US2357445A - Vacuum deaerating receiver - Google Patents

Description

vc. l. BAKER VACUUM DEAERATING RECEIVERy Sept. 5, 1944.

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Patented Sept. 5, 1944 UNITED STATES PATENT OFFICE 2,357,445 VACUUM DEAERATING RECEIVER Charles I. Baker, West Hickory, Pa.

Application rJune 6, 1942, Serial YNo. 446,080

6 Claims. (Cl. 230-83) This invention relates to steam heating systems, and more particularly to apparatus for creatingY a vacuum or suction in the return lines and for deaerating the condensed Vsteam and makeup water.

For eicient operation steam heating systems require free circulation of both the steam and condensate to properly distribute the steam to all parts of the system. They also should have deaeration of the water in the system to free it of pipe-corroding gases that it has dissolved and entrained. To provide the desired distribution of steam it is common to produce a partial vacuum in the system in order to draw the condensate, vapors, and gases back to the receiver and to avoid the necessity of forcing the steam through the system by high boiler pressure which is noisy and puts excessive strain on the equipment. The necessity for deaeration is due to the inleakage of corrosive gases as well as the presence of such gases in makeup water. Some of ythese gases, being soluble in water, remain in it until boiled away, but a greater proportion of them are held in the water by mechanical entrainment due to the fact that the condensate, which is turbulently returning .through the piping, entraps air that is in the pipes. Although the entrained gases could escape freely by flotation if the condensate were permitted to lie dormant for a short period, most vacuum return receivers hinder flotation because they increase the turbulency of the condensate.y Y

Most vacuum receivers in use today were designed years ago when little was -known about deaeration or even the true cause of return pipe destruction. A careful study of the functioning .of such vacuum receivers will disclose that they were designed principally for withdrawing conednsate and gases from return piping to aid steam circulation but have little provision for extracting dissolved and entrained gases from the condensate. While withdrawing gases from return piping they intensely mingle gases vand lcondensate and thus load the condensate with quantities of entrained corrosive gases as the condensate is returned to the boiler. Consequently, these vacuum receivers may be charged with increasing corrosion in boilers, return piping, and return equipment. The most severe corrosion in vacuum heating systems has been found to be in the feed water piping between receiver and boiler. 'I'he equipment used heretofore has included small pressure jets or line clearances so that' theefliciency is lowered.

It is among the objects of this invention to provide in a steam heating system a vacuum return receiver whichis highly efficient, yet simple and inexpensive, which is very efficient in deaerating the condensate therein, which is fully automatic, which utilizes displacement of the condensate for creating a suction on the return lines and utilizes replacement of the condensate for discharging to atmosphere any noncondensable gases that are collected, and which makes use of spraying for escapement ofentrained gases and vacuum and quietude for escapement of dissolved gases by otation from the condensate.

In accordance with this invention condensate in a steam heating system returns to an accumulator through the usual gravity return lines.y Two 'vertical tanks, one of which I call a receiver and the other a discharger tank because it'discharges deaerated condensate to a boiler, receive in succession the condensate from the accumulator. Separate return pipes, connected to the condensate return lines and to the top of the accumulator, draw gases away from the condensate and conduct them to the discharger tank. By such early separation less opportunity is af'- forded for dissolving and entraining corrosive gases. The condensate in one of the tanks is pumped into the other and, upon the operation of control mechanism, this displacement 4,is reversed. The displacement of the condensate from either tank createsV a'vacuum therein that permits the condensate to liberate dissolved gases and causes the entrained gas bubbles to enlarge and separate rapidly from thec'ondensate by flotation. K

The creation of a vvacuum in the receiver tank draws on the accumulator and condensate return lines and thereby assures the distribution of steam to all heating units of the system. Similarly the creation of a vacuum in the discharger tank exerts a pull on the gas return lines of the system. As condensate is pumped from one tank to the other it acts as liquid pistons or plungers in the two tanks. When the liquid piston rises in the receiver tank it forces separated gases out to atmosphere through a check valve, and whenit falls itV draws in condensate and then gases from the accumulator. .Therising liquid piston in thedischarger tank likewise forces separated gases out through a checkvalve, and then forces deaeratedcondensate Yfrom a quiet zone near the bottom of the tank into the boiler feed line. Vapors'inthe tanks arecondensed as condensate is sprayed into them.V

