other devices used in space 7 but not shown, to expose the condensate to the surrounding steam, accumulates at the bottom section 18 of storage tank 10, whence it flows between the two concentric pipes 12 and I3, mixes with the makeup water flowing downwardly from pipe 12 and flows downwardly through pipe 14 to boiler feed pump 15 as needed. For simplicity of illustration, conventional steam supply and venting equipment of the deaerating heater top 6 has been omitted.

Attached to storage tank head 19 are pipes 20 and 21 to which are attached water level gauge column 22 and air operated diaphragm control pilot 23. Attached to control pilot 23 is air supply pipe 24 connected to an external source of air at a desired pressure. Control pilot 23 supplies air at varying pressure through pipe 25 in accordance with varying static pressure on the diaphragm of said control pilot 23 to control the operation of diaphragm control valve 3 thereby maintaining a desired water level in storage tank 10. Control pilot 23 also supplies air to air operated control valve 26, and to pressure control valve 27 used to make or break an electrical circuit to be described later.

Attached to steam drum 29 of boiler 30 are pipes 31 and 32 to which are attached water level gauge column 33 and air operated diaphragm control pilot 34. Attached to control pilot 34 is air supply pipe 35 connected to an external source of air at a desired pressure. Control pilot 34 supplies air at varying pressure through pipe 36 in accordance with varying static pressure on the diaphragm of control pilot 34 to control the operation of diaphragm control valve 37 to maintain a desired water level in drum 29. Control pilot 34 also supplies air to control the operation of diaphragm valve 38 and pressure control 28. Boiler water is supplied from boiler feed pump 15 through boiler feed piping 40, through water recording meter 60, through control valve 37 to boiler drum 29.

Additional boilers may be connected for feed water supply as shown at D by pipe 40 from pipe 40 through meter 60 and control valve 37; for chemical feed pump actuating pressure from pipe 42 through control valve 38' shown at E, and electrical connections 83 and 84 shown at F.

Boiler feed pump 15 also supplies motive power to chemical solution pump 41 by means of regulated high pressure water from piping 40 through piping 42, through pressure reducing valve 43, air operated control valve 26, air operated control valve 38, solenoid valve 39 and thence to pipes 44 and 45 con nected to reciprocating pump 41. Water pressure gauges 46, 47, 48, and 49 connected to piping 42 serve to indicate water pressure variations that reveal proper or improper functioning of the controls. The transit of fluid from the space below the upper piston of pump 41 to the deaerating heater is by means of flow through pipe 50, pipe 51, solenoid valve 52, and pipe 53.

The transit of fluid from the spaces above both pistons of pump 41 to the deaerating heater 10 is by means of flow through pipes 44 and 45 simultaneously, then through pipe 54, solenoid valve 55, and pipe 53.

Boiler feed pump also supplies motive power to chemical solution pump 41 by means of pipe 42, pipe 56, through solenoid valve 57, and pipe 50. Water pressure gauge 62 indicates by variations of readings when flow of chemical solution is taking place from pump 41 to boiler drum 29 by way of pipe 58.

Flow of chemical solution from tank 64 into pump 41 when lower piston of pump 41 creates a suction, is by means of piping 65, check valve 66, and pipe 58. Cam program controller 68, when supplied with electrical current, controls the timing of electrical energy to the coils of solenoid valves 39, 52, 57 and 55.

When switches of pressure controls 27 and 28 are both closed, current from L1 passes through line 80, line 81, and line 82 to control 68. Cam motor 69, connected to line 82 b line 70 and connected to L2 by line 71 operates continuously when the switches 27 and 28 are closed. Cam A controls the operation of solenoid valves 39 and 52; cam B controls the operation of solenoid valves 57 and 55. Cam switch 72 of cam A is supplied from line 82 by line 73. When switch 72 closes, current from line 82 flows to coil 74 of solenoid valve 39 by line 75 and flows to L2 by line 76; current also flows to coil 77 of solenoid valve 52 by line 78 and flows to L2 by line 79. Cam switch 85 of the cam B is supplied current from line 82 by line 86. When switch 85 closes, current flows to coil 87 of solenoid valve 57 by line 88 and flows to L2 by line 89; current also flows to coil 90 of solenoid valve 55 by line 91 and flows to L2 by line 92.

