US3082750A - Boiler feed system - Google Patents

Description

March 26, 1963 D. M. MISNER 3,082,750

BOILER FEED SYSTEM Filed Nov. 18, 1960 2 Sheets-Sheet 2 ash as 87 Q I S ;,as Q ey ll U Q -aa 7 7 'd 7 I an I /0 l 0 by @2144. a M

uiltioflney United States Patent 82,750 BOILER FEED fiYSTEM David M. Misner, situate, Mass, assignor to C. R. Swaney Co., inc, Waltham, Mass, a corporation of Massachusetts Filed Nov. 18, 1am, der. No. 70,206 2 Claims. (Ci. 122-4-5l) This invention relates to a boiler feed system. Such systems usually include a pump for pumping water into the boiler and control means responsive to variations in the water level in the boiler and operative when said water level falls below a predetermined low point, to set the pump in operation, and to deactivate the pump when said water level has risen to its normal point.

One object of this invention is to provide a boiler feed system of the above type in which, while the operation of the pump is controlled by the variations in the Water level in the boiler yet the actual delivery of said water into the boiler is controlled by the pressure of the water delivered from the pump after it has been started.

One way in which this may be accomplishedis to provide a normally closed supply valve in the pipe connecting the pump to the boiler and also to provide means rendered operative by the pressure of the water delivered by the pump to open said supply valve.

In the drawings wherein one embodiment of my invention is illustrated:

FIG. 1 is a somewhat diagrammatical view of a boiler feed system embodying the invention;

FIG. 2 is an enlarged sectional view in perspective showing a flow retarding device which is used in the system;

FIG. 3 is a sectional view of the supply valve; and

FIG. 4 is a more or less diagrammatic view of the control means which responds to variations in the water level in the boiler and operates to start the pump when the water level in the boiler reaches a predetermined low position.

Referring ot FIG. 1, 3 indicates a boiler, which may be used for supplying steam to a heating system, the water level in the boiler being maintained by the device embodying the invention and which will be presently described. 4 indicates a receiver which is piped to receive the returns from the heating system, the delivery end of such pipe being indicated at 5. Said receiver is herein shown as being vented to the atmosphere by means of an open vent pipe 6, with the result that atmospheric pressure is maintained within the receiver, but the apparatus could be operated if the pressure in the receiver was higher or lower than atmospheric pressure. The water from the receiver is delivered into the boiler as occasion arises, by means of pump P which is driven by a motor M. The operation of the motor is automatically controlled by a control device responsive to variations in the water level in the boiler and for this purpose the motor circuit 7 is provided with a control switch, illustrated diagrammatically at 8, which is open so long as "the water evel in the boiler is above a prescribed minimum point but which is automatically closed when the water level in the boiler drops below said prescribed minimum level.

The receiver 4 is connected to the intake of the pump P by a pipe connection 9 and the discharge opening of said pump is connected to the boiler by a pipe connection it? which has a normally closed supply valve 11 therein and also a check valve 12.

The control means for automatically closing the motor circuit when the water level in the boiler drops to a prescribed low point includes a float chamber 13 which is connected to the boiler by pipe connections 14 so that the water level in said chamber is always the same as that in the boiler. This float chamber 13 has a float 15 therein carried by a stem 16 which is pivotally mounted at 17, and said stern has rigid therewith an arm 34 which is connected by a connection 18 with the switch 8 so that as the water level in the boiler drops the connection 18 moves upwardly, and when the water level in the boiler reaches the prescribed low point the connection 18 will have been moved upwardly into a position to trip the switch 8 in the motor circuit 7 to its closed position thereby setting the pump P in operation.

Means are provided whereby whenever the water in the boiler 3 reaches said prescrirbed low level and the motor M is thereby activated to set the pump P in operation, the water which is delivered from the pump under pressure becomes operative to open the supply valve 11 thereby allowing the pump to deliver water directly into the boiler. When the water level in the boiler has risen to its normal point the switch 8 will be opened by the rising movement of the float 15, the pump P will cease to operate and the supply valve 11 will be automatically closed again and will remain closed until the water level in the boiler again drops to the low point.

The supply valve is herein shown as in the form of a diaphragm valve and it embodies a valve body 20 containing a valve member 21 by which the port 21a is closed or opened. Said valve is provided with an elongated stem 22 that extends upwardly through a tubular housing 23 that is attached to the valve body and has at its upper end an enlarged portion 40 that provides a diaphragm-receiving chamber 24 into which the valve stem 22 projects. Said diaphragm-receiving chamber encloses a flexible diaphragm 25 and the valve stem 22 carries at its upper end a head 26 situated directly beneath said diaphragm. Enclosed in the housing 23 is a spring 27 which is supported by a stationary collar 29 that is fixedly secured to said housing 23. The upper end of the spring 27 engages the head 26 and the construction is such that said spring maintains continuously an upward pressure against the head 26 thereby normally holding the valve 2-1 yieldingly in closed position as shown in FIG. 3.