The direction of-thev displacement .fandY replacement of condensate from tank to tank preferably is controlled by valves operated by electric switches responsive to water level and pressure conditions in the receiver tank. When vacuum in the return lines is not desired the operation of the pumping apparatus is controlled by` electric switches responsive to water levels in the accumulator. When vacuum in the return lines is desired the operation of the pumping apparatus is controlled by a vacuum switch responsive to pressure conditions in the accumulator. When continuous operation is desired, all automatic control switches are shunted. If it were not for the desirability of being able to have such automatic intermittent operations, the accumulator could be omitted. Scale and sediment are of little concern because they collect on the bottom of the tanks from which they can be flushed. Likewise no strainers are necessary.

The preferred embodiment of the invention is illustrated in the accompanying drawings in which Fig. 1 is a side view of my apparatus; Fig. 2 is a fragmentary vertical section taken on the line II-II of Fig. l; Fig. 3 is an enlarged section through one of the control valves; Fig. 4 is a vertical section through one of the gas relief valves mounted on the tanks; and Fig. 5 is a wiring diagram for the pumps and automatic controls.

Referring to Fig. l of the drawings, the condensate in a steam heating system returns through pipes I to the bottom of an accumulator tank 2 from the opposite side of which a pipe 3 extends up to the upper portion of a receiver tank 4. A check valve 5 is mounted in pipe 3 to prevent water from being forced from the receiver back to the accumulator. Standing beside the receiver is a discharger tank 6 of substantially the same size. The lower portions of these two tanks are connected by pipes 1 and 8 to the inlets of a pair of pumps 9 and I5 driven by electric motors II and IIa, respectively, and having outlets that are connected by pipes I2 and I3 to a common vertical pipe I4 between the tanks. The upper end of pipe I4 branches out through pipes I5 and I6 t0 the upper ends of the receiver and discharger tanks. Pipes I5 and I6 preferably project into their respective tanks with their inner ends closed but with side walls perforated so as to serve as Spray nozzles, as shown in Fig. 2. A valved makeup water line I1 is connected to the upper end of the receiver, while the lower portion of the discharger is connected by a pipe I8, containing a loaded check valve I9, to a boiler (not shown) It will thus be seen that if the pipes that interconnect tanks 4 and 6 are properly controlled by valves, water in either tank can be pumped into the other. For this purpose piston valves 2l and 22 are mounted in pipes 1 and 8, respectively, while similar valves 23 and 24 are mounted in pipes I5 and I6, respectively. Valves 2I and 24 are connected by tubes 26 and 21 to a magnetic valve 28 that communicates with vertical pipe I4. In the same way valves 22 and 23 are connected by tubes 30 and 3I to a magnetic valve 32 also communicating with pipe I4.

p As shown in Fig. 3, a piston valve 23, which is representative of all the piston valves used in this apparatus, has its movable valve member 23a rigidly connected to the bottom of a piston 23h that is vertically reciprocable in a cylinder 23e above the valve opening. The area of the piston exposed to the fluid pressure in the to-p of the cylinder is materially greater than the bottom of the valve member on which the iiuid pressure in the valve acts. Tube 3I is connected to a cap on cylinder 23e so that the same fluid pressure that acts on the bottom of valve member 23a may also be made to act on the top of piston 23b and, due to the difference in areas, force the valve member down on its seat.