Electrical switches of pressure controls 27 and 28 close when pressure in pipes and 36 is lowered to predetermined points.

FIG. 2 is an axially sectional view of pump 41. Removably bolted to the upper surfaces of central support member 210 by its flange 211 is upper cylinder 212 with its head 213; bolted to the lower surface of central support member 210 by its removable flange 214 is lower cylinder 215 with its head 216; within upper cylinder pump chamber 217 is upper piston 218 secured to piston rod 219 by nut 220; with lower cylinder pump chamber 221 is lower piston 222 secured to piston rod 219 by nut 223; connected to the upper cylinder 212 with passageway into chamber 217 and above the upper side of piston 218 at its uppermost travel is pipe 44; connected to the lower cylinder 215 with passageway into chamber 221 and above the upper side of piston 222 at its uppermost travel is pipe 45; connected to the upper cylinder 212 with passageway into chamber 217 and below the lower side of piston 218 at its lowermost travel is pipe 50; and connected to the lower cylinder head 216 with passageway into chamber 221 and below the lower side of piston 222 at its lowermost travel is pipe 58. Pipe 58 instead of being connected to the lower cylinder head 216 as shown in FIG. 2, may be connected by lower cylinder 215 of pump 41 as shown in FIG. 1.

Support member 210 has a suitable opening for reciprocating movement of piston rod 219, and has also a suitable recess for piston packing ring 226; piston packing ring 224 is installed in a suitable recess of piston 218; and piston packing ring 225 is installed in a suitable recess of piston 222.

DESCRIPTION OF OPERATION OF FIG. 1

To simplify the description of the functions of the various components of FIG. 1 in relation to each other during a varying range of steam demands and varying makeup water demands, it is deemed advisable to divide the explanation into three sections: (l) the functions of the components during the extreme condition when all condensate from process equipment and/or heating equipment is being returned to the deaerating heater and no makeup water is required to the system; (2) the functions of the components during fluctuating system demands to processes during which operations condensate is lost to the system, as well as fluctuating steam demands to equipment from which the condensate is returned to the deaerating heater; and v(3) the functions of the components during the other extreme when there is no condensate being returned to the deaerating heater and the entire volume of the makeup water is lost to the system by use in processes that return no condensate.

Based on the hypothetical arrangement of section (1), that is, when the rate of the evaporation of the boiler water in drum 29 of boiler 30 is equal to the flow of condensate returning to the deaerating heater 10, and this condensate in turn is being returned to the boiler by pump 15, through pipe 40, recording meter 60 and flow control valve 37, a state of equilibrium exists whereby the water levels in both the boiler drum 29 and in the deaerating storage tank 10 are stable. Deaerating heater level control pilot 23 maintains sufficient air pressure to valves 3 and 26 to keep them closed, and to pressure control switch 27 to keep its electrical circuit open; boiler level control pilot 34 supplies regulated air to valves 37 and 38 and to pressure control 28, permitting valve 37 to open sufficiently to maintain a relatively constant water level in drum 29, and similarly to valve 38 to open to a proportional degree.

Pressure control 28 permits its electrical circuit to close but inasmuch as the electrical circuit of pressure control 27 is open, and since this circuit is in series with the circuit of 28, no current can flow to cam controller 68. Since valve 26 is closed, no fluid pressure can pass to pump 41.

It is now established that no chemical solution can be pumped into the boiler in the absence of scale forming salts to be reacted with, obviating the possibility of damage to the boiler metal by chelating agents. Since chelating agents are broad spectrum with regard to almost all metals, a potential hazard exists when these chemicals are present in the boiler in the absence of calcium of magnesium.

