US2026233A - Refrigerating apparatus - Google Patents

Description

Dec. 31, 1935. J; N 2,026,233

REFRIGERATING APPARATUS Filed June 6, 1954 IN VEN TOR.

H 2Tb E'l'r an. ZZ AQQM H15 ATTORNEY- Patented Dec. 31, 1935 PATENT OFFICE REFRIGERATING APPARATUS John Kirgan, Easton, Pa., assignor to Ingersoll- Rand Company, Jersey City, N. J., a. corporation of New Jersey Application'June 6, 1934, Serial No. 729,200

1 Claim.

My invention relates to refrigerating means and particularly to refrigerating apparatus adapted to save power costs in practical operation.

In water vapor refrigeration, the water enters a vessel called an evaporator and is chilled by partial vaporization therein, the vapor being removed to be liquefied in a condenser. For the sake of discussion the evaporator and condenser are assumed to consist of a single chamber each.

The condenser is cooled by water, and whenever steam can be had at ordinary expense, to carry the vapor from the evaporator into the condenser, a steam ejector can be employed. The pressure in the evaporator is reduced enough to enable vaporization of some of the water to occur easily at a selected temperature of the incoming water. The pressure in the condenser is also low, butis greater than the pressure in the evaporator, and therefore the condenser exerts some resistance or back pressure to the admission of the steam and water vapor into it. The greater this back pressure, the more steam is required. To save steam, and at the same time obtain from the condenser water the maximum cooling effect without having to employ an excessive amount of such water, is the chief object of this invention. If the cooling water for the condenser is small in volume with respect to My aim is to produce a refrigerating apparatus that will afford economy of both steam and condenser water, and still have av refrigerating output as large as desired. Thepreferred embodiment comprises an evaporator and a condenser having several chambers each. In the evaporator the water is chilled in stages, passing from one chamber to another and the water vapor is taken out of each chamber in the evaporator and delivered to a corresponding.

chamber of the condenser.. The cooling water flows from each chamber of the condenser to the next, and its warmth is greatest in the chamber near the outlet of the waterfromthe condenser. In this particular chamber the back pressure and temperature may be somewhat high, while in the preceding chambers the back pressures and temperatures are less. Likewise, in the evaporator chamber where vaporization first takes place the pressure is highest, and it falls ofl in each succeeding chamber as the process of vaporization and chilling continues.

The steam ejectors are in multiple and so arranged that they connect the evaporator chamber of the first stage, wherein vaporization commences, to the condenser chamber of the last 10 stage which receives the cooling water just before it leaves the condenser, and so on through the series. Hence the ejectors work at successively lower intake'and discharge pressures, but the ratio of compression between each evaporal5 tor chamber and its associated condenser chamber is substantially constant.

Thus, with both evaporation and liquefaction accomplished by stages, less steam is expended than when the same quantity of water is chilled 20 the condenser used with my invention. Also a great deal-less cooling water is taken than if a condenser having one chamber is used, and the cooling water is in such amount with the inlet and outlet temperature fixed so that the back pressure in said chamber is no greater than the lowest back pressure in the sectional condenser above described. The saving in steam is of course the principal consideration, but both steam and cooling water are thus reduced to a 35 minimum.

The nature and advantages of the invention are set forth in the description that follows; but the disclosure is by way of example only, and changes may be made without departing from g the spirit of the invention or exceeding its scope.

On the drawing Figure 1 is a view mostly in section showingapparatus according to the infrom the remainder of the water to cool it, and 55 chambers of the evaporator and discharging.

into a corresponding chamber of the condenser, indicated by the numerals 3, 4' 5' and 6', the vapor in the chamber 3 being transferred to the chamber 3', that formed in the chamber 5 being forced into the chamber t, etc.

In the evaporator l chilled water to each chamber d, 5 and 6 is delivered by the chamber immediately above or ahead of it, with reference to the direction of flow through the evaporator B, through the bottom 9 by way of a delivery nozzle III, which may be of the spray.

type. A suitable delivery nozzle may also be attached to the pipe 2 inside of the chamber 3 so that the water may be divided as it enters 4 each} chamber, and thus the vaporization is facilitated. After being successively chilled in the chambers of the evaporator the water is discharged through an outlet pipe H. v

The ejectors are connected to the evaporator by means of .pipes it, one of these pipes leading to each chamber at the top thereof. These pipes communicate with the main casing of each ejector through an opening in the side thereof, and these casings receive steam through nozzles i3 connected to steam pipes It. The ejectors discharge into the chambers 3, d 5' and 6' of the condenser through ports it. .These ejectors may be of any suitable construction. The steam nozzles it are disposed so that when steam issues therefrom, the water vapor is drawn by aspiration from the chambers of the evaporator and entrained with the steam and carried into the chambers of the condenser, where the mixture of steam and vapor is liquefied. K

The chambers of the condenser are separated from one another by means of transverse partitions it and through these partitions and the ends of the condenser extend cooling pipes H which communicate with headers ill at the ends of the condenser. To one of these headers cooling water is supplied, and from the other cooling water is discharged. As shown in Figure 1, the cooling water passes in at the bottom and out at the top, cooling the chamber 6' first and the others in succession. Thus the direction taken by the cooling water in the condenser is opposite to that of the water to be chilled in its flow throughthe chambers of the evaporator. The condenser cooling water is at its lowest temperature where it enters the condenser and is warmest where it leaves the condenser. The temperature and back pressure in the chamber 6'- are therefore relatively low, but are successively higher in the other condenser chambers and greatest in the chamber 3'. But in the evaporator l the water to be cooled has its highest temperature in the chamber 3 and its lowest temperature in the chamber 6. Likewise the pressure drops in the sameway, being lowest in the chamber 6 and greatest in the chamber 3. The suction pressure .for the ejectors connected to the chambers 3, 4, 5 and 6 thus becomes successively lower and similarly the back pressure against which these ejectors work becomes successively lower in the corresponding chambers passes through the pipes 3', 4' 5' and 6'. The water vapor from all the evaporator chambers can thus be compressed by the ejectors in the same ratio as this vapor is delivered to the condenser 1. This results in a great saving of steam, as will be shown in 5 detail later.

