US1754967A - Refrigerating system - Google Patents

Description

April 15, 1930. A. c. SCHICKLER REFRIGERATING SYSTEM Filed June 30, 1927 Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE ALBERT C. SCHIGKLER, OF CLEVELAND, OHIO, ASSIGNOR T EDMUND E. ALLYNE, OF

CLEVELAND, OHIO REFRIGERATING SYSTEM Application filed June so,

This invention relates to refrigerating apticularly to the type shown in my prior applications for refrigerating system filed October 27, 1926, Serial No. 144,461, and November 15, 1926, Serial No. 148,501.

The present invention has for its object to provide a system. of this kind which is reliable in operation because of the provision of improved means for initiating and carrying on a cooling effect in the boiler during the absorbing phase of the cycle, whereby a proper production, distribution and balance or lack of balance of pressures at the end of the heating period positively introduces the returning gas to the still in a manner to ini-- tiate and promote absorption and at the same time expedite and foster the cooling of the absorbing agent.

A further object of the invention is to provide a system of this kind with a proper arrangement and distribution of one way flow controlling devices, such as traps, so that when the cycle shifts from the heating to the absorbing phase, the drop in pressure at the condenser becomes fully effective in the boiler for producing a positive flow thereto from the evaporator of the gasified refrigerant, with concurrent absorption to foster and promote additional gas flow,

A further object/of the invention is to provide a system of this kind in which the absorbing agent, during the refrigerating, cycle, is cooled by its circulation to and through a quantity of cooling agent, such as water, by means of a loop or return bend of special form, together with means for shielding said loop or so permitting or preventing a cooling efi'ect on parts thereof as to enable the returning gas to be used to initiate circulation through the loop and promote it while it is later carried on by the heat interchanging process.

Still another object of the invention is generally to improve the cooling loop by shielding one of its legs from the cooling agent and exposing the other thereto, thereby furnishing hot boiler liquid for receiving the bubbles bf the returning gas and promoting circulation for boiler cooling purposes.

1927. Serial No. 202,724.

Other objects of the invention are in part obvious and in part will appear more in detail hereinafter.

In the drawings, which represent one suitable embodiment of the invention, Fig. 1 is a diagram of the complete'system; and Fig. 2 is a sectional elevation through a one way flow controlling device.

.The refrigerating system shown in the drawings comprises a still or boiler 1 in which the refrigerant, such as ammonia or the like is distilled from the absorbing agent, such as water, during the heating operation and is absorbed therein during the refrigerating phase of the cycle, a condenser 2, a receiver 3 and an evaporator marked generally 4, all connected in a circulation system by conduits of proper size and form, the entire system being sealed against any escape of gas to the atmosphere or penetration of atmospheric air to its inner chambers or passages. The system shown for purposes of illustration is of the one way type in which the gas distilled in the boiler flows to the condenser, is there condensed as a liquid, is delivered to the receiver and from there is discharged into the evaporator, all during the boiling period. During refrigeration the gas now generated in the evaporator travels back to the boiler by a separate path.

As shown in the drawings, the gas distilled in the boiler 1 is discharged from its top by a pipe 5 leading to the rectifier 6 which is water jacketed for cooling purposes and is arranged to drain back to the boiler any absorbing agent which may be carried over entrained in the gas. From the top of the rect-ifier a pipe 7 leads to a one way flow con trolling device 8, of any suitable form, adapted to permit flow toward the condenser but not in the reverse direction and which, for example, may be the type of mercury trap shown and described in my prior applications above referred to. From said mercury trap the gas flows by pipe 9 to the condenser 2 and thence downwardly through the same to its bottom and thence to a fairly high loop or pipe return bend 10, the purpose of which will later appear, and the second leg 10 of which loop communicates at its botthe gas is conducted by a pipe to the loop or return bend 16, the two legs of which are connected to the still or boiler 1 so that the absorbing agent or liquid therein can circulate through the loop. From the bottom of the evaporator a pipe drains to the pipe 13 by way of a one way flow controlling device 41, for the purpose of maintaining a head of useful liquid refrigerant in the evaporator, but permitting the return to the boiler of weak liquor which would otherwise collect in the evaporator. The device 41 may be of the same general form'shown and described in either of my said prior applications and requires no detailed description.