The pressure in the pipe I4 is admitted selectively by magneticvalves 28 and 32 to the tubes connected to the piston valves. When either magnetic valve is opened the other is closed. If magnetic valve 28 is opened the fluid pressure in pipe I4 will act through tubes 26 and 21 on piston Valves 2I and 24 and close those two valves. This will compel the pumps to withdraw condensate from tank 6 through pipe 8 and to deliver it to the top of jtank 4 through pipe I5. When valve 28 is closed and magnetic valve 32 opened, valves 22 and 23 are closed by the fluid pressure in tubes 30 and 3| so that the pumps then withdraw water from tank 4 through pipe 1 and deliver it to the top of tank 6 through pipe I6. Check valves 33 and 34 are mounted, respectively, in pipes I2 and I3 connected to the pump outlets so that either pump can be operated alone if desired.

The magnetic valves 28 and 32 are controlled by a normally open float switch 36 and pressure switch 31 mounted on the receiver and communicating with its interior. A rising water level will close switch 36, and switch 31 also will close when a certain pressure is reached. The closing of both electric switches opens magnetic valve 32 and permits valve 28 to close, while the opening of both switches, upon the falling of the water level in the receiver to a level below switch 36, opens Valve 28 and deenergizes Valve 32.

The pumps may be operated continuously if desired, but when on normal operation lthey are controlled either by a normally closed vacuum switch 38 communicating with the inside of the accumulator, or by normally open oat switches 39 and 40 that are closed when the water level in the accumulator rises sufficiently.

Gases carried over with the steam and returning with the condensate, or gases that leak into the heating system are led away from the condensate lines at various points through pipes 42 which are connected to a pipe 43 that leads to the upper end of the discharger tank. This pipe is provided with a check valve 44 to prevent gases from being forced back through it. The top of the accumulator tank is connected by a pipe 45, containing-a check valve 41, to pipe 43.

The top of each tank 4 and 6 is provided with a gas outlet to which a Vrelief valve 50 is connected. Leading to the atmosphere from this valve is a pipe 5I in which a check valve 52 is mounted so that air cannot be drawn into the adjoining tank through the relief valve. To prevent condensate from escaping from the tank, valve 50 is provided interiorly, as shown in Fig. 4, with a float 53 mounted on the lower end of an arm 54 that is so connected to a vertically reciprocable valve member 55 that it raises the latter to close the outlet of the valve when condensate in the valve lifts the iioat.

A suitable electric circuit by which the electric switches control the magnetic valves and pumps of this apparatus is shown in the wiring diagram of Fig. 5. Electric current from a suitable source is conducted to the motors for the two pumps through wires 60, 6I, and 62 controlled by a magnetic switch 63 in which there is a longitudinally movable spring-biased bar 64 carrying four spaced contact members 65. This switch also includes a solenoid coil 66 which encircles one end of bar 64 and moves it lengthwise when the coil is energized. One end of the coil is connected to wire 60 on the power side of the switch and the other end of the coil is connected by a wire 61 to a hand switch 68. Wire 61 is also connected bya wire 69 to one side of normally open oat switch 4l] near the bottom of the accumulator tank. The other side of this iioat switch is electrically connected to one side of the upper iloat switch 39, and it is also connected by a wire to a Contact 1I in the magnetic switch. The other side of float switch 39 is connected by a wire 12 to a contact 13 opposite contact 1| and also to wire 62 on the power side of the magnetic switch. yA wire 14 connects wire 12 with a contact 15 of the hand switch. AThis contact and the other contact 16 are electrically connected to the vacuum switch 38 on the accumulator tank. Hand switch 68 has a third position, as shown, in which it is open.

With hand switch 68 open the apparatus is set for operation by the float switches 39 and 40 of the accumulator tank. As the condensate level therein rises it first closes switch 40 and then switch 39. As soon as the latter is closed, the solenoid 66 in magnetic switch 63 is energized because a circuit is completed from wire 60 through the solenoid and wires 61 and 69, switches 4I) and 39, and wires 12 and 62. The solenoid draws bar 64 to the left and thereby brings contact members 65 Vinto engagement with wires 60, 6I and 62 and contacts 1| and 13. Electric power is thus. supplied to the pump motors which start operating and continue to operate until the condensate level in the accumulator tank falls below -oat .switch 48 so that both float switches are open. The motor circuit is not broken when switch 39 opens because current continues to flow through wire 1I] and contacts 1| and 13 which were closed by contact member 65.

