US2051185A - Steam jet refrigeration apparatus - Google Patents

Description

Aug.. 18, 1936.

E. F.\ STALCUP sSTEAM JET REFRIGERATION APPARATUS v Filed July 2l, 1935 E VHPORRTING CHHHBER A TTU/(NE Y LIQUID to Le CDOLED Patented Aug. 128, 1936 PATENT oFFl'cE 2,051,185 STEAM JET REFRIGERATION APPARATUS Ernest F. Stalcup, Rutledge, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation 'of Pennsylvania Application .luly 21, 1933, Serial No. 681,645l

4 Claims.

My invention relates to refrigeration apparatus of the type known as steam jet refrigeration apparatus, and it has for its object to improve the economy of operation thereof.

A further object is to provide novel and improved means for controlling the amount of refrigerating action of steam jet refrigeration apparatus. v

In refrigeration apparatus of the steam `let type, cooling of liquid is eiected inl a closed chamber by withdrawing vapor therefrom, which is eiected by an ejector motivated by steam or other condensible vapor. The vapor exhausted from the ejector is condensed in a condenser in which it is brought into heat exchange relation with a cooling fluid, usually water. The teml perature of the available cooling iiuid usually varies throughout the year, particularly with the different seasons. The pressure and the temperature of the vapor in the condensing space of the condenser vary with the temperature of the cooling fluid, which means that a lower pressure, or a higher vacuum, may be obtained at certain -times than at other times.

In accordance with my invention, I vary. the admission of motivating uid to the ejector with variation in the absolute pressure in the condensing space of the condenser, the admission being decreased as the pressure decreases;y the ejector being operative with a smaller quantity, or lower pressure, of motivating i'luid as the pressure against which it discharges is reduced. 'I'he admission of the motivating fluid to the ejector is controlled in response to any operating condition which varies with the pressure lin the condensing space, which variable condition may be, for example, said pressure itself, the temperature in the condensing space, or the temperature of the cooling water. The apparatus must be designed for admission of the quantity of motivating uid required for operation with maximum temperature of cooling fluid, and by decreasing said admission as said temperature decreases, I make a substantial saving in the quantity of motivating iiuid admitted, the saving varying with the decrease in temperature of the cooling iiuid.

In accordance with another feature of my invention, I provide valve means between the evaporating chamber and the suction inlet of the ejector, and I control the same to regulate the temperature which the cooling action maint."T at a low valuesuch as the temperature of the water' or other liquid circulated and cooled in the evaporating chamber.

The above and other objects are effected by my invention, as will be apparent from Ithe following description and claims, taken in'connection with the accompanying drawing, forming a part of this application in which:

the vapor inlet 2l of 'a condenser 22.

Fig. 1 is a diagrammatic view of one embodiment of my invention; and,

Fig. 2 is a diagrammatic view of a second embodiment.

Referring now to the drawing more in detail, I show, in Fig. 1, an evaporating chamber III having an inlet II for the admission of liquid to be cooled and an outlet I2 for liquid which hasy been cooled. The latter is connected to a conduit I3, provided with a pump I4, for conveying the cooled liquid to the point of use. The chamber I0 is also provided with a vapor connection I5 connected through a gate valve I6 toy the suction inlet of a steam ejector I'I, the latter com.- prising a nozzle chamber I8 and a converging,- diverging conduit portion I9.

The exhaust end of the ejector is connected to As shown in this case, the condenser 22 is of the two-pass ter box 24, and a reversing chamber 25, and it is also provided with an air outlet 26. .Preferably andas shown, the ejector I'I is connected to the condenser adjacent the warm end of the tubes, and the condensing space 21 is so arranged 'that the vapor ilows over successively cooler portions of the tubes, as indicated by the arrows on the drawing; this arrangement being 'known as a prising a restricted orice plate 29 and a valveY 3l arranged in parallel with each other. The opening provided by the orifice plate is Xed, while the valve 3l is controlled by a bellows 32. The latter is connected by means of a tube 33 to a bulb 34 which is arranged at a suitable'point in the condensing space of the condenser, for example, at the position between the inlet and air outlet shown on the drawing at which any superheat in the exhausted vapor has been removed and at which the iiuid is still primarily condensible vapor as distinguished from the greater portion of air adjacent the air outlet, so that the temperature is a function of the vacuum or absolute pressure against which the ejector exhausts. The bellows 32, the tube 33. and the bulb 34 contain an expansible uid, so that as the temperature in the condensing space increases, the fluid expands and extends the bellows 32. vThe latter opens the valve 3l as it is extended.

y type, having an inlet waterbox 23an outlet wa- 2( steam pressure, that is, with a smaller quantity of steam. As the temperature in the condensing space decreases, the expansible fluid in the l thermostatic bulb 34 contracts, whereupon the closing direction.

bellows 32 contracts and moves the valve 3I in The latter decreases the quantity of steam admitted to the nozzle chamber of the ejector, whereupon the ejector operates with a saving of steam. Due to the greater throttling of the steam, lt' is admitted to the nozzle chamber at a lower pressure. The ejecting function of the ejector, however, is substantially unaffected by the decrease in the quantity of steam for motivating the ejector.

