US1969888A - Deaerating steam heating system - Google Patents

Description

5 4- G. H. GIBSON 1, 969, 88 8 DEAERATING s'rmunm'rme syswm 7 Filed July 29, 1932 S'SheBtS-Shet 1 INVENTOR. 6. 50165% 6/550 G. H. e asou 1,969,888

DEAERATING STEAM HEATING SYSTEM ATTORNEY Aug. 14, 1934. G. H. GIBSON 1,969,883

DEAERATING STEAM HEATING SYSTEM Filed July 29, 1932 s Sheets-Sheet s INVENTOR. 'zo/Mi/l 6/550 BY /W W ATTORNEY Patented Aug. 14, 1934 1,969,888 DEAERATING STEAM HEATING SYSTEM George H. Gibson,

upper Montclair, N. 1., as-

signor to Cochrane Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application July 29, 1932, Serial No. 625,784

.7 Claims.

The general object of the present invention is to improve a steam heating system of the so-called vacuum or sub-atmospheric pressure type by providing the same with simple and effective means for separating from the liquid condensate portions of the returns from the radiators, etc., of the system, the air and other gases accompanying and in part dissolved in said condensate. The invention is characterized in particular by the relatively small additions to and changes in a desirable form of existing apparatus of such a heating system required for the separation of air and gases from the condensate. The removal of the air and gases from the condensate preparatory to the return of the latter to the boiler of the heating system possesses important advantages, which will be recognized by those skilled in the art, as comprising the elimination of objectionable corrosion'in the boiler and connected piping, and the elimination of air and gases from admixture with the steam passing from the boiler to the radiators of the heating system.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this.v specification. For a better understanding of the invention, however, its advantages and specific objects obtained with its use, reference should be had to the accompanying drawings and descriptive matter, in which I have illustrated and described preferred embodiments of the present invention.

Of the drawings:

Fig. 1 is an elevation of a portion of a heating system with parts broken away and in section; Fig. 2 is an elevation of a portion of the apparatus shown in Fig. 1, with parts broken away and in section; Fig. 3 is a diagrammatic representation of control features employed with the apparatus of Fig. 1; and Figs. 4 and 5 are partial elevations partly in section and each illustrating a difierent modification of the apparatus shown in Figs. land 2.

In Fig. 1, A represents the return line or conduit of a low pressure steam heating system operating under vacuum or with sub-atmospheric steam pressure. The conduit A is shown as connected at its delivery end to a strainer chamber B including a strainer element B and having an outlet chamber 3*. An outlet connection 0 leads away from the chamber B and forms an extension of the returns pipe. The connection 0 leads to the mixing chamber inlet of an injector D having impeller fluid inlets D discharging through a portion of the mixing chamber into delivery nozzles D and may vwell be provided with a non-return valve C. The nozzles D discharge into a pipe E which leads into the upper end of a chamber E, shown as in the form of a vertical tank. The impeller inlet nozzles D receive impeller liquid from a chamber F' forming or connected to the outlet of a centrifugal pump F, the latter having its inlet F connected to the lower portion of the tank E. The pump F is driven by a motor G, and not only provides impeller liquid to the ejector D but serves also as the boiler feed pump of the heating system, the boiler feed line H being connected to an outlet F from the chamber F. A float E located in the tank or chamber. E rising and falling with the water level therein opens and closes a valve H in the boiler feed line *H, accordingly as the water level in the tank E rises and falls below a predetermined level.

In the prior art apparatus of the type shown in Fig. 1, the tank or chamber E serves simply as a water storage chamber, and the apparatus shown in Fig. 1, insofar as it has now been described, contains nothing novel with me, but, on the contrary, is a typical instance of apparatus employed for receiving and building up the pressure of the returns from a low pressure heating system to separate free and gas from the condensate, but not efieetive to deaerate or eliminatedissolved air and gas from the condensate.