If it is desired to control the pumps b-y the vac,- uum in the accumulator tank, hand switch 68 is moved to engage contact 16. As the vacuum switch 38 is normally closed the circuit'is completed and solenoid 66 energized so that the magnetic switch 63 is closed.Y When the vacuum in the accumulator tank becomes suflicient to open switch 38 the magnetic switch is opened and the pumps stop operating. The pumps do not start operating again until enough condensate has returned to the accumulator tank either to reduce .the vacuum therein to the point where switch 38 will close or to close float switches 39 and 48 in case the vacuum switch is still open.

Continuous operation of the pumps can be effected by movingl hand switch 68 into engagement vWith contact 15.

To automatically control the direction of flow of the condensate between the receiver and discharger tanks the float Iswitch 36 and pressure switch 31 on the receiver are electrically connected to magnetic valves 28 and 32 through a reverse magnetic switch 89. 'Normally closed `magnetic valve 28 is connected by a wire 8| to Wire 60, and by a wire 82 to a contact 83 in the reverse switch. This contact normally is engaged by one of the contact members 84 mounted on a vertically movable bar 85. The lower contact member 84 also engages contact 86 which is connected by a wire 81 to wire 62. The other magnetic valve 32 is also connected to wire 8|, and by a wire 88 to a contact 8 9 in the reverse switch. The companion contact 90 is connected IIISI to wire 81. To raise bar 85 it is encircled by a solenoid coil 9| connected to contact 9|) and a wire 92 leading to one side of iloat switch 36. The` other side of this switch is connected by a wire 93 to one side of pressure switch 31 and also to a contact 94 in the reverse switch. The other side of switch 31 is connected by a wire 95 to contact 96 that is opposite contact 94 and is connected to Wire 8|.

When magnetic switch 63 is closed so that current is flowing through wires 60 and 62 to the pumps, magnetic valve 28 is closed .as long as receiver tank switches 36 and 31 are open because the lower contact member 84 of reverse switch 80 is resting on contacts 83 and 86. When both switches 36 and 31 are closed the solenoid 9| of the reverse switch is energized, which raises bar 85 to open contacts 83 and 86 and to cause the middle contact member 84 to engage contacts 89 and 96. This opens the circuit of magnetic valve 28 and closes the circuit through valve 32. .The circuit through solenoid 9I is not opened again until both switches 36 and 31 are opened because, even though switch 31 is opened, the circuit is held through contacts 94 and 96 and the upper contact member 84.

The operation of the apparatus disclosed herein will now be reviewed. To control the operation of pumps 9 and I0 by the vacuum in the system., switch 68 in Fig. 5 is moved into engagement with contactv16 in order to place in circuit the vacuum switch 38 on the accumulator accumulator.

tank 2. As the vacuum switch normally is closed, electric power is supplied to the pumps and to magnetic Valve 28 which is thereby opened. The water pressure created by the pumps is exerted through tubes 26 and 21 to close piston valves 2| and 24 in Fig. 1. The pumps must therefore withdraw water from discharger tank 6 through pipe 8 and discharge it through pipes I2, I3, I4, and I5 in a spray into the top of the receiver. As condensate is pumped into the receiver the float switch 36 will be closed and gases are discharged through relief valve 50 on top of the tank. The

