US2029106A - Refrigerating system - Google Patents

Description

Jan. 28, J KlRGAN REFRIGERATING SYSTEM Filed Dec. 19, 1934 IN VEN TOR.

Joli/n BY W 2k HIS A TTORNEY Patented Jan. 28, 1936 nnrmoaaarmc SYSTEM .lolm Kirgan, East'on, Pa, assignor to Ingersoll- Rand Company, Jersey City, N. J., a corporation of New Jersey Application December 19, 1934, Serial No. 758,183

Claims.

This invention relates to improvements in refrigerating apparatus, and particularly to means for controlling same and avoiding waste of power in the operation thereof.

In refrigerating systems of the water-vapor type a liquid refrigerant, such as water, is cooled by vaporizing a part thereof. The vaporization is carried out in a vessel called an evaporator and the vapor is extracted by an evacuator, which simultaneously compresses the vapor and transfers it to a condenser to liquefy it. If the evacuator is a steam jet ejector, both the vapor from the evaporator and the steam used in the operation of the jet are liquefied in the condenser.

When the pressure in the condenser is high with respect to that in the evaporator, more steam at higher pressure is needed to remove a given amount of water-vapor from the evaporator; and less steam at lower pressure is required when the difierence in the pressures of the condenser and the evaporator is reduced.

An object of the invention is to provide means whereby the consumption of steam is regulated in accordance with pressure conditions in the evaporator and condenser, the pressure in the one being opposed to the pressure in the other and the quantity of steam expended being nicely controlled by the resultant efiect thereof, so that waste of power is avoided.

Another object of the invention is to facilitate starting of the apparatus without interference from any of the controlling devices in the system.

An additional object of the invention is to provide a member between the condenser and the evaporator subjected to pressure conditions in both so that an element therein'will be actuated to regulate the steam for the ejector as working conditions demand; and to enable the connection of the evaporator with said member to be interrupted when the evacuator is not working. This arrangement is particularly useful when a multichamber evaporator is employed to enable the system to operate through a. wide range of load from full load to part load.

A further object of the invention is to provide means whereby the maintenance of conditions as above outlined for the correct operation of the invention is always assured.

These and other objects and advantages of the invention are set forth in the following description and the novel features are pointed outin the appended claims. The disclosure, however, is illustrative only and many changes maybe made in practice without departing from the principle (iUl. 62-152) of the invention or exceeding the scope and spirit thereof. v

On the drawing, Figure 1 shows an outline of one form of the invention, and

Figure 2 is a top view indicating how the invention can be employed when the evaporator contains several chambers; and

Figure 3 is a section of a detail.

On the drawing the numeral i indicates an evaporator to which a liquid refrigerant, such as water, is supplied by way of a pipe 2. In the evaporator this pipe is connected to a spray device 3 which delivers the water in the form of several jets. Some of the water is vaporized at once, while the remainder settles on the floor of the evaporator and is withdrawn through a conduit 4 which carries the chilled water to a place where the refrigerating eiiect is desired. Here the water absorbs heat and can be returned by way of the conduit 2 and be used again.

At the top of the evaporator is an evacuator in the form of a steam-jet ejector or thermo-compressor 5 connected to a condenser 6 by way of a discharge casing 7 of the usual design. The ejector 5 is supplied with steam through a pipe 8 and in operation, the steam creates a sufliciently high vacuum in the evaporator I to start the evaporation and transfer the vapor from the evaporator to the condenser 6. During operation the necessary vacuum is maintained by the ejector 5.

In practice several pounds of steam must be used for every pound of water vapor that is extracted from the evaporator l. The quantity of steam needed varies according to either the refrigerating load or the temperature of the water supplied to the condenser to cool the latter. In either case theconditions inside the condenser undergo a change and theoperation of the steamjet ejector is afiected thereby. When the pressure and temperature within the condenser increase, more steam is necessary, and if these factors rise too high, the operation of the steam-jet ejector may even be stopped. When used for this purpose, the steam-jet ejector has a substantially constant capacity and the quantity of water va- 5 per which it willremove from the evaporator at the low vaporization pressures usually employed and deliver to the condenser is approximately the same, regardless of the amount of steam used, so long as the pressure in the evaporator remains unchanged. Also a steam-jet ejector can not be regulated ordinarily by hand, but must be turned on full at whatever pressure the'steam is supplied.