For cooling purposes any suitable arrangement may 'be'used. It is desirable -to cool the loop 16, the rectifier 6, the condenser 2 and the receiver 3 and for this purpose these four parts, or any group thereof, maybe separately provided with cooling means, such as separate tanks of water, either stagnant or circulating. In the arangement shown in the drawin s all four of the parts 16, 6, 2 and 3 are coo ed by the same cooling agent. The condenser 2, receiver 3 and part of the loop 16 are immersed in water or-other suitable cooling agentsupplied to a tank 17 through pipe 18. Tank 17. may be sealed and the water may be introduced into the bottom thereof, being delivered from its top by a ipe 19 to the jacket 20 around the rectifier, rom which the water is led through a pipe 21 to the sewer or to some cock in the plumbing system of the house or building in which the refrigerating system is located, such as the faucet 22. \Vith this arrangement, by giving the tank 17 sufiicient capacity, the normal daily withdrawal of water from the faucet 22 for domestic use provides suf-- ficient change in the cooling water in the tank 17 and jacket 20 to accomplish all necessary cooling purposes, but, if desired, the discharge pipe may be open to the sewer and a smal quantity of cooling water may be permitted to flow continuously, or the cooling water tank may be provided with an overflow pipe 50 to the sewer controlled by a thermostatic valve indicated conventionally at 51 and adapted to open and permit overflow when the temperature rises unduly and to close when the temperature drops to an efficient condensing tem erature.

The boiler may be eated in any suitable manner, such as by electricity or the circulation of steam around or through coils within the boiler, or, as shown, by the gas burner 23.

i/ The loop 16 has two legs, both communitilling operation by the heat conducted along the pipe from the boiler. At the bottom of said leg is a depending bulb or enlargment 16", which functions somewhat like avermiform appendix, in that it provides a collector for stray foreign matter, such as metal chips or oxide, which might otherwise clog restricted parts or passages or some of the circulating pipes. All such foreign matter in time finds its way to this bulb form trap. The second leg 16 of the loo is curved with an immediate or direct rise roni its bottom, followed by a lateral extension, giving it fairly considerable length of contact with the cooling'water, as well as a gradual rise toward the boiler, its horizontal extent reducing the rate of rise and thereby retarding upward flow of gas and promoting delayed intimate contactbctween the gas and absorbing agent during cooling of the latter. It may be provided with heat radiating means such as the washer-like fins 16 and the metal plate 16 which are merely metal parts welded or otherwise connected to the metal of the pipe and which promote transfer of heat to and from the cooling water.

The pipe 15 enters the loop where the leg 16 begins to rise and at a point fairly close to the bottom of the jacket 24, for a purpose which will later appear.

While the traps 8, 11, 14 and 41 may be of any suitable form, such as those in my prior applications referred to, I have provided an improved form of said traps whlch forms the subject matter of a separate application and is there claimed. Briefly described, and referring to Fig. 2, said trap comprises a sealed metal shell 25 into which vertical and horizontal pipes 26, 27 extend, the former extending through a hollow dome 28 to the bottom of the trap, where its sides are slotted out to provide small openings 29 affording communication from the pipe channel to an inner chamber 30 communicating by bottom slots 31 with an annular chamber 32 in the shell. Dome 28 is also provided with a relief port 33. The closed end of pipe 27 lies fairly close to the pipe 26 and is provided with a port 34 just above the roof of the dome and baflled thereby.