Means are provided whereby when the condition within the boiler calls for additional water and the motor M and pump P are activated, the pressure of the water delivered by the pump will function to depress the diaphragm 25 and the head 26 and thereby force the valve stem 22 and valve member 21 downwardly thereby overcoming the valve-closing action of the spring 27 and unseating the said valve member 21 and thus opening the supply valve 11.

For this purpose an auxiliary pipe 28 is connected to the pipe 10 on the supply side of the supply valve 11, said pipe 28 leading into the diaphragm chamber 24 above the diaphragm 25. With this construction the water which is delivered from the pump when it is started will be delivered into the pipe 28 and into the diaphragm chamber 24 above the diaphragm 25 and will apply a downward pressure on said diaphragm 25 which will press it against the head 2x5 with suflicient force to move the valve stem 22 downwardly and unseat the valve member 21 and thus open the supply valve 11.

The auxiliary pipe 28 also contains a second valve 30 which is operatively connected to and actuated by the float 15, the construction being such that when said float drops to the low position at which the switch 8 is closed it will also open the valve 39 thereby providing an unobstructed passage from the pipe it to the portion of the diaphragm chamber 24 above the diaphragm. The valve 30, as herein shown, comprises a casing 32 enclosing a valve member 31 which is connected by a connecting element 18 with the float actuated arm 34-, which arm as stated above, controls the opening and closing of the switch 8.

The pipe 28 is made in two sections, a first section 28a that connects the pipe 16 with the casing 32, and a second section 28b that connects the casing 32 with the diaphragm chamber 24. The casing is provided with an annular valve seat 30b on which the valve member 31 seats to close the valve and the opening through said valve seat which communicates with the pipe section 28b.

The operation of the above described boiler feed mechanism is as follows:

So long as thewatcr level in the boiler is within the normal operative range and the float 15 is in its normal operative position, the switch 8 will be open as shown in FIG. 1, and both the supply valve 11 and the valve 30 will be closed. If, however, the water level in the boiler drops elow the prescribed low level point the resultant downward movement of the float 15 will close the switch 3 and also completely open the valve 36. The closing of the switch 8 will activate the motor M and set the pump P in operation, but because the supply valve 11 is closed no water can be pumped into the boiler 3 when the pump is first started. However, delivery from the pump of water under pressure will fill the pipe 1% between the pump and the supply valve 11 and also fill the pipe 28 and the portion of the diaphragm chamber 24 above the diaphragm 25. The pressure thus applied to the diaphragm forces the head 25 downwardly thereby opening the supply valve 11 as above described, thereby providing free flow of the pumped water into the boiler.

As the water is thus added to the boiler the water level therein will rise and when said water level has risen to its normal operative level the resulting upward movement of the float l and downward movement of the connection 13 will have moved the latter into a position to trip the switch 8 to its open position, thus deactivating the motor M and stopping the pump P. Such upward movement of the float 15 will also move the valve member 31 toward its closed position. The connection between the valve member 31 and the float 15 however is such that when the float rises to the point at which it trips the switch 8 to open position the valve 30 will not be completely closed.

Provision is made, however, whereby as soon as the switch 8 is opened and the motor M ceases to operate the pump, the pressure in the pipe section 2811 and on the diaphragm 25 will be gradually reduced sufliciently to allow the spring 27 to return the valve member 21 to its closed position, thus closing the supply valve 11. This is accomplished by connecting the pipe section 23b with a return pipe 33 leading to the receiver 4, and providing said return pipe with a restricted orifice which allows a slow leakage of the water from the diaphragm-receiving chamber 24 and said pipe section 2811 into the return pipe 33 thereby reducing the pressure on the diaphragm. As such leakage takes place the compressed spring 27 automatically raises the head 26 and thus closes the valve member 21 onto its seat as described above. If the valve 30 has not been completely closed said leakage through the restricted orifice will relieve the pressure not only in the pipe section 2811 and in the diaphragm chamber 24 but also in the pipe section 28a and in the pipe 10.

The restricted orifice may be provided in various ways. As shown in FIG. 2, the return pipe 33 has a coupling member 35 therein which has a partition 36 that closes said pipe except for the small orifice 41. The size of the orifice is so small that when the pump P is operating the pressure developed thereby is not appreciably affected by the leakage through said orifice, but when said pump stops and the valve 30 is closed the pressure in the diaphragm chamber 24 is reduced to the point which will allow the spring 27 to close the supply valve 11.