To regulate such an ejector therefore requires means which will permit the ejector to discharge just the right quantity of steam and no more, to produce the maximum vapor-removal eflect rfor the pressure and temperature prevailing in the evaporator atga iven moment.

The pressure in the condenser, of course, epposes the admission of steam and. vapor, and if this pressure exceeds a predetermined amount, and the ejector ceases to operate no more water will be cooled for the time until the evaporation pressure has greatly increased and the temperature of the chilled water has risen to a considerable extent. To obtain regulation in the manner required by the above conditions, theiibottom'of the condenser and the top of :the evaporator are connected by a U-shaped trap member 9 which contains a float element I10. This element it is mounted uponan arm H fixed to a pivot 52 that extends outside of the member 9. On its exterior end the pivot 82 bears a rigid arm 03 joined by a link 44 to an arm id ot a rotary valve to in the steam pipe 8." The trap member will fill with the condensate in the condenser and as the pressure in the condenser is always higher than in the evaporator, the liquid in the member a will rise to a certain height dependingnpon the diflerence between the condenser pressure and the evaporator pressure. 1 Then the float will rise or fall to open or close the valve 86 as the opposed pressures in the condenser and evaporator vary. For example, if the condenser vacuum increases, that is, itithe pressure in, the condenser diminishes while the pressure in the evaporator remains the .same' the valv s will be closed to some extent because; less steam at lower pressure will thenfhe needed to evacuate the evaporator i. The sag-me result will follow if the vacuum decreases and the pressure increases in the evaporator while the pressure in the condenser remains fixed, because then at higher pressure the amount 03 vapor created in the evaporator will be smaller. On the other hand, h the absolute pressure the condenser rises, or in the evaporator it decreases, the valve is opened further to admit more steam at higher pressure to the ejector" 5. In other words more steam at higher pressure will be supplied to the ejector when the ratio between the condenser pressure and the evaporator pressure goes up, and the quantity. and pressure of the steam will be reduced when this ratio grows less.

As illustrated in Figure 1, the member Q is adjacent one end of the evaporator and the condenser and the steanf pipe 8 is bent as required at H to reach the ejector 5.

vrisesiabove the bottom thereof as shown atffii to cause enough condensate to collect on the bottom bf the condenser to fill the trap a, At its top the member 9 is joined to the evaporator by the pipe 22. L

The evaporator may consist of two or more chambers separated by partitions 23 as shown in Figure 2. In this case the steam pipe 8 will be provided with branches 24 beyondthe valves i6 and i9 and the chambers are all connected in parallel by separate vents .2 Hzo the trap member 9. Each of these'vents 25 will contains. valve 26 the stem 27 of which projects to the outside and aoaaioe tends to be closed by spring 28. Each stern has a head 29 made fast to a. diaphragm 30, forming one wall of a casing 3i connected by a pipe 32 to will not communicate with'the member 9.

With this construction ifathe apparatus is operated with all chambers and all ejectors working, and the load drops, one or moreof the chambers can be cut out simply by turning the one or more hand valves '{33 in the branch steam pipes 24, similar valves 35 in branches 35 of the return or supply pipe 2 and valves (not shown) in branches of the discharge pipe d connected to the various chambers." With '*only the remaining chambers in operation less steam and water vapor are discharged into the condenser, and the water flowing through the condenser becomes copler and the pressure in the condenser iirops.

the volume and pressure of the steam which is used; in the ejectors of the remaining chambers. The reduced load can thus be carried economically and steam is saved. When the load again increases so that more chambers in the evaporator and more ejectors have to be used again, the vacuum will become less in the condenser and the back pressure against the steam arid water vapor will be increased. The float element now opens the steam valve i6 to supply more steam athigher pressure to the ejectors. Thejfloat element it can be connected to the main valve l6 so as to make this valve responsive to' variations in load that are smaller thari the variations which take place when one or niore chambers are put into operation or put out, to permit more or less steam at higher or'iower pressures to flow through the ejectors of the chambers in the evaporators that are active.