As the temperature of the cooling water increases, the temperaturey and pressure of the vapor in the condensing space also increase. The ejector then requires a greater quantity of steam to maintain it in operation. The increase in temperature c auses the uid in the thermostatic bulb 34 to expand, causing the bellows 32 to expand and move the valve 3| in opening direction, thereby supplying the increased steam required by the ejector. l

In order to regulate the amount of refrigerating action effected by the apparatus, I provide the valve I6 andoperating and .control mechanism therefor. l The valve I6 is of any suitable form, for example, agate valve, and is controlled, in the present embodiment, in response to the temperature of the cooling liquid discharged from the evaporating chamber. For this purpose, I provide a thermostatic bulb 35 disposed in the conduit I3, and containing an expansible uid and connected to a tube 36 to a bellows 31. Due to the relatively large s'ize of the valve I6, a relay operating mechanism is required. I show a uid pressure relay 38 comprising a piston 39 connected to the valve by means of a rod 4I, a pilot valve 42 for controlling the fluid pressure applied to the piston 39, and a' follow-up lever 43 for rethe thermostatic bulb 35, thereby causing the bellows 31 to contract and move the righthand end of the lever 43 upwardly. Fluid pressure is thereupon admitted to the lower side of the piston 39, moving the same upwardly and the valve I6 in closing direction. The upward movement of the rod 4I Atilts the lever 43clockwise about its pivotal connection with the bellows 31 and returns the pilot valve 42 downwardly to cut-01T position. It will be seen that this mechanism provides a given incremental movement of the valve I6 for a given change in temperature,l and operates to provide a valve opening permitting just enough vapor to be withdrawn from the evaporating chamber to maintain the desired temperature of the liquid being cooled.'

Upon increase in temperature of the liquid in the conduit I3, the mechanism operates in the opposite direction to move the valve I6 in opening direction. The increase in the amount of vapor withdrawn from the chamber I effects the increase in refrigeration necessary to maintain the desired temperature of the liquid. It will be apparent that the temperature of the water is maintained within close predetermined limits, a ysmall change in temperature being necessary to effect operation of the valve I6, but for practical purposes the temperature of the cooled water is said to be maintained substantially constant.y 4It is to be understood that the gate valve is controlled to regulate the temperature that is maintained at a low value by the refrigeration apparatus, and that the temperature of the cooled liquid in the conduit I3 ismerely one example of such a temperature.

In Fig. 2, I show my invention embodied in steam jet refrigeration apparatus embodying a plurality of ejectors I1', operating in parallel, such a plurality of ejectors being provided to vary the refrigerator load or capacity. Each ejector is provided with a valve 44 whereby motivating steam Athereto may .be shut oil, and a valve, I6 for cutting oi communication with the evaporatingchamber I0. For this form of'l apparatus, I preferably employ pressure-reducing means for providing steam of predetermined pressure to such ejector or ejectors as are in operation, and I vary the predetermined pressure at which the steam is supplied to the ejector in response to the temperature of the condensing space in the condenser, whereby the quantity of steam supplied to each'ejector is automatically controlled in accordance with changes in pressure in the condensing space independently of the number of ejectors in operation. The steam is supplied from any suitable source to a conduit 45, which is connected to a pressure-reducing valve 46. The latter discharges into a reduced-pressure header 41 with which the ejectors I1 are connected through the respective valves 44. The valve 46 is controlled by a pressure responsive element, such as the diaphragm 48. The pressure in the header 41 is applied to the diaphragm 48-in valve-closing direction through a conduit 49. Av thermostatic bulb 34 is disposed in the condensing space, similarly to the bulb `34, and contains a volatile fluid whose pressure is communicated through a tube 5I to the other side ofthe diaphragm 48 to act in valve opening direction. The valve 46 is biased in opening direction by a spring 52 acting through a hand-wheel 53, which is screw-threaded on the stem and which provides for adjustment of the spring setting.

