US2053827A - Refrigerating apparatus - Google Patents

Description

' P 9 E. J. L. HALLSTRO M 2,053,827

REERIGERAT'ING APPARATUS Filed Jan. 31, 1935 a W. m W 1 w E? H. H H W. 0 L w l 4: 9a. f w m H n m M "a 7 u A M M Y Ma 9 Patented Sept. 8, 1936 UNITED STATES REFRIGERATING A PARATUS Edward John Lees Hallstrom; Willoughby, New South Wales, Australia Application January 31, 1935, Serial No. 4,237

In Australia February 16, 1934 1 Claim.

This invention relates to improvements in refri erating apparatus, and particularly, to the in-- termittent type of absorption apparatus of limited capacity which is used largely. for domestic cool safes and the like.

In known apparatus of the class referred to in which ammonia is used as the refrigerant and is circulated throughout the system by the external application of heat alternating with the absorptive capacity of water contained in the system, attention is required to regulate the application of heat and its discontinuance at the right time. Also a certain amount of water tends to migrate with the ammonia stream to the low pressure side of the apparatus, and must be returned to the high pressure side in order to ensure satisfactory operation.

The invention consists in an absorption refrigerator of the type above indicated which is entirely automatic (save for the relighting of the burner for each cycle) requires no manual attention or manual movement of any part of it, and includes a heating element which furnishes heat at a predetermined rate and only for a predetermined time in each operation of the apparatus, means by which water which is carried from the boiler through the condenser and into the evaporator is returned to the boiler at intervals and undue accumulation of water in the evaporator is thus prevented, means by which vuncondensed ammonia gas passing out of the condenser or evaporated between the condenser and evaporator, is returned to the boiler, means whereby corrosion is inhibited on ironwork from which the galvanizing has been burnt by adjacent welding operations, an improved construction for the condenser, and a condenser cooling tank of such dimensions that it will function efficiently with convection circulation.

Apparatus embodying the invention is illustrated in the accompanying drawing, in which:-

Fig. l is a diagrammatic elevation of the apparatus in operative relation to the chamber to be cooled; and

Fig. 2 is a section to .an enlarged scale of means for preventing corrosion of metal from which the galvanizing cover has been burnt off by welding in the pipe fitting operation.

In Fig. 1, H is a reservoir of definitely limited capacity having a filling hole and cap I2 and a connecting pip-e I3 from the reservoir II to a, circular channel It forming the wick housing for the burner 15. The lowest edge 55 of the channel I4 is adjusted to be slightly higher, when erected for operation, than the highest level of kerosene or inflammable oil in the reservoir H. 16 is a wick preferably of fire resisting capillary material. The other portions of the burner 15 are of known design.

The complete heating element, which may consist of a plurality of burners l5 fed with oil from the reservoir H, directs heat on to a boiler I! having lateral heat jacketing l8 and cooling fins I9, a vapor pipe 20 carried from the boiler up a closed separator 21 and terminating at 22 under 10 a bell 23 which is supported above the top end 22 of the pipe 2%}, and has a pendent vent pipe surrounding the vapor pipe 26 and terminatingin an open end 24. From the top ,end of the separator 52! a pipe 25 is led to the condenser 2,6. 5

The condenser consists of two equal length tubes of different diameters, 2? and 28, assembled together concentrically, and closed at the ends .29 to form an annular chamber with welded joints. The condenser may consist of a plurality of sections, joined by connecting pipes 353 and may be constructed with external surfaces for air cooling, or, preferably, may be water submerged in an open topped .casing Si, in which heat is removed from the condenser by convection currents in the water.

From the condenser 26 a pipe 32 is connected to a liquor pipe 33 which extends downwardly to the top of the evaporator 34. A liquor drain pipe 35 extends from near the bottom of the evaporator 34, passing inside the liquor pipe 33 to 36 where the annulus between the pipes 33 and 35 is filled in by welding. It is not essential, but is obviously convenient and advantageous to place the pipe 35 within the pipe 33, as it is then necessary to make only onechannel 56 through the wall 'of the refrigerator chamber 58. A connection 31 extends from 38 to the separator 2|, and radiating fins 38 are fitted (welded) to this connection; the purpose .of'this feature is described below.

From the liquor pipe 33, and adjacent to the junction of the pipe 32 therewith, a gooseneck pipe 39, having the bend m at its highest point, extends down to an absorber H, and terminates at 42 near the bottom thereof, and the absorber 4| is connected to the separator 2i by upper and lower tubes 63 and 33. From the separator a tube 45, having its upper end 36 open above the level of the absorber ll extends down towards the bottom of the boiler at 31.

The refrigerator box or chamber 48 is adapted to have the evaporator 34 positioned within it, the pipe 33 being sealed against leakage where it passes through the chamber wall at 56.