(Section 2) Assuming that the state of equilibrium of the arrangement under section 1 as described above is disturbed by the activation of process equipment from which no condensate is returned to the deaerating heater from steam supplied to said process equipment, the water level in the deaerating heater storage tank 10 will fall, the pressure on the diaphragm of control pilot 23 will change and this control will bleed off air pressure in pipe 25 to permit valves 3 and 26 to open under controlled rates. This reduction in air pressure in pipe 25 also permits the electric circuit of pressure switch 27 to close. Water now flows through pipe 1, is sprayed into the isolated section 5 from spray pipe 4, and flows down in pipe 12 becoming a dominant part of the total flow through suction pipes 13 and 14 and to pump 15 in retarding the flow of condensate from the lower part 18 of tank 10 into suction pipe 14. In so doing, the volume of flow of returning condensate, being greater than the volume being withdrawn, will raise the water level in the tank.

Current now flows to motor 69 of cam controller 68 through line and thence to ground by line 71, starting rotation of cams A and B. Assuming for clarity of sequence that switch 72 of cam A is initially closed, solenoid valves 39 and 52 now open, permitting fluid flow from pipe 40 to pass through reducing valve 43, valve 26, valve 38, solenoid valve 39 and into pump 41 by way of pipes 40, 42, 44 and 45. The pistons in pump 41 then travel downwardly forcing fluid from the upper cylinder through solenoid valve 52 to deaerating heater storage tank 10 by way of pipes 50, 51 and S3. Fluid in the lower cylinder of pump 41 is forced into boiler drum 29 by way of check valve 61 and pipe 58. After a set time interval switch 72 of cam A opens, closing solenoids 39 and 52 and switch 85 of cam B closes, opening solenoid valves 55 and 57. Fluid pressure now flows from pipe 42, through pipe 56, through valve 57, through pipe 50 into the lower portion of pump 41, forcing the pistons upwardly. The fluid in the top of the upper cylinder of pump 41 is forced through pipes 44 and 54, valve 55, and pipe 53 to deaerating heater tank 10. During this upward movement of the pistons of pump 41, a lowering of pressure in the lower cylinder of pump 41 occurs, permitting atmospheric pressure on the chemical solution in tank 64 to force this solution into the lower cylinder of pump 41, by way of pipe 65 and pipe 58, through check valve 66. Again, after a set time interval, switch 85 of cam B opens, closing solenoid valves 55 and 57. Switch 72 of cam A now closes, completing the cycle of operation of pump 41. Movement of the pistons of pump 41 depends on the pressure of fluid supplied to the pump through control valves 26 and 38. If no makeup is being added to the deaerator, valve 26 remains closed and no chemical solution can be pumped to the boiler. As the volume of makeup water to the deaerating heater is increased, the control pilot connected to the boiler drum to which this water is being pumped will activate the control valve to operate the chemical feed pump for this particular boiler proportionally to the flow of makeup water to the boiler drum. For instance, if the makeup boiler water is being pumped to drum 29 of boiler 30, then control valve 38 will permit the pump 41 to pump chemical solution to drum 29. If the makeup boiler water is not being pumped to drum 29, then the other boiler and its system, not shown, will permit its system to be acted on by fluid through control valve 38 shown at E.

It is now evident that only when makeup water is being permitted to flow to the deaerating heater is it possible to pump chemicals to any boiler supplied with water from the deaerat ing heater; that only the boiler receiving this makeup water will proportionally actuate its separate chemical feed pump to the flow of this water, and that in the event of more than one boiler receiving makeup water simultaneously, each boiler will actuate its own pumping system proportionally to the amount of boiler makeup water being fed to it.

(Section 3) When no condensate returns are flowing to the deaerating heater, the operations of the boiler, or boilers is as described under section 2.

DESCRIPTION OF OPERATION OF FIGURE 3 As previously mentioned, FIG. 3 shows a system consisting of a single boiler with a simple on-off" boiler feed water pump control (not shown), a continuously running motor driven chemical feed pump with its chemical tank; and a deaerating storage tank system as described for FIG. 1.

The three conditions under which this system operates is (1) 100 percent return of condensate, requiring no makeup water; (2) a varying percentage of condensate returns with complementary percentages of makeup water to supply what is lost to process; and (3) I percent makeup water.