While the above description refers to a boiler feed system having a single boiler yet the invention is adapted for use in boiler feed systems which include two or more boilers that are under the control of a single pump and its motor. In the drawings a second boiler 3a is shown which duplicates in all respects the boiler 3 and its acccssories such as the float chamber 13, the float 15, and the switch 8, and the means by which it is actuated by the float, the supply valve 11, the valve 3%, the pipe connection 28, the flow retarding orifice 41 etc. These accessories for the boiler 3a are identified by the same reference numerals as those used for the corresponding accessories for the boiler 3, except that each reference numeral for the accessories for boiler 3a carries the exponent a. The water for the boiler 3a is supplied through a pipe 13a which is connected to the pipe 1%), and the boiler 32: has a return pipe 33a by which the water passing through the restriction coupling 35a is returned to the receiver 4-. The switch 8a is in a branch circuit 7a which is connected to the power circuit 2 in parallel with the circuit '7 for the switch 8.

A single pump P and motor M will thus serve both boilers and the feed system in each boiler will function independently. If the water level in boiler 3 falls below the prescribed minimum point, the switch 8 will be closed thereby setting the pump P in operation and causingwater to be delivered into said boiler as above described. This will have no effect on boiler 5a so long at its water level is normal because under normal conditions both the valve and the supply valve 11a for the boiler 3a are closed and no water delivered by the pump P can reach the diaphragm chamber of said supply valve 1.10. However, if while the pump P is delivering water to boiler 3, the water level in boiler 3:: falls below the critical point and the float 15:: moves downwardly suflicicntly to close the switch 3a and to open the valve 30a, then water delivered by the pump P will also be delivered into the diaphragm chamber of supply valve 11a thereby opening said valve to permit said water to be fed into the boiler 3a.

So long as either of the switches 8 or 8a is closed the pump P will be operating and water will be fed to the corresponding boiler, while if at any time both switches are closed then the pump will feed water to both boilers. When the water level in one of the boilers (boiler 3 for instance) reaches its normal level, the switch 8 will be opened as above described, and the valve 30 will be nearly but not quite closed. If at the time of opening of switch 8 the water level in boiler 3a is still below its normal operative level, the switch 8a will still be closed and the pump P will still be operating. Said pump will then be pumping water into boiler 3a and also into boiler 3 because the pressure of the pumped Water in the pipe 28 will maintain sufficient pressure on the diaphragm 25 through the partially opened valve 3b to hold the supply valve 11 open. The water level in boiler 3 will therefore continue to rise and when it has risen A" or so above the switch-tripping level for switch 8 the valve 30 will have been completely closed thereby shutting ofl the water in the pipe section 28b from the continued pressure of the water delivered by the pump P. The leakage through the restricted orifice 41 of the water in pipe section 28b will relieve the pressure on the diaphragm 25 sufiiciently to allow the spring 27 to close the upply valve 11 and thereby stop the delivery of water to the boiler 3.

If the system is expanded to include three or more sep arate boilers, all of which are served by a single pump and its motor, each boiler will still be capable of receiving water from the pump independently from any other boiler as above described.

Means are provided for adding make-up water to the receiver 4 in case the amount of water which is delivered to said receiver through the return pipes is not sufficient to maintain the proper level in said receiver. Such means may have any usual construction and as illustrated diagrammatically in FIG. 1 of the drawings there is a supply pipe 42 leading from a supply of make-up water and a float operated valve 44 (shown diagrammatically in the drawings) which is closed so long as the water level in the receiver is above a predetermined maximum point but is opened when the Water level in said receiver drops below a predetermined minimum point. Hence when the Water level in the receiver drops to a minimum point the valve 44 will be automatically opened and added make-up water will be supplied to the receiver through the pipe 42, said valve being closed when the maximum water level in the receiver has been established.

Inasmuch as this type of valve is well known and is in common use it is not thought to be necessary to illustrate said valve in detail.

The receiver 4 is provided with an overflow pipe 43 through which water may be discharged if the water level in said receiver rises above the maximum level.

One of the important features of the invention is that if it is used in a boiler feed system which contains a plurality of boilers, all of which are supplied with make-up water by the same pump, the system will function properly even though the pump runs continuously.

So long as the Water level in any boiler is at its normal point, the supply valve 11 for the corresponding boiler will be closed so that even if the pump is operating no water can be supplied to said boiler. Each supply valve 11 is opened when the corresponding valve 30 is opened to admit pumped water into the diaphragm chamber of said supply valve, and the opening of each valve 30 is controlled by the water level conditions in the corresponding boiler, said valve being opened when the water level falls to a minimum point and being closed so long as the water level in said boiler is at its normal point. Hence even if the pump which supplies Water to all of the boilers is running continuously, the supply valve 11 for any boiler will only be opened when the corresponding valve 30 for said boiler has been opened because the water in said boiler has fallen to its low minimum point. Although the switch 8 is shown diagrammatically in FIGS. 1 and 4 it will be understood that switches or" this type are commonly so made that as the float 15 moves downwardly and the connection 18 or its equivalent moves upwardly due to a falling water level in the boiler said connection will at the proper point trip the switch to a closed position and when the water level in the boiler is rising as water is being pumped into the boiler, the consequent downward movement of the connection 18 will at the proper point trip said switch to an open position. Since switches of this type are well known and in common use it is not regarded as necessary to illustrate such a switch in detail.