In accordance with the present invention, the chamber E serves both as a water storage chamber and a deaerating chamber, and is provided with a set of water spreading or baflie trays E such as are used in open water heaters and de aerators, above the level of the water in the tank or chamber E, and beneath a spray valve E receiving water from the inlet pipe E. The spray valve, as shown, comprises a valve member E carried by the arm E o1 a rock shaft and yieldingly urged toward its closed position by a loading spring E", the tension of which may be adjusted by a screw and nut E The spray valve E is so arranged, and such operating conditions are maintained that the pressure at which water is supplied to the spray valve is some pounds higher than the vapor pressure in the upper portion of the tank or chamber E, and that the temperature of the water entering the spray is correspondingly higher than the temperature at which water boils when at the vapor pressure within the chamber E. In consequence, when .the stationary switch contacts K the pressure on the water isreleased as it passes out of the spray head, a portion of the water flashes into steam. The fineness of the streams of water discharged through the spray head orifices, coupled with the disruptive effect of the flash action, the retarding and spreading action of the trays E and the fact that the water is at a temperature corresponding to the pressure in the chamber E, results in the efiective liberation from the water as it passes from the spray valve to the pool below the trays, of all air and gases dissolved in the water, as well as any air and gases entrained by the water.

Air and gas are withdrawn from the chamber E, and the desired pressure conditions are maintained therein, by providing the chamber E with an outlet E at its upper end and the connection of said outlet to the condensing chamber of a vent condenser I. The latter, which may be a surface condenser, has. a vent outlet connected by a pipe I to the inlet of a dry air or vacuum pump J driven by the motor G. The vent condenser I is provided with a cooling water inlet and outlet 1 and 1 respectively. The water supplied to the vent condenser inlet 11 may come from any suitable or readily available source, and, after leaving the vent condenser, may supply any suitable demand for such water. For example, the water passing through the vent condenser may well be the supply water for an ordinary hot water service system such as is commonly provided in apartment houses and ofiice buildings. However, the source and utilization of the condensing water is not a matter of importance, because the quantity of water required is comparatively small.

To avoid waste of power in operating the motor G when there is no need for its operation, while insuring the operation of the motor as required to efiect the flow of the returns away from the radiators, etc., of the heating system, I advantageously provide automatic motor control provisions such as those illustrated diagrammatically in Fig. 3 and shown in part in Fig. 1. Those control provisions comprise a vacuum pressure control element ,I-responsive to the excess of atmospheric pressure over the pressure in the returns line, a control element actuated by a float L in response .to the accumulation of water in the returns line, and control means comprising coacting devices P responsive to difference between the temperature of the water passing to the spray valve E and chamber E I As shown ,:the element K comprises a pressure chamber K. in communication with the returns pipe extension C and having one wall formed by a flexible diaphragm K exposed at its outer side to the pressure of the atmosphere. The action of atmospheric pressure on the diaphragm K is balanced in part by the action of a counterweight K adjustably mounted on one arm of the lever K which has the end of its other arm connected to the diaphragm. Also secured to the diaphragm K is a switch actuating element, shown as a switch blade K The switch blade K moves into and out of engagement with accordingly as the excess of atmospheric pressure over the lowerpressure in the connection'C falls below or rises above the amount corresponding to the action of the counterweight K As shown in Fig. 3, the engagement of the contacts K by the switch blade K closes, and their separation opens an energizing circuit including conductors the temperature in the 1, 2, 3 and 4 of an automatic motor starter or controller M, which serves when energized, to connect the motor G to supply conductors 5 and 6 thereof, starting the motor into operation.

As shown, the 'float L outlet chamber B of the strainer B. The stem L of the float L, which rises and falls with the is arranged in thewater level in the chamber or compartment B is connected to and gives corresponding movements to a rod L shown as carrying a bridging switch blade L of engagement with the switch contacts L accordingly as the water level in compartment 1? rises to, or falls below the predetermined height at which the pump B should be operated to pass water from the returns pipe into the chamber E. As shown, the contacts L are connected by the conductors '7 and 8 to the previously mentioned conductors 1 and 2, and complete an energizing circuit for the motor controller when engaged by the switch blade L if the motor controller circuit is not then energized by the engagement of switch blade K with contacts K. In Fig. 3, Q represents a manuallyoperated switch between the contacts K and the conductors 1 and 2, which, when open, leaves the automatic motor starter or controller M subject solely to the control by the float L.