As in FIG. 1, operation under condition (1) is that ofa state of equililbrium whereby the water levels in boiler drum 29 and in deaerating storage tank are stable. Control pilot 23 keeps control valves 3 and 93 closed and therefore no makeup water can flow to deaerating heater top 6, and no chemical solution can flow to boiler drum 29.

During the operation under condition (2), varying amounts of makeup water flow to deaerator storage tank 10 as control pilot 23 permits valve 3 to open, and proportionate amounts of chemical solutions are permitted to flow to drum 29 as control pilot 23 permits valve 93 to open proportionally to the opening of valve 3. During operation under condition (3), when no condensate is being returned to the deaerating heater, the operation of the chemical treatment equipment is identical to that under operation (2 DESCRIPTION OF OPERATION OF FIGURE 4 The operation of equipment shown in FIG. 4 differs from that of FIG. 1 in that a chemical solution pump consisting of a conventional electric motor driven geared plunger or diaphragm type is substituted for the novel design of reciprocating unit of FIG. 1. The operation of the deaerating heater and the boilers of FIG. 4 is identical to that of FIG. 1, but the method of controlling the flow of chemical solution proportionally to the flow of makeup water to each boiler differs from the method outlined for FIG. 1. Each boiler of FIG. 1 has its own chemical feed pump and tank; and the operation of the separate reciprocating chemical feed pumps is regulated to supply chemical solution to each boiler proportionally to the flow of makeup water to each boiler proportionally to the flow of makeup water to each boiler by the control of movement of the pump pistons. The control is effected by varying the amount of high pressure water that actuates the pumps. No chemical solution passes through the valves that control the movements of these pumps in FIG. 1. In FIG. 4, however, the valves are arranged to control the flow of the chemical solutions to each boiler proportionally to the flow of makeup water to each boiler by restricting the flow of the chemical solution that passes through the bodies of these valves.

The three conditions under which this system operates is (I) percent return of condensate, requiring no makeup water; (2) a varying percentage of condensate returns with complementary percentages of makeup water to supply water that is lost to process; and (3) 100 percent makeup water.

Operation under condition l) is that of a state of equilibrium whereby the water levels in the boiler drum or drums and in the deaerating storage tank 10 are stable. Control pilot 23 keeps control valves 3 and 96 closed and therefore no makeup water can flow to deaerating heater top 6, and no chemical solution can flow through valve 96.

During the operation under condition (2), varying amounts of makeup water flow through the isolated deaeration section and transit piping to the boiler feed pump as control pilot 23 permits valve 3 to open, and proportionate amounts of chemical solutions are permitted to flow to drum 29 and/or to drum 29' as valve 96 is opened by controller 23, and as valves 98 and 98' are opened by control pilots 34 and 34 respectively.

CONCLUSION The isolation compartment of this invention may take forms other than shown in FIGS. 1, 3 and 4. It is not critical in the invention whether this special compartment consists of a vertical cylinder open at both ends, of smaller diameter than and located within the top deaerating section, and extending almost to the upper head of the deaerating section in order to provide passage for steam at the upper end, and extending almost to the lower section of the storage tank over the suction pipe opening in order to provide passage for water at the lower end; or whether it consists of a vertical cylinder of smaller diameter than and located within the top deaerating section, and extending almost to the upper head of this section but with a bottom member having an opening for passage of fluid into a conveying means consisting of piping attached to this lower member projecting downwardly axially to the opening of the boiler feed water suction pipe. Again, the internal diameter of this pipe must be equal to the internal diameter of the boiler feed water suction pipe, and also, a peripheral opening equal to the cross-sectional area of the suction pipe must be provided for passage of fluid in either direction in the lower portion of the storage tank.

The size of the isolated makeup water deaerating compartment and the size of the condensate deaerating compartment are independently determined by the capabilities of the deaerating equipment used in these separate spaces to provide a specified end result of deaeration.