I claim: 7

1. In a boiler feed system which includes provision for a plurality of boilers, the combination comprising asource of water supply, pipe connections adapted to extend between said source of water supply and each of said boilers, a single pump for pumping water through each of said pipe connections into the respective boilers, liquid level actuated electric switch and pilot valve means for each of said boilers and adapted to be activated in response to a predetermined minimum liquid level of the associated boiler, pressure operated normally closed supply valves in each of said pipe connections, an electric circuit connecting said electric switch means for energizing said pump whenever the water level in any of said boilers is below said predetermined minimum liquid level, and a pipe connection extending from the outlet of said pump through each of said pilot valves, means to supply operating pump pressure to open the respective supply valve when the associated pilot valve means are actuated in response to said predetermined minimum level adapted to supply water to each of said boilers having a water level below said minimum liquid level, said supply valves having a pressure chamber for receiving pump pressure via said pilot valve means and a bleed line connected to said chamber, said bleed line including means providing a reduced size orifice effective to bleed operating pressure from said chamber and close said supply valve only after pressure :from said pump to said chamber has been interrupted by the said pilot valve means.

2. Apparatus according to claim 1 in which said liquid level actuated electric switch and pilot valve means is adapted to operate in response to a rise of the water level in the associated boiler to first open said electric switch means and in response to a further rise of the water level in said boiler to then close said pilot valve means.

References Cited in the file of this patent UNITED STATES PATENTS 1,966,898 Mastenbrook July 17, 1934 2,288,223 Bomyer June 30, 1942 2,322,102 Gschwind June 15, 1943 2,324,695 Hamilton et a1 July 20, 1943 2,707,459 Swaney May 3, 1955

Claims (1)

1. IN A BOILER FEED SYSTEM WHICH INCLUDES PROVISION FOR A PLURALITY OF BOILERS, THE COMBINATION COMPRISING A SOURCE OF WATER SUPPLY, PIPE CONNECTIONS ADAPTED TO EXTEND BETWEEN SAID SOURCE OF WATER SUPPLY AND EACH OF SAID BOILERS, A SINGLE PUMP FOR PUMPING WATER THROUGH EACH OF SAID PIPE CONNECTIONS INTO THE RESPECTIVE BOILERS, LIQUID LEVEL ACTUATED ELECTRIC SWITCH AND PILOT VALVE MEANS FOR EACH OF SAID BOILERS AND ADAPTED TO BE ACTIVATED IN RESPONSE TO A PREDETERMINED MINIMUM LIQUID LEVEL OF THE ASSOCIATED BOILER, PRESSURE OPERATED NORMALLY CLOSED SUPPLY VALVES IN EACH OF SAID PIPE CONNECTIONS, AN ELECTRIC CIRCUIT CONNECTING SAID ELECTRIC SWITCH MEANS FOR ENERGIZING SAID PUMP WHENEVER THE WATER LEVEL IN ANY OF SAID BOILERS IS BELOW SAID PREDETERMINED MINIMUM LIQUID LEVEL, AND A PIPE CONNECTION EXTENDING FROM THE OUTLET OF SAID PUMP THROUGH EACH OF SAID PILOT VALVES, MEANS TO SUPPLY OPERATING PUMP PRESSURE TO OPEN THE RESPECTIVE SUPPLY VALVES WHEN THE ASSOCIATED PILOT VALVE MEANS ARE ACTUATED IN RESPONSE TO SAID PREDETERMINED MINIMUM LEVEL ADAPTED TO SUPPLY WATER TO EACH OF SAID BOILERS HAVING A WATER LEVEL BELOW SAID MINIMUM LIQUID LEVEL, SAID SUPPLY VALVES HAVING A PRESSURE CHAMBER FOR RECEIVING PUMP PRESSURE VIA SAID PILOT VALVE MEANS AND A BLEED LINE CONNECTED TO SAID CHAMBER, SAID BLEED LINE INCLUDING MEANS PROVIDING A REDUCED SIZE ORIFICE EFFECTIVE TO BLEED OPERATING PRESSURE FROM SAID CHAMBER AND CLOSE SAID SUPPLY VALVE ONLY AFTER PRESSURE FROM SAID PUMP TO SAID CHAMBER HAS BEEN INTERRUPTED BY THE SAID PILOT VALVE MEANS.

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