. falling condensate level in the discharger tank creates a suction on line 43 and thus withdraws gases from the return lines and the top of the When the condensate rises high enough in the receiver it raises the iloat 53 in the relief valve land thereby closes the valve, whereupon the pressure in the tank builds up until suilicient to close upper switch 31. The closing of switches 36 and 31 energizes reverse switch 80 in Fig. 5 which thereupon breaks the circuitvto magnetic valve 28 and places magnetic valve 32 in circuit. The pump discharge pressure now acts through tubes 30 and 3| to close piston valves 22 and 23 so that condensate is withdrawn from the receiver through pipe I and delivered through pipe I6 into the top of the discharger tank in the form of a spray. The rising `Vcondensate level in the discharger tank forces When the condensate level falls far enough, bothY switches 36 and 31 are open, switch 36 opening after switch 31. Upon opening of switch 36 the reverse switch 80 is deenergized which causes solenoid bar 85 to drop and thereby open the circuit to magnetic valve 32. At the same time the circuit to magnetic valve 28 is closed. Consequently, piston valves 22 and 23 are permitted to open while piston valves 2| and 24 are closed again and the cycle is repeated with the pump now drawing condensate from the discharger to refill the receiver. Whenever suflicient condensate and gases are withdrawn from the accumulator and return lines to. create a vacuum that will open switch 38, the pumps are stopped until enough condensate and gases collect in the return lines and accumulator to reduce the vacuum therein to the point where switch 38 will close.

It will thus be seen that this apparatus is a large two-cylinder` hydraulic pump, the receiver and discharger tanks being the two cylinders and the condensate therein being the liquid pistons or plungers. The plunger action creates a vacuum to withdraw condensate, vapors, and gases from return piping of a heating system, and it condenses the vapors and discharges the non-condensable gases to atmosphere and discharges returned condensate through the boiler feed pipe.

A continuous vacuum is required only during cold lweather when rapid circulation of steam is necessary for adequate heating. During moderate weather power can be saved by opening switch B8 so that the apparatus will be controlled only by float switches 39 and 40 on the accumulator tank. Returning condensate collects in the accumulator until the rising condensate level closes both float switches. This causes magnetic switch 63 to be closed and power to be delivered to the pump in the same way as before. As the receiver withdraws condensate from the accumulator the condensate level therein falls until both float switches are open. This deenergizes the magnetic switch 63 and thereby opens the circuit to the pumps, which do not start operating again until suflicient condensate has returned to the accumulator.

In most cases both pumps need be used only when steam is iirst turned into the steam lines and in very severe winter weather. As soon as the building is fully heated and the normal quantity of condensate is returning, or under normal weather conditions, one pump may be turned 01T. If desired, one pump may be operated continuously and the other automatically by the vacuum switch. The flexibility in the use of power for operating the apparatus gives greater operating efliciency and therefore much less operating costs.

This apparatus is entirely automatic except for the manual selection of the pump control desired. It is simple and inexpensive as compared with other vacuum return receivers and yet is highly efficient and trouble free. In the apparatus described herein the desired vacuum is created by displacement which is one hundred per cent efiicient in creating a vacuum. Therefore, the efficiency of the apparatus for creating a vacuum is the ei'liciency of the electric motors that drive the pumps, and the capacity for vacuum is the capacity of the pumps. Thus, all the work done by the pumps represents condensate returned to the boiler or displaced According to the provisions of the patent statutes, I have explained the principle and construction of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A deaerating vacuum receiver comprising two tanks, the rst having an inlet and the second having an outlet, check valves for said inlet and outlet, a gas relief valve at the top of each tank, a liquid pump, pipes connecting the pump inlet to both tanks, pipes connecting the pump outlet to both tanks, a non-return valve in each pipe provided with iiuid actuated valveclosing means, a pair of normally closed electrically operated valves having their inlets in communication with the pump outlet, piping,l

connecting the outlet of one electric valve to the valve-closing means of the Valve in the pump inlet pipe from one tank and of the valve in the pump outlet pipe to the other tank, piping connecting the outlet of the other electric valve to the valve-closing means of the other two nonreturn valves, and electric control means actu ated by the increase and decrease of liquid in the iirst tank for alternately energizing the two electric valves to open them.

2. A deaerating vacuum receiver comprising two tanks, the rst having an inlet and the second having an outlet, check valves for said inlet and outlet, a gas relief valve at the top of each tank, a liquid pump, pipes connecting the pump inlet to both tanks, pipes connecting the pump outlet to both tanks, a non-return valve in each pipe provided with fluid actuated valve-closing means, a pair of normally closed electrically operated valves having their inlets in communication with the pump outlet, piping connecting the outlet of one electric valve tothe valveclosing means of the valve in the pump inlet pipe from one tank and of the valve in the pump outlet pipe to the other tank, piping connecting the outlet of the other electric valve to the valveclosing means of the other two non-return valves, an electric switch for alternately energizing the two electric valves to open them, and switches responsive to the liquid level and pressure in the first tank electrically connected to said electric switch for operating it.