It should be recognized that it is not critical in the invention whether, instead of the two concentric pipes 12 and 13 shown in FIGS. 1, 2 and 4 in the deaerating heater storage tank for the transit of deaerated makeup water, the following means are used: (l) a single pipe of internal diameter equal to the internal diameter of the boiler feed pump suction piping, attached to and projecting downwardly from the bottom of the isolating chamber, axially located in reference to the boiler feed pump suction piping opening, and spaced sufficiently above the bottom of the storage tank to provide a peripheral opening equal to the internal cross-sectional area of the boiler feed pump suction piping; (2) two pipes of the same internal diameter each equal to the internal diameter of the boiler feed suction piping, axially located in reference to the boiler suction piping, the top one attached to the lower member of the isolating chamber and the other attached to the inner surface of the storage tank 10 at the suction pipe opening with a peripheral opening equal in area to the area of the internal diameter of the piping; or a reversal of the two concentric pipes as shown, whereby the larger diameter pipe now attached to the member ll of the isolating chamber and the smaller pipe attached to the storage tank 10 at the suction pipe opening. Again, the transit area for flow of condensate into the space above the opening of suction pipe 14 must be equal to the cross-sectional area of the suction pipe.

in FIGS. 1, 3 and 4 the normal equipment of deaerating heaters such as steam piping and itscontrol for maintaining desired steam pressure in the deaerator and tank; spray nozzles, trickle trays, vent condenser, vent piping and the overflow piping and controls have been omitted for clarity of presentation.

The use of two or more sets of concentric downflow pipes from an isolating compartment whether to supply a simple installation of a single pump or to supply more than one pump, does not constitute an improvement on this invention.

The use of a deaerating heater with two separate tops, one of which would be equipped with an isolating chamber and concentric transfer piping does not constitute an improvement on this invention.

Since this system will function without the pressure switches 27 and 28, these units are included only as a safety measure to prevent operation of the pump 41 when the flow control valves to the pump 41 are also shut off. Therefore, the omission of these desirable controls does not constitute an improvement on this invention.

In FIG. 1 the following outlets and connection are illustrated as means to connect to a second boiler and its related equipment; at D, boiler water flow control valve 37' and water meter 60" are connected to boiler feed waterpipe 40 by pipe 40; at E, chemical pump flow control valve 38' is connected to pipe 42 by pipe 42'; and at F, open electrical line connections 83 and 84 are illustrated, to be connected to pressure switch 28 and cam controller 68 of a second unit, not shown;

Special mention is made concerning the flow control valves: valves 3, 37 and 37 have bodies designed for large flow of fluid; valves 26, 38, 38', 96 and 98 are valves in the miniature class for very small fluid flow.

Since there are many flow characteristics of the control valves available from any manufacturer of this equipment, such as percentage, ported," linear needle, etc. it must be understood that good results can only be obtained by the use of miniature valves designed with the same characteristics as that of the larger valves with which they are to function proportionally, and that the application of the same air pressure to the actuators of the valves will place the valve stems in positions that produce proportional flows.

For instance, a percentage design, when opened to 40 percent of the maximum nominal valve travel has a percentage flow of only 10 percent whereas a linear" design at 40 percent of the maximum nominal valve travel has a percentage flow of 40 percent; It is evident, that to achieve proportional flows, the use of two valves with the same characteristics is a strict requirement.

it should be understood that the control system presently shown is only representational and that the same results may be accomplished by other designs of fluidic or electrical water level controllers and/or other designs of fluidic or electrical flow control valves in various operational configurations.

It is understood that the application of isolating means for deaeration and storage of condensate and deaeration and transit of makeup water in any other form of deaerating and storage apparatus does not constitute an improvement on this invention.

it is understood that the substitution of the transit piping shown in FIGS. 1, 3 and 4 projecting downwardly from the isolation chamber by any other conduit of cross sectional shape other than the cylindrical form shown does not constitute an improvement on this invention.