The normal mercury level is indicated by thedine A, just a little above the openings,

29, and the arrangement in effect is a 'U-tube,

" with two columns of mercury in,,communieating legs. Gas flow from the pipe :26 to-. ward the pipe 27 finds but slight resistance because the depression of the column or leg gas of mercury in pipe 26 until gas. escape is afforded through the openings 29 does not n'iateria-lly raise the level ofthe mercury leg in the chambers 30 and 32, but gas flow in the contrary direction finds a very heavy resistance. due to the fact that depression of the column of mercury in the chambers 30 and 32 must raise a high column of mercury in the pipe 26 before the gas can pass through the ports 29. As in my prior applications the trap is so arranged that as it is physically inverted the mercury follows the outer walls and is prevented from possible escape through the ports 29 and 34.

The ports 33 and 34 are approximately the same size for the purpose of maintaining equalization of pressure in the two chambers 30. 32 and thereby preventing any sudden rush of gas carrying mercury with it into and through the conduits. For example, as gas fiows from pipe 26 through the ports 29 into chamber 30, it passes from thelatter chamher through the port 33 into chamber 32 but cannot issue from the latter chamber through the port 34 any faster than it enters through port 33, as a result of which the pressure on the mercury columns in the chambers 30, 32 is maintained uniform with no tendency to blow or sweep the mercury out of the trap. The same effect is true in the case of gas flow or attempted flow in the contrary direction. As an added precaution or guard the pipe 26 above any trap may be provided with a baffling enlargement or well .35 similar to those shown in my said prior application Ser. No. 148,501, although this is not always essential.

In the system described, when distillation occurs in the boiler, the gas is rectified at the rectifier 6 and passes through the trap 8 to the condenser, where it is condensed into liquid form. During the heating operation the pressure in the boiler rises. The liquid collects in the condenser and thereby reduces its condensing capacity to a point Where it is incapable of condensing all of the gas being supplied to it from the boiler. The rise in 1 pressure therefore forces the liquid out of the bottom of the condenser and up into the high loop 10 until finally the crest of the loop is surmounted and from then on the operation proceeds by a sort of fluttering or self-governing action with more or less intermittent discharges of liquefied gas over the crest of the loop 10 as the pressure in the boiler rises and the condenser more or less [fills up. The liquid passing over the loop 10 gravitates to the receiver in which it collects and in which it is held for later delivery to the evaporator. Of course, the liquid in the boiler flows toward the evaporator until it fills the pipe 15, but with no possibility of flow of liquid upwardly in the pipe 13 due to the trap 14. Also, during distilling, there is no circulation through the loop 16, but the liquid therein remains quiescent.

When the greater portion of the gas has been distilled from the boiler the pressure has risen to possibly 150 pounds, more or less, and the boiler temperature is at say 260 F. Thereupon, the heater is extinguished and boiler distillation ceases.

The boiler continues to give off gas as the liquid therein absorbs heat from the superheated boiler shell, and the condenser continues to condense, because it is still losing heat to the cooling water. This condensing action continues until the boiler pressure has been reduced below the condensing pressure. This low pressure in the condenser is equalized directly to the boiler and through the return gas line 15, 13 is freely transmitted to the evaporator. shutting off of the heat, the trap 11 ceases to function in the sense that there is no further flow through it toward the evaporator, because the condenser is capable of condensing more rapidly than the boiler is capable of I w r l 1 i giving otl gas. lhcl efoie, at this point the trap 8 continues to pass gas from the rectifier to the condenser, but the trap 11 is locked, as it were, preventing back flow toward the condenser. The boiler and evaporator are at substantially the same pressure and the an hydrous ammonia in receiver 3 is tending to maintain the pressure which prevailed at the instant the heat was shut off.

i As the pressure in the boiler and evapora tor is reduced by continued condensation in the condenser, the liquid in the receiver, in its attempt to maintain the pressure begins to gasify. The gas thereby generated encounters heavy resistance at the mercury seal in trap 11 and forces mercury up into the vertical pipe 10" in quantity sufficient to counterbalance the head of anhydrous ainmonia in pipe 12 from the bot-tom of the receiver to the top of the evaporator, until finally the expanding gas forces the liquid refrigerant over the crest of the pipe 12 into the evaporator. The pipe 12 must be of fairly small diameter to prevent the passage of gas past the liquid with consequent waste of useful anhydrous ammonia. During the transfer of liquid through pipe 12to the evaporator the pressure in the boiler and evaporator has still further reduced and the pressure differential between the receiver 3 and the evaporator 4; has increased. Consequently the mercury is driven higher inpipe 19*, which is high enough to counteract this differential and prevent any possibility of the back pressure driving themercury from trap 11 over the crest of the bend 10 toward the condenser and thereby permitting it to permanently escape from its proper position in the system. The action continues until the receiver 3 completely empties itself into the evaporator.