The control means including the devices 0 and P normally operate to complete a control circuit for the motor starter or controller M whenever the excess of the temperature of the water passing, through the spray valve E over the temperature in the chamber E falls below a -.predetermined value. For this purpose. the device O in the arrangement illustrated is shown as a pressure chamber similar to the pressure chamber K, which is connected by a pipe 0 to an expansible fluid thermometer bulb 0' located in the water space of the chamber 1? in the returns line. Similarly, the device P is shown as a pressure chamber like the chambers K and O, and is connected by a pipe P to an expansible fluid thermometer bulb P located in .the water storage space of the chamber E. The diaphragms of the pressure chambers O and P are connected to and operate difierently on a lever OP pivoted at OP between its connections to said diaphragms. Thelever 0P carries a switch actuating element, shown as the switch blade 019 which engages and connects, and. disengages and thereby disconnects b'ranch conductors 9 and 10 connected to the conductors 3 and 4, respectively. accordingly as the switch blade OP is raisedand lowered. The lever OP is tilted to raise and lower the switch blade OP, accordingly as the torque on the leverOP due to the pressure in the chamber P, plus that due to a counterweight OP carried by the lever, falls below or rises above the opposing torque on the lever OP due to the pressure in the chamber 0. The diijference between the pressures in the chambers O and P, and thereby the excess of the returns temperature over the water temperature in the chamber E, is determined by the counterweight CP and may be varied by adjustment of the latter. In the normal operation of the apparatus described, as those skilled in the ,art will understand from theforegoing description, the mixture of .water and gas discharged into the vapor spaceof the chamber-E from the spray valve 13, has its fluidpressure reduced as it enters said .vapor space, so that a portion of the water flashes into vapor. This flash action provides a water vapor content in the vapor space of the cham- The-latter moves into and out ber E eilective to secure the escape from the water spray streams and the water streams flowing down over the agitating and spreading or baflle trays E of the gas previously dissolved in the water. in the water and that carried into the vapor space of the chamber along with, but not dissolved in the water, are withdrawn by the action of the vent condenser, which, in conjunction with the air pump J, maintains a pressure and temperature in the vapor space of thchamber E suitably below the pressure and temperature within the spray valve E to maintain the flashing action. An adequate vapor space volume in the chamber E is maintained bythe action of the float E on the valve H in the boiler feed line, which is opened by the float as required to prevent the flooding of the vapor space.

As those skilled in the art will understand, it is ordinarily necessary to feed water to the boiler of the heater system only as water is returned 'from the radiators and pipingf'of the heating system to thechamber E, since in such a system any significant leakage occurring in ordinary operation is not outleakage of water, but inleakage of air, so that make-up water needs to be added to the system only at such infrequent intervals that its addition need not affect the normal operation of the system. Ordinarily, the supply of make-up water is automatically supplied as its need is indicated by an undue decrease in height of boiler water level. and the make-up water supplied may advantageously be added to the returns passing to the deaerating chamber E.

While in the form of the invention illustrated in Figs. 1 to 3, the ejector D serves, as previously described, to build up the pressure of the returns and thereby augment the spray or jet velocity of the-water discharge through spray valve E into the chamber E, the use of the ejector is not essential to the use of the invention in its broader aspects. For example, by locating the receiver chamber B above the level of the chamber E and connecting the receiver supply pipe E directly to the lower portion of the chamber 3*, as shown in Fig. 4, the water and air constituents of the returns can pass directly from the chamber B to the chamber E when not prevented by the closure of the spray valve E. which the motor G is temporarily out of operation, water may accumulate in the chamber B of Fig. 4 and seal the inlet end of the pipe connection E, so that temporarily air cannot pass out of the chamber B; but' when thereafter 'the motor G is started into operation, it