It will be evident that if desired, the mechanism of the invention can be constructed, using two deaerating heaters instead of a single deaerating heater, one deaerating heater operating on. return condensate and the other on makeup water.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art to obtain all or part of the benefits of my invention without copying the structure and method shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope ofmy claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A chemical treatment system for steam boilers, comprising in combination, a deaerating heater having both a deaerating chamber for deaeration of return condensate free from scale forming salts and with a communicating passageway to the chamber of the storage'tank for deaerated condensate, and a separate deaeration chamber within the heater for deaeration of makeup. water containing scale forming salts with a separate conduit passageway for storing or conveying deaerated makeup water, a feed water pump and piping connecting the discharge of the feed water pump to the boiler, suction piping connecting the feed water pump to the bottom of the deaerating heater storage tank within which tank are two branch passageways, one communicating with the deaerated condensatestorage chamber and the other communicating with the discharge opening of the makeup water conduit passageway, a chemical feed pump and discharge piping connections to the boiler from the chemical feed pump, piping connections from the chemical solution tank to the chemical pump, and means for proportioning the discharge of the chemical feed pump to the supply of deaerated makeup water containing scale forming salts to the boiler regardless of the quantity of deaerated scale free condensate being pumped to the boiler.

2. A system of claim 1, for supplying chemical treatment to a plurality of high pressure steam boilers, comprising in combination a chemical feed pump for each boiler and-means for proportioning the discharge of the chemical feed pump for each boiler to the supply to that particular boiler of deaerated makeup water containing scale forming salts regardless of the quantity of deaerated scale free condensate being pumped to that particular boiler.

3. A system of claim 1, in which the branch passageway connected to the suction piping conveying condensate free from scale forming salts surrounds the branch passageway conveying makeup water containing scale forming salts to the suction piping.

4. A system of claim 3, in which the area of the branch passageway for conveying makeup water containing scale forming salts is equal tothe internal area of the suction piping.

5. A system of claim 3, in which the peripheral area of the branch passageway for conveying condensate free from scale forming salts surrounding the branch passageway for conveying makeup water containing scale forming salts is equal to the internal area of the suction piping.

6. A system of claim 5, in which the chemical feed pump comprises two coaxial cylinders, a piston rod extending between the cylinders, packing means sealing against the piston rod between the cylinders, pistons on both ends of the piston rod, piston packing means sealing against the cylinders, means for regulating, and controlling the pressure and volume of high pressure water from the boiler feed pump, high pressure piping conveying said regulated and controlled high pressure water, to both cylinders on sides of the pistons acting in the same direction, for the pressure stroke and a suction activating connection from the regulated and controlled high pressure pumping connection to one of the cylinders on the other side of its piston, and having a chemical pumping suction and discharge connection to the other cylinder on the side of the piston opposite to the high pressure pumping connection.

7. A system of claim 1, in which the chemical feed pump comprises two coaxial cylinders, a piston rod extending between the cylinders, packing means sealing against the piston rod between the cylinders, pistons on both ends of the piston rod, piston packing means sealing against the cylinders, means for regulating, and controlling the pressure and volume of high pressure water from the boiler feed pump, high pressure piping conveying said regulated and controlled high pressure water, to both cylinders on sides of the pistons acting in the same direction, for the pressure stroke and a suction activating connection from the regulated and controlled high pressure pumping connection to one of the cylinders on the other side of its piston, and having a chemical pumping suction and discharge connection to the other cylinder on the side of the piston opposite to the high pressure pumping connection.

8. In a chemical treating system for steam boilers, a deaerating heater having separate means for deaerating and storing condensate free from scale forming salts and makeup water containing scale forming salts, a feed water pump and connections for supplying feed water to the boiler, suction piping from the deaerating heater to the feed water pump and connections for supplying feed water to the boiler, suction piping from the deaerating heater to the feed water pump, and means for conveying the condensate free from scale forming salts to the suction piping and separate means for conveying the deaerated makeup water containing scale forming salts to the suction piping.

9. In a chemical treatment system for steam boilers, a deaerating water heater having separate chambers for deaerating and storing return condensate and makeup water containing scale forming salts, a feed water pump and connections from the feed water pump to the boiler, and suction piping from the deaerating heater communicating with the condensate chamber and the makeup water chamber and discharging condensate and makeup water to the feed water pump in proportion to the relative water pressures of the condensate and the makeup water at theirjunction.

10. A system of claim 9, in combination with a reciprocating chemical feed pump energized by water from the feed water pump, subjected in one direction to the regulated pressure of the water from the feed water pump acting on two different areas, and subjected in the other direction to approximately the same pressure as the regulated water pressure from the boiler feed pump acting on one area.