3. A deaerating vacuum receiver comprising two tanks, the rst having an inlet and the second having an outlet, check valves for said inlet and outlet, a gas relief valve at the top of each tank, a liquid pump, pipes connecting the pump inlet to both tanks, pipes connecting the pump outlet to both tanks, a non-return valve in each pipe provided with fluid actuated valve-closing means, a pair of normally closed electrically operated valves having their inlets in communication with the pump outlet, piping connecting the outlet of one electric valve to the valveclosing means of the valve in the pump inlet pipe from one tank and of the valve in the pump outlet pipe to the other tank, piping connecting the outlet of the other electric valve to the valveclosing means of the other two non-return valves, an electric switch having a set of normally closed contacts and a set of normally open contacts electrically connected to the two electric valves, and electrical means controlled by the increase and decrease of liquid in the rst tank for actuating the switch whereby said electric valves are energized alternately.

4. A deaerating vacuum receiver comprising two tanks, the first having an inlet near its top and the second having an outlet near its bottom, check valves for said inlet and outlet, a gas relief Valve at the top of each tank, a liquid pump, pipes connecting the pump inlet to the lower portions of both tanks, pipes connecting the pump outlet to the upper portions of .both tanks, a non-return valve in each pipe provided with uid actuated valve-closing means, a pair of normally closed electrically operated valves having their inlets in communication with the pump outlet, piping connecting the outlet of one electric valve to the valve-closing means of the valve in the pump inlet pipe from one tank and of the Valve in the pump outlet pipe to the other tank, piping connecting the outlet of the other electric valve to the valve-closing means of the other two nonreturn valves, and electric control means actuated by the increase and decrease of liquid in the first tank for alternately energizing the two electric valves to open them.

5. A deaerating vacuum receiver comprising two tanks, the first having an inlet near its top, a check Valve in said inlet, a gas relief valve at the top of each tank, a, liquid pump, pipes connecting the lower portions of both tanks to the pump inlet, pipes connecting the pump outlet to f the upper portions of both tanks, the second tank having an outlet near its bottom below the pipe connecting the second tank to the pump inlet, a loaded check Valve for said tank outlet, a nonreturn valve in each pipe provided with fluid actuated valve-closing means, a pair of normally closed electrically operated valves having their inlets in communication with the pump outlet, piping connectingl the outlet of one electric valve to the valve-closing means of the valve in the pump inlet pipe from one tank and of the valve in the pump outlet pipe to the other tank, piping connecting the outlet of the other electric valve to the valve-closing means of the other two nonreturn valves, and electric control means acuated by the increase and decrease of liquid in the first tank for alternately energizing the two electric valves to open them.

6. A deaerating vacuum receiver comprising two tanks, the iirst having a condensate inlet near its top and the second having a gas inlet near its top, check valves for said inlets, the second tank having' an outlet near its bottom, a check valve for said outlet, a pump, pipes corinecting .the pump inlet to the lower portions of both tanks, pipes connecting the pump outlet to the upper portions ofboth tanks, a non-return valve in each pipe provided with a piston for closing the valve when fluid pressure is applied to they back of the piston, a pair of normally closed magnetic valves having their inlets in communication with the pump outlet, piping connecting the outlet of one magnetic valve to the back of the pistons in the valve in the pump inlet pipe from one tank and in the valve in the pump outlet pipe -to the other tank, piping connecting the outlet of the other magnetic valve to the back of the pistons in the other two non-return valves, and electric control means actuated by the condensate in the rst tank for alternately energizing the two magnetic valves to open them, whereby condensate is pumped back and forth from one tank to the other and the falling condensate level therein draws condensate and gas in through said inlets.

CHARLES I. BAKER.

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