quickly lowers the water level in the chamber B,

so that air as well as water may then pass from the latter to the chamber E. In Fig. 4, the vent condenser-I is shown as connected by pipe E to the chamber E at alevel between the bottom of the trays E and the water level in-the chamber E. This 'is not a necessary incident of the manner in which the returns arepassed to the chamber E in Fig. 4, but is merely illustrative of the fact that the difference between the vent locations of Figs. 1 and 4 is not of controlling importance; I note, however, that the vent location of Fig. 4 is ordinarily somewhat preferable to that shown in Fig. 1, in flash deaerating apparatus of the kind disclosed since such vent location insures that the flashed vapors will sweep downward through the trays, and also takes advantage of the fact that air is heavier than water vapor.

While with the arrangements shown in Figs.

The gas thus forced out of solution water in the piping E without liability of the dis- At periods in- 1-4, all of the returns are passed from the returns conduit into the receiver E, in some cases, I may advantageously pass into the deaerating receiver E onlythe water constituent of the returns. For example, as shown in Fig. 5, the entire returns withdrawn from the returns conduit by the ejector D may have its pressure increased by the ejector to a pressure sufliciently above that of the atmosphere to permit of the separation of the liquid and free gaseous constituents of the returns in the discharge piping of the ejector, with the discharge to the atmosphere of the free gaseous constituent through-a standpipe extension E" from the piping E through which the liquid constituent only of the returns is passed to the spray valve E. Such separation of the liquid and gaseous constituents of the returns, and the diversion of the latter constituent from the receiver E, reduces the de- With the arrangement shown in Fig. 5, the standpipe E should be extended upwardly sufliciently. to permit some fluctuating in the pressure of the charge or spillage of water by overflowthrough the standpipe.

With the arrangements shown in Fig. 5, as with those shown in the other figures, the maintenance of the flashing action requires the maintenance in the deaerating chamber of a temperature sufliciently below the temperature of the water sprayed into the chamber. For an adequate flashing action it is in general necessary that the temperature at which the water comes to the spray head should be some 20 to 25 in excess of the temperature maintained within the vapor-space oi' the chamber E. In consequence when the pressure of the water is increased by the action of the ejector without a corresponding increase in the temperature at which the water passes to the spray head, there can be no corresponding. increase in the vapor pressure maintained within the chamber E.

In addition to the primaryadvantages of effective air removal from the water passing to m the boiler given by the' invention, the latter is characterized by the fact that effective deaerareturns and for supplying feed water to the boiler of the heating system. The air pump required is relatively small and inexpensive, both from the standpoint oi installation cost and cost oi operation.

While in accordance with the provisions of the statutes, I have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent'to those skilled in the art that changes may be made in the forms of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that in some cases certain features 01' my invention may be used to advantage without a corresponding use or other features. 7

Having now described my invention, claim as new and desire to secure by Patent is:

1. In apparatus for handling the returns from a low pressure heating system, the combination what I Letters with the system returns conduit, of a receiver enclosing a vapor space, means receiving returns from said conduit and spraying said returns into said vapor space, meansfor withdrawing gas from said space and maintaining a pressure therein lower than the fluid pressure in theflrst mentioned means so that a portion of the water constituent of the returns may flash into vapor when sprayed into said receiver, said last mentioned means comprising a vent condenser connected to said vapor space and vapor exhausting means connected to said condenser, and controlling means for said exhausting means reponsive both to the pressure and to the accumulation of water in said conduit.