Where the condenser 26 is submerged in a water tank 3| which is of thin metal galvanized to prevent corrosion, welding is necessary in order to make a watertight and rigid joint at 50, where the pipe 25 passes through the tank wall. The heat of welding burns the zinc coating off the metal adjacent to the weld, and as it is impracticable to restore a zinc coating to the metal near the weld within the tank, the thin pipe metal would rapidly corrode through at that point. In Fig. 2, 25 is the pipe, 5| the wall of the tank 3|, 52 a hole therein of larger diameter than the pipe 25, 53 is a cup welded at the rim 54 to the wall of the tank, and having its bottom perforated for and welded to the pipe 25. During the welding the galvanizing is burnt off the interior of the cup at 55. The bared surface of the cup from which the galvanizing has been lost is protected by pouring molten bitumen or other such substance through the hole 52 to fill the annulus 56.

In operation a definite quantity of suitable liquid fuel is placed in the tank II and the burners are then lighted. The system is initially supplied with ammonia and water in definite proportion and amount, sealed in, and at the begining of distillation the boiler is full of strong liquor. During distillation evolved ammonia gas passes up the tube 20, together with a small proportion of entrained water. This ascending vapor column passes into the bell 23 from the outlet 22 of the tube 20, and then passes out of the vapor tube at 24 into water which is retained at the level of the top 46 of the return tube 45; some of the entrained water is caught in the body of water in the separator. The ammonia vapor rises through the water and passes from the separator 2| through the pipe 25 to the condenser 26, still carrying with it some entrained water.

Most of the ammonia gas is condensed in the condenser, and passes as ammonia liquor with some water through the pipe 32 and the pipe 33 to the evaporator 34, where it stays until distillation ceases.

The amount of liquid fuel is adjusted by the size of the fuel reservoir tank I I as sufficient for one distillation of the ammonia contained in the system, and when the liquid fuel is exhausted the burners l5 extinguish and the boiler I! cools down, the cooling being promoted by the radiation of heat from the fins [9. The water in the boiler l1, thus cooled, becomes capable of reabsorbing the ammonia which was discharged during boiling, drawing it from the evaporator 34 through the pipes 33 and 39 into the absorber and thence into the separator and pipes 32 and 25 into the separator, and from the separator discharging at 41 into the bottom of the boiler. The bell 23 closes the opening of the pipe 22 when distillation ceases. The rate at which this absorption takes place is proportional to the rate at which heat from the refrigerator chamber passes through the walls of the evaporator 34 and evaporates the ammonia therein. When all the ammonia from the evaporator has been absorbed by the water in the boiler, the burners are refuelled and again lighted, the distillation process is then repeated.

During the distillation period, the liquor passing from the condenser 26 to the evaporator 34 carries some uncondensed gas. This separates from the ammonia liquor by gravity, and ascends the pipe 39 through the gooseneck trap pipe 40. The gooseneck bend is at a higher level than the condenser, and consequently gas passed through it is delivered into the absorber 4 I, in which water which circulates via the pipes 43 and 44 absorbs the gas and the enriched liquor passes to the separator 2|.

When distillation is complete, the liquefied ammonia fills the evaporator 34 and stands at some higher level in the pipes 32 and 39. This hydraulic head forces some of the ammonia drawn from the bottom of the evaporator 34 up the pipe 35, and through the pipe 31 into the separator 2|. This fractional purge serves to remove some of the ammonia rich in water from the evaporator, and so prevents the system from becoming water-logged in the evaporator.

The fins 38 prevent heat creeping along the metal of the pipe 31 from the separator 2! to the condensed liquor which is passing down the pipes 32 and 33 during the distillation period.

The pipe 39 may be returned to the separator, and the absorber thus eliminated, but the use of the absorber is preferable.

What I claim as my invention and desire to secure by Letters Patent is:-

Refrigerating apparatus of the kind herein described, comprising in combination, a boiler, means for applying heat thereto, a separator, a stand pipe extending upwardly into the separator and arranged to conduct vapor from the boiler to the separator and to discharge said vapor into a chamber within the upper part of the separator, said chamber having a depending tube extension, a condenser in which vapor from the separator is condensed, a pipe from the separator to the condenser, an evaporator and an absorber, a pipe arranged for passing liquid from the condenser to the evaporator, and a pipe arranged for passing vapor from the upper portion of the evaporator to the absorber, the last mentioned pipe including a loop adapted to by-pass uncondensed gas to the absorber, upper and lower connections between the absorber and the separator, a pipe arranged for passing unevaporated liquid from a low point in the evaporator to the gas space in the separator, and an overflow pipe arranged to permit return of liquid from the separator to the boiler.

EDWARD JOHN LEES HALLSTROM.

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