Another function of the device is to control the system if the cooling water supplied to the condenserjto liquefy' the steam and vapor, changes in temperature. In that case the pressure inthe condenser changes and the regulating device works as before.

,Elhe valie M is thus operated by W the float elepatent to vary the amount and pressure of steam delivered to the nozzles of the ejectors accprding to the pressure difierence, or pressure ratio be: tween the outlet and inlet pressures of the ejectoEs. If for any reason the condenser pressure rises while the pressure in the eyaporator does Hence the float element operates to out idown not change, more steam at higher pressure willbe admitted to the ejectors, and if the condenser pressure falls, less steam at lower pressure will be admitted. If on the/other hand the condenser pressure remains substantially fixed and the evaporator pressure lrises as when an increase in load takes place, this means a lower pressure ratio and less resistance of the flow into the condenser. The jiralve element now cuts down-the steam as before. If on the other hand while the condenser pressure does not change, the evaporator pressure drops, a risein the pressure ratio thus occurs and the valve will then open to supply more steam as required. With this construotionz'a great saving in supply of steam in the operation of the apparatus at light loads or with cold condenser water is accomplished and the cost of operation is reduced.

To oiiset any waste of steamln case of. an increased vacuum within the evaporator I, such as will arise if there is a considerable drop in load, I. employan additional regulating device, preferably of the thermostatic type, to cut down the volume and pressure of the steam. This device comprises a bulb or the like element 36, mounted in the discharge conduit 4, and subject to the chilled water temperature thereof. It is connected by a piece of tubing 31 to suitable mechanism indicated at 38, comprising a movable rod or member 39 joined to the arm of a valve 40 similar to the valve 16, in the steam pipe 8. The valve I6 is between the valve 40 and the evaporator. Consequently, whenever the chilled water temperature drops too much, as when the load falls greatly and a considerable increase in the evaporator vacuum ensues, the larger opening of the valve l6 willbe balanced by the partial closing of the valve 40. In the bulb 36 and tube 31 will be an expansible fluid by which the member 39 will be actuated whenever the chilled water temperature sinks to a predetermined figure. A full description of this thermostatic regulator is not necessary, as various kinds known to those skilled in this art will serve the purpose. The thermostatic regulator may also be designed to respond to thermal changes in a medium other than fluid if desired. So long as the system operates above the minimum chilled water temperature selected, the valve 40 will be fully open, and the system will then be controlled by the valve i6 as described. I

In Figure 1, the valves 26, 33, 34 and ID are omitted for the sake of cleamess.

I claim.

1. The combination of an evaporator, an evacuator, therefor, a condenser to which the evacuator delivers, a member connected to the evaporator "and condenser, an element in said member connected to regulate the power medium connection of said member to the evaporator when the evacuator is not operating.

2. The combination of an evaporator, a jet- 5 operated evacuator therefor, a condenser to which the evacuator delivers, a trap member connected to the condenser and the evaporator, an element in the trap member to regulate thepower medium for the evacuator, and means controlled by the 10 pressure of said medium to cut off communication between said member and said'evaporator when the evacuator is not operating.

3. The combination of an evaporator, a jetoperated evacuator for same, a condenser to which 5 said evacuator delivers, a trap member connected to the evaporator and condenser and subject to pressure conditions in both, an element in the member connected to control the power medium for the evacuator, means for rendering said .element ineifective at starting, and means actuated by the power for the evactuator to cut off communication between the evaporator and said member when the evacuator is not working.

4. A refrigerating system comprising an evaporator chamber, an evacuator therefor, a condenser to which the evacuator delivers, means communicating with the condenser and evaporator and containing an element to control the evacuator and a connection for cutting off said chamber from said means when the chamber is not working.

5. A refrigerating system comprising an evaporator chamber, an evacuator therefor, a condenser to which the evacuator delivers, means communicating with the condenser and evaporator and containing an element to control the evacuator and a connection for cutting ofi said chamber from said means when the chamber is not working, said connections being dependent on said evacuator.

JOHN KIRGAN.

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