Immediately upon the v With the release of the back pressure of the column of liquid in pipe 12, the gas in receiver 3 behind the liquid finds a free outlet to the evaporator and thence through pipe 13, trap 14 and pipe 15 to the loop 16 and the surge of gas into said loop initiates circulation of the liquid therein. The initial impulse is continued by additional gas generated by the anhydrous ammonia in the evaporator, so that the original pressure is maintained against a ten or fifteen pound drop in the boiler; the circulation of the liquid within the loop is continued; and as the boiler temperature lowers and the returning gas is absorbed in the liquid now being circulated through the loop, the boiler pressure continues to drop and continue the absorbing action.

At about this time the additional anhydrous ammonia left in the condenser at the instant of shutting off the heat, together with the additional condensation up to the time when the condenser pressure has dropped below the pressure necessary for condensation, begins to exert pressure against trap 8. Its exit in this direction is closed by the mercury seal and this anhydrous ammonia immediately begins to expand as it did in the receiver and thereby forces the liquid over the bend 10 into the receiver 3 and thence through the pipe 12 to the evaporator, so that finally all of the condensed liquid is delivered to and is permitted to expand in the evaporator for useful refrigerating effect.

The gas is delivered into the loop 16 on the rising leg very closely adjacent to the bottom of the heated leg 16. The effect of gas entering from ipe 15 is to produce upward travel of liquid in the leg 16 and the more the liquid travels upwardly therein, the more rapidly does hot liquid flow down leg 16 and thence into the cooled leg 16. It is desirable to maintain a circulation of liquid through the loop 16 from the leg 16 to the leg 16 and thereby to keep this circulating column hot while starting, so as to initially retard absorption, permitting the gas bubbles to rise in the liqliid column before they are fully absorbed, thereby assisting and expediting circulation. Obviously, circulation of the liquid in the boiler through the loop 16 per mits the absorbing agent to be cooled for the purposeof increasing-its absorbing ability :nd of carrying on subsequent loop circulaion.

In practice it has been found that the initial suction effect produced by continuing condensation in the condenser and by properly trapping the flow is suflicient tostart the loop practically immediately when the heat is' cut off, and with boiler circulation thereby started is suflicient to produce an increasing absorbing effect so as to carry on the process so long as gas is generated in the evaporator and until the boiler is again heated.

What I claim is:

1. Absor tion refrigerating apparatus, includin a boiler absorber, a cooling loop throug which the refrigerant and absorbing agent ma circulate, said loop having two legs, one shie ded from and the other in heat conducting relation'with a cooler, and a gas return flow connection communicating with the heat conducting leg of said loop.

2. Absorption refrigerating apparatus of the type specified in claim 1, in which the cooled leg of said loop is provided with a rapidly rising portion followed by an extended gradually rising portion, said gas return flow connection communicating with said rapidly rising portion.

3. Absorption refrigerating apparatus, comprising a still-absorber provided with a cooling 100 through which the refrigerant and absorbing agent may circulate, a condenser and an evaporator, a one-way flow connection from the still to the condenser and evaporator, said cooling loop having two legs one shielded from and the other in heat conducting relation with a cooler, and a oneway gas return flow connection from the tlavaporator to the heat conducting leg of said 4. Absorption refrigerating apparatus of the type specified in claim 3, in which the cooled leg of said loop has a rapidly rising portion followed b an extended gradually rising portion, sai return flow connection communicating with said rapidly rising portion.

In testimony whereof I hereby afiix my signature.

ALBERT C. SCHICKLER.

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