The chamber 6' of the condenser which is first cooled by the condenser water has connected thereto a conduit I9 in the line of which is a vacuum or purge pump 20. The various 10 condenser chambers are joined by means forming vent passages 2! connecting one chamber to the next one above it, so that the purge pump 20 exhausts the various condenser chambers in series. Valves 22 in the vent passages 2| con- 15 trol the bore of these passages, so that by the action of the pump exhausting device 20, a vacuum of different degree can be maintained in each of the condenser chambers.

The various chambers of the condenser are 20 also connected by members 23 enclosing U- shaped trap passages M which connect the lower part of each condenser chamber to the top part of the next chamber beneath. Each of these passages 25 has the middle or bend 25 thereof at a lower level than the two ends of this passage. The water of condensation can drain freely from the upper chambers of the condenser down to the lowermost chamber, while at the same time these passages seal the 30 chambers from one another because of the liquid in the bends thereof. Otherwise the internal pressure of each of these chambers would be the same. The lowermost chamber has a drain pipe 25, in the line of which is a discharge 35 pump 26 to carry off the condensate from the condenser.

In operation, the pressure in the chamber 3 is so reduced by the action of the evacuator 8 that some of the water is converted into vapor 40 at once. The formation and removal of this vapor results in chilling the remainder of this water, the vapor and steam being impelled into the condenser chamber 3, while the unvaporized water is delivered into the next chamber d 45 through the nozzle ii]. In this chamber d the pressure is somewhat, lower and more water is vaporized so that the remaining water is chilled still further. The water is thus cooled by stages in the evaporator and reaches its lowest tem- 50 perature in the chamber 6, from which it is discharged through the 'pipe II.

Suppose the water delivered by the pipe 2 has a'temperature of 70 F., and the absolute pressure in the chamber 3 is about .635 inches of 5 mercury. Under these conditions enough water can be converted into vapor to bring down the temperature of the remaining liquid water to about 655 F., as it flows into the chamber I. In this chamber the pressure will be slightly lower, 60 say, about .54 inches of mercury. The water flowing from the chamber 4 into the chamber 5 will thus be cooled down to about 61 F. In this chamber 5 the pressure will be about .46 inches of mercury and the water may be cooled down 55 to about 56.5 F. Next in the chamber 6 the pressure will be, say, .4 inches of mercury and the final temperature of the water leaving the pipe II will be about 52 F.

As for the condenser, the cooling water which 70 I! will enter it at about 70 F., and be warmed to such an extent that when it leaves the other end of the condenser beyond the chamber 3' it-will have a temperature of about 98 F. In the chamber 3' the 7 back pressure will be about 2 inches of mercury, in the chamber 4' about 1.71 inches, in the chamber 5' about 1.45 inches and in the chamber 6'. about 1.26 inches. Thus as the pressure in the chambers 3, I, 5 and 6 drops, the back pressure in the respective corresponding chambers 3',

4', 5' and 6' falls also, and the load on each of the ejectors is kept down because of this reduction of back pressure in the chambers of the condenser. Therefore the water vapor taken out of each of the chambers 3, 4, 5 and 6 is compressed at about the same ratio in the condenser 1, this ratio being about 3.15. At the pressureobtained in the various chambers of the condenser the mixture of steam and water vapor will condense or liquefy at temperatures of, say, lfll, 95, 9| and 86 in the chambers 3, l, 5' and 6' respectively, and the temperature of the cooling water in each of these chambers will be below these figures, so that actual liquefaction will be accomplished.

(17.5 F.) by first reducing the pressure in the whole evaporator to .4 inches, this being the lowest pressure in the chamber 6, and all the water vapor and steam would have to be forced into the condenser at a back pressure of 2 inches of mercury absolute, which is the back pressure prevailing in the chamber 3. The compression ratio would thus be much higher and a great deal more steam would have to be consumed.

If, on the other hand, one were to try to operate the system with an evaporator having one chamber and the pressure in that chamber equal to 0.4 inches of mercury, the same as in the chamber 6, and to save steam by using a condenser with a single chamber and keeping the back pressure in this condenser down to the pressure that exists in the chamber 6', much proceeding similarly with the other chambers down to the evaporator chamber in which the pressure is lowest so that water vapor irom this last chamber is discharged into the condenser chamber wherein the back pressure is least. The operation thus proceeds step by step, therwater being cooled in successive stages in the evaporator and the vapor being removed at each stage, compressed to the same ratio and liquefied in the condenser I.

It will be seen that the apparatus achieves the ends in view by means of a comparatively simple construction, which can be readily and inexpensively built, and easily operated, and it is not likely to get out of order.

I claim:

In condensing apparatus, a series of condenser chambers within a common casin each chamber having a vapor inlet, means for passing a cooling medium through the chambers. devices having passages to convey condensate successively to each chamber and wherein condensate forms liquid seals between chambers, and means for maintaining individuality of-vacuum in each chamber and for removing non-condensible gases therefrom comprising a pump attached to an end chamber above the condensate level and distant from the vapor inlet thereof, conduits connecting adjacent chambers above the condensate levels and distant from the vapor inlets thereof whereby said gases pass successively through the chambers to reach the pump, and a valve in each conduit to control the size or orifice therein thereby to control the vacuum in each chamber by regulating the flow of gases from one chamber to a'succeeding chamber.

JOHN KIRGAN.

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