2. In apparatus for handling the returns from a low pressure heating system, the combination with the system returns conduit, of a receiver enclosing a vapor space, means receiving returns from said conduit and spraying said returns into said vapor space, means for withdrawing gas from said space and maintaining a pressure therein lower than the fluid pressure in the first mentioned means so that a portion of the water constituent of the returns may flash into vapor when sprayed into said receiver, said last mentioned means comprising a vent condenser connected to said vapor space and vapor exhausting said chamber, water ing said valve to regulate said means connected to said condenser, and controlling means for said exhausting means responsive both to the pressure and to the accumulation of water in said conduit and responsive to the diflerence between the returnstemperature and the receiver temperature.

3. In apparatus for handling the returns from a low pressure heating system, the combination with the system returns conduit, of a receiver, means receiving returns from said conduit, increasing the fluid pressureftliereoi and spraying said returns into the upper portion of saidreceiver, means regulating the discharge of water from the receiver to maintain the vapor space in the upper portion of the latter, and means including mechanism responsive to the difference between the temperatures in said conduit and in said receiver for maintaining a pressure in said vapor space lower than said fluid pressure so that a portion of the returns water may flash into vapor when sprayed into said receiver.

4. In apparatus for handling the returns from a low pressure heating system, the combination 'with the system returns conduit, of a receiver chamber,

an ejector having an inlet chamber connected to said conduit, a discharge nozzle and an impelling liquid inlet, a pump drawing water from the lower portion of said chaniber and having an outlet supplying water under increased pressure to the inlet of said ejector, and having a second delivery outlet, a valve controlling the last mentioned outlet, means responsive to the height of water level in said chamber for adjustlevel and thereby maintain a vapor space in the upper portion of spray means receiving water discharged from said discharge nozzle and spraying it into said vapor. space and means for maintaining a pressure in said space lower than the pressure in said conduit comprising a vent condenser connected to said space and an air pump connected to said vent condenser.

of the returns, discharging 5. In apparatus a low-pressure heating system,.the combination with the system returns conduit, of a receiver, means receiving the returns from said conduit, increasing the fluid pressure thereof and spraying the water constituent of said returns into the upper portion of said receiver, means regulating the discharge of water from the receiver to maintain a for handling the'returns from vapor space in the upper portion of the latter,

means for'maintaining a pressure in said vapor space lower than the first mentioned pressure so that a portion of the water constituent of the returns may flash into vapor when sprayed into said receiver, said last mentioned means comprising a vent condenser connected to said vapor space andvapor exhausting means connected to said a common motor for operating said exhausting means and the first mentioned means and controlling means for said motor responsive both to the pressure and to the accumulation of water in said condui 6. In apparatus for handling the returns from a low pressure heating system, the combination with the system returns conduit, of a receiver, means receiving returns from said conduit, increasing the fluid pressure thereof and spraying the water constituent of said returns into the upper portion of said receiver, means regulating the discharge of water from the receiver to maintain a vapor space in the upper portion. of the latter, means for maintaining a pressure and temperature in said vapor space lower than the flrst mentioned pressure and the returns temperature, respectively, to cause a portion of the water constituent of the returns to flash, into vapor when sprayed into said receiver, said last mentioned means comprising a vent condenser connected to said vapor space and vapor exhausting means connected to said condenser, a common motor for operating said exhausting means and the first mentioned means, and means responsive both to the accumulation of water and to the pressure in said conduit for operating said motor as required to prevent said accumulation and pressure from exceeding predetermined maximum values thereof.

'L'In apparatus for handling the returns from a low pressure heating system, the combination with the systems returns conduit, of a receiver enclosing a vapor space, means receiving the returns from said conduit increasing the pressure the gaseous constituent thereof into the atmosphere, and spraying the liquid constituent thereof into said vapor space, means for withdrawing gas from said vapor space, and means including mechanism responsive to the difference between the temperatures in said conduit and in said receiver for regulating the relative rates at which liquid is sprayed into and gas is withdrawn from said vapor space to maintain a temperature and pressure in the vapor space respectively lower than the temperature of said liquid constituent and the pressurev at which the latter will boil when at the last mentioned temperature, whereby a portion of said liquid constituent flashes into vapor when sprayed into said receiver.

GEORGE H. GIBSON.

Images