11. In a boiler treatment system, a boiler feed pump and connections from the boiler feed pump to the boiler, a reciprocating chemical feed pump having two coaxial cylinders, a piston rod extending through and between the cylinders, packing means sealing against the piston rod between the cylinders, and opposed pistons and piston packings at opposite ends of the piston rod, connections to both cylinders from the boiler feed pump on a side of the pistons which acts in the same direction for producing a pumping stroke of the chemical feed pump, a connection from the boiler feed pump to one of the cylinders on the opposite side of the piston to that producing the pumping stroke for producing the suction stroke of the chemical feed pump and chemical feed suction and discharge connection from the other cylinder on the opposite side of the piston from that producing the pumping stroke.

12. A method of chemical treatment for steam boilers,

which comprises preheating and deaerating return condensate from a boiler, separately preheating and deaerating makeup water containing scale forming salts for the boiler, pumping to the boiler feed water which comprises a combination of condensate and makeup water depending upon the relative pressures of the condensate and makeup water at a junction, and pumping to the boiler chemical treatment solution in proportion to the feed to the boiler of makeup water containing scale forming salts without regard to the quantity of return condensate which is being fed to the boiler.

13. A method of operating a chemical treatment for a boiler using a chemical feed pump having opposed cylinders, and pistons, which comprises pumping feed water to the boiler, subjecting the chemical feed pump in both cylinders on the sides of the pistons acting in the same direction to regulated pressure from the boiler feed water on the compression stroke, subjecting the chemical feed pump in one of the cylinders to regulated boiler feed water on the side of its piston opposite to that utilized in the compression stroke to accomplish the suction stroke, and pumping chemical treatment to the boiler from the other side of the piston in the other cylinder,

14. A process of claim 13, which comprises pumping the chemical treatment solution to the boiler in proportion to makeup water containing scale forming salts fed to the boiler, without regard to the quantity of return condensate fed to the boiler.

POM) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. UUS. Dated June 1.,

Inventor(s) Frank J.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2. line 73, change the word "of" to --or Column 4, line as, change the word "proportional to proportion-m Column 4, line 26, change et to net Column 5, line 30, change the letter- "h Lo -hy- Column line 3o, insert the word current oerol'e "from"and after "supplied Column 5, l i ne 55, change the word "w l th to wjthin-- Column a), line 12, change the word "system to steem-- Column o, line 47, change the word of "to o1.

Column (5. line 75'), change the number "2 to -j-- Signed and sealed this 16th day of November 1.971..

SEAL) Attest:

mum mmmswcmznml. ROBERT GO T'PSCHALK Attestimg Officer Acting Commissioner of Patents

Claims (13)