The operation of the embodiment shown in Fig.l 2 is as follows: for each temperature in the condensing space of the condenser 22', the pressure reducing valve 46 maintains a predetermined pressure in the header 41. The fluid in the thermostatic bulb 34' provides a given pressure on the under side of the diaphragm 48 for a given temperature, so that a given pressure in the header 41, applied to the upper side of the diaphragm 48, is required to balance the pressure on the lowerside. If the pressure in the header is less, the diaphragm 46 moves the valve 46 in opening direction to admit more steam until the given pressure is attained, and if said pressure is more, the diaphragm 48 moves the'valve 46 in closing direction until thepressure in the header 41 is reduced to said given value. For example, if one of the ejectors is shut down, so that less steam is taken out of the header 41, the pressure therein will begin to rise, and the valve-46 will be moved in closing direction, in the manner just described, to maintain the desired given pressure in the header 41.

Upon a decrease in temperature in the condensing space of the condenser, occasioned by decrease in temperature of cooling water providing decreased pressure in the condensing space, the pressure of the' fluid action on the underside of the diaphragm48 decreases, causing the valve 46 to move in closing direction until a lower pressure `is established in the header 41, which lower pressure is acting on the upper side of the diaphragm 48, balances the pressure on the under side. 'I'he decreased pressure in the header 41 results in de,

creased admission to each of the ejectors in operation, since the steam supplied to each ejector varies with the pressure at which the steam is supplied. Upon increase in temperature and pressure'vin the condensing space, occasioned by an increase in temperature of the cooling water,

the pressure in the header 41 is increased so as to supply the increased quantity of steam to each ejector which is required to operate the ejector against the increased pressure in the condensing spa ce.

'I'he relation of pressure in the header 41 to temperature in the condensing space may be adjusted by turning the hand-wheel 53 to adjust Y the spring setting. y Y

' Valve I6 may be operated in any suitable manner, preferably as disclosed in connection with the first embodiment, as shown in Fig. 1.

It will thus be seen that the embodiment shown in Fig. 2, in controlling the pressure at which/,the steam is supplied to each of the ejectors, varies the admission of steam to each ejector in accordance with the variations in temperature and pressure in the condensing space, independently of the number of ejectors in operation.

'From the above description, it will be seen that I have provided apparatus whereby the required quantity of steam or other motivating uid is reduced whenever the temperature of the cooling fluid is below its maximum value2 lIt will also be seen that I have provided means whereby the amount of refrigeration may be readily controlled, and the temperature oi the cooling action maintained substantially constant.

I have used the expression steam jet refrigeration apparatus `for the reason that it is well known in the art and readily conveys the idea of the type`of apparatus to which'the invention relates. As used in the appended claims, the expression includes, not only apparatus using steam, but also apparatus of this type using any other suitable uid, since it is obvious that the invention may be practiced with numerous other fluids.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that, it is not so limited, but is susceptible of various other changes and modications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art liquid therein, condensing means connected to the 10 outlets of said ejectors, means for supplying motivating vapor of predetermined pressure to said ejectors, and means responsive to an operating condition of the condensing means variable with the pressure in the condensing space for varying 15 said predetermined pressure.

2. In vapor jet refrigerating apparatus, the combination of evaporator means adapted to contain liquid, a plurality of ejectors for withdrawing vapor from said evaporator means to effect cool- 20 ing by evaporation of liquid therein, means' for supplying vapor under pressure f'or motivating said ejectors, pressure reducing means between said supply means and the ejectors for maintaining a predetermined pressure of the motivating 25 vapor supplied to the ejectors, means for condensing the vapor exhausted from the ejectors, and means controlling said pressure reducing means to decrease said predetermined pressure in response to variation in an operating condition occurring with decrease in pressure in the condensing space of the condensing means.

3. In vapor jet refrigerating apparatus, the combination of evaporator means adapted to contain liquid, .a plurality of ejectors having their suction inlets connected to Asaid evaporator means for withdrawing vapor from said chamber to effect cooling by evaporation of liquid therein, condensing means connected to the outlets of said ejectors, means for supplying motive vapor of pre- 4* determined pressure to said ejectors, means for selectively controlling the admission of motive vapor to one or more of said ejectors, and means responsive to decrease n a temperature condition of the condensing means for decreasing said pre- 4 vapor Vfrom said evaporator means to effect cool- 5 ing by evaporation of liquid therein, means for supplying motive vapor under pressure for motivating said ejectors, a valve for controlling the admission of motive vapor to one ejector whereby the same may be individually rendered operative 5 or inoperative, a condenser for condensing the vapor exhausted from the ejectors, a pressure reducing valve between said motive vapor supply means and said valve for controlling pressure of the motive vapor admitted to the ejectors, and means for regulating said valve comprising means responsive to variation in an operating condition occurring with decrease in pressure in the condensing space of the condenser for decreasing the pressure maintained by said valve and vice versa and means responsive to the pressure of the motive vapor leaving said valve for controlling, the latter to maintain a substantially constant pressure for each value of said operating condition independently of the number of ejectors in 7 operation.

ERNEST F. STALCUP.

Images