1. 2. A system of claim 1, for supplying chemical treatment to a plurality of high pressure steam boilers, comprising in combination a chemical feed pump for each boiler and means for proportioning the discharge of the chemical feed pump for each boiler to the supply to that particular boiler of deaerated makeup water containing scale forming salts regardless of the quantity of deaerated scale free condensate being pumped to that particular boiler.
2. 3. A system of claim 1, in which the branch passageway connected to the suction piping conveying condensate free from scale forming salts surrounds the branch passageway conveying makeup water containing scale forming salts to the suction piping.
3. 4. A system of claim 3, in which the area of the branch passageway for conveying makeup water containing scale forming salts is equal to the internal area of the suction piping.
4. 5. A system of claim 3, in which the peripheral area of the branch passageway for conveying condensate free from scale forming salts surrounding the branch passageway for conveying makeup water containing scale forming salts is equal to the internal area of the suction piping.
5. 6. A system of claim 5, in which the chemical feed pump comprises two coaxial cylinders, a piston rod extending between the cylinders, packing means sealing against the piston rod between the cylinders, pistons on both ends of the piston rod, piston packing means sealing against the cylinders, means for regulating, and controlling the pressure and volume of high pressure water from the boiler feed pump, high pressure piping conveying said regulated and controlled high pressUre water, to both cylinders on sides of the pistons acting in the same direction, for the pressure stroke and a suction activating connection from the regulated and controlled high pressure pumping connection to one of the cylinders on the other side of its piston, and having a chemical pumping suction and discharge connection to the other cylinder on the side of the piston opposite to the high pressure pumping connection.
6. 7. A system of claim 1, in which the chemical feed pump comprises two coaxial cylinders, a piston rod extending between the cylinders, packing means sealing against the piston rod between the cylinders, pistons on both ends of the piston rod, piston packing means sealing against the cylinders, means for regulating, and controlling the pressure and volume of high pressure water from the boiler feed pump, high pressure piping conveying said regulated and controlled high pressure water, to both cylinders on sides of the pistons acting in the same direction, for the pressure stroke and a suction activating connection from the regulated and controlled high pressure pumping connection to one of the cylinders on the other side of its piston, and having a chemical pumping suction and discharge connection to the other cylinder on the side of the piston opposite to the high pressure pumping connection.
7. 8. In a chemical treating system for steam boilers, a deaerating heater having separate means for deaerating and storing condensate free from scale forming salts and makeup water containing scale forming salts, a feed water pump and connections for supplying feed water to the boiler, suction piping from the deaerating heater to the feed water pump and connections for supplying feed water to the boiler, suction piping from the deaerating heater to the feed water pump, and means for conveying the condensate free from scale forming salts to the suction piping and separate means for conveying the deaerated makeup water containing scale forming salts to the suction piping.
8. 9. In a chemical treatment system for steam boilers, a deaerating water heater having separate chambers for deaerating and storing return condensate and makeup water containing scale forming salts, a feed water pump and connections from the feed water pump to the boiler, and suction piping from the deaerating heater communicating with the condensate chamber and the makeup water chamber and discharging condensate and makeup water to the feed water pump in proportion to the relative water pressures of the condensate and the makeup water at their junction.
9. 10. A system of claim 9, in combination with a reciprocating chemical feed pump energized by water from the feed water pump, subjected in one direction to the regulated pressure of the water from the feed water pump acting on two different areas, and subjected in the other direction to approximately the same pressure as the regulated water pressure from the boiler feed pump acting on one area.
10. 11. In a boiler treatment system, a boiler feed pump and connections from the boiler feed pump to the boiler, a reciprocating chemical feed pump having two coaxial cylinders, a piston rod extending through and between the cylinders, packing means sealing against the piston rod between the cylinders, and opposed pistons and piston packings at opposite ends of the piston rod, connections to both cylinders from the boiler feed pump on a side of the pistons which acts in the same direction for producing a pumping stroke of the chemical feed pump, a connection from the boiler feed pump to one of the cylinders on the opposite side of the piston to that producing the pumping stroke for producing the suction stroke of the chemical feed pump and chemical feed suction and discharge connection from the other cylinder on the opposite side of the piston from that producing the pumping stroke.
11. 12. A method of chemical treatment for steam boilers, which comprises preheating and deaerating return condensate from a boiler, separately preheating and dEaerating makeup water containing scale forming salts for the boiler, pumping to the boiler feed water which comprises a combination of condensate and makeup water depending upon the relative pressures of the condensate and makeup water at a junction, and pumping to the boiler chemical treatment solution in proportion to the feed to the boiler of makeup water containing scale forming salts without regard to the quantity of return condensate which is being fed to the boiler.
12. 13. A method of operating a chemical treatment for a boiler using a chemical feed pump having opposed cylinders, and pistons, which comprises pumping feed water to the boiler, subjecting the chemical feed pump in both cylinders on the sides of the pistons acting in the same direction to regulated pressure from the boiler feed water on the compression stroke, subjecting the chemical feed pump in one of the cylinders to regulated boiler feed water on the side of its piston opposite to that utilized in the compression stroke to accomplish the suction stroke, and pumping chemical treatment to the boiler from the other side of the piston in the other cylinder.
13. 14. A process of claim 13, which comprises pumping the chemical treatment solution to the boiler in proportion to makeup water containing scale forming salts fed to the boiler, without regard to the quantity of return condensate fed to the boiler.

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