US2280051A - Refrigeration - Google Patents

Description

April 21, 1942- s. w. E. ANDERSSON REFRIGERATION 2 Sheets- -Sheet 1 Filed Oct. 1 9, 1937 INVENTOR. Jim M. F. M i12u Wm TORNEY.

' P s. w. E. ANDERSSON 7 2,280,051

REFRIGERATION Fi led Oct. 19, 1957' 2 Sheets-Sheet 2 1N VENTOR.

.atented Apr. 21,

REFRIGERATION Sven W. E. Andersson, Evansville, Ind., assignor to Srvel, Inc., New York, N. Y., a corporation of Delaware Application October 19, 1937, Serial No. 169,789

4 Claims.

My invention relates to refrigeration, and more 'articularly to control of refrigeration apparatus. .his application is a continuation in part of my pplication Serial No. 113,153, flledNovember 28, 936.

It is anobject of my invention to provide an mproved control device for controlling the heat upply of refrigeration apparatus of the absorpion type.

Another object of my invention is to provide vnimproved control device for refrigeration aparatus of the absorption type in which a valve is onnected to aimovable diaphragm andthe deice is so constructed and arranged that gas lnder pressure constantly exerts force on one ide of thediaphragm and also exerts force on he other side of the diaphragm in response-to.

emperature whereby the diaphragm is operative o flex and effect control of the valve.

The novel features which I believe to be char! .cteristic of my invention are set forth with paricularity in" the claims. The invention, both .s to organization and method, together with urther objects and advantages thereof, will be vetter understood by reference to the following lescription taken in connection with the accom- The heat applied to the generator Ill causes ammonia vapor and absorption liquid in chamber II to pass through an opening IS in the lower endoi a small vertical conduit 20 which con-' stitutes a vapor-lift and conduits ammonia vapor and absorption liquid to the upper part or the stand-pipe l3. The liberated ammonia vapor ranying drawings oi which Fig. 1 diagrarnnatically illustratesv refrigeration apparatus of in absorption type provided with a control de-' 'ice embodying my invention; Fig. 2 is an enarged vertical sectional view of the control de- 'ice shown in Fig. 1; and Fig. 3 is a fragmentary ectional view illutsrating a modification of the levice shown in Fig. 2.

Referring to Fig. l, I have shown my improved control device in connection with absorption re- 'rigeration apparatus of a uniform pressure type, :enerally as described in Patent No. 1,609,334 to 'on Platen and Munters, which contains an Tuxiliary pressure equalizing gas. The refrigeraion apparatus comprises a generator l3 having t rear chamber H and a forward chamber l2 :o'mmunicating with an upward extending stand- )ipe or separator l3. The generator contains a )ody of absorption liquid, such as water, having t suitable refrigerant, such as ammonia, in soluion therein. The generator III is heated by a :as burner H which projects its flame into the 'crward end of a horizontal flue I5 which extends hrough the generator. as is delivered from a source of supply through :onduit 16, control device I! which will be deacribed hereinafter, and conduit !3 to the urner I 4. 4

entering the stand-pipe l3 from the conduit 20, as well as the ammonia vapor expelled from solution in stand-pipe l3 and chamber I2, flows upward through a conduit 2| and liquid-cooled rectifier 22 into a condenser 26 which is shown in the form of looped coil. The refrigerant is liquefied in the condenser 26 by a, cooling medium, such as water, which circulates through a jacket 21 surrounding the condenser coil. The

liquefied refrigerant flows from the condenser 26- to the rectifier 22 so that any water vapor which may accompany the ammonia vapor isv condensed and drains back to the generator. A portion of the conduit 23 through which the cooling medium flows from the jacket 21 is arranged in thermal contact with the upper part of the conduit 2|, as indicated at 23,- .also to effect condensation of any water vapor accompanying the ammonia vapor.

The liquefied ammonia flows from the rectifier 22 through a conduit 30 into the upp r end of an evaporator or cooling unit 3| which is arranged in a thermally insulated storage compartment 32. An inert gas, such as hydrogen, enters the upper end of the evaporator 3! from. the outer passage 33 of a gas heat exchanger 34. The

A suitable combustible hydrogen with consequent absorption of heat from the surroundings of the evaporator 3 I The resulting mixture of ammonia and hydrogen, that is,-gas rich in ammonia, flows downward from the evaporator 3| through the inner passage or conduit 35 of the gas heat exchanger 34 which is connected at its lower end to the lower end of an absorber 36. The ammonia vapor in the rich gas mixture is absorbed into weak absorption liquid that enters the upper part of the absorber 36 through a vertically extending conduit 31. The heat liberated with such absorption of ammonia vapor is transferred to a cooling medium, such as water, which flows upward within a coil 38 which surrounds the absorber 36 and is connected by conduit 39 to the lower end of the jacket 21.

The hydrogen, which is practically insoluble of the evaporator 3|. The gas heat exchanger 34 transfers heat from gas which is weak in ammonia and flowing toward the evaporator 3| to gas which is rich in ammonia and flowing toward the absorber 36. a

Theabsorption liquid flowing downward through the absorber 36 in counter-flow to the gas mixture becomes enriched in ammonia and flows through a conduit 46 and inner passage 41 i of a liquid heat exchanger to chamber H of the generator ID. The liberated ammonia vapor and absorption liquid are caused to flowupward through the vertical conduit into the upper part of the stand-pipe I3, as explained above, to a higher level than it is in the absorber 36, and the absorption liquid weak in ammonia flows from the chamber l2 through conduit 42, the outer passage 43 of the liquid heat exchanger, and conduit 31 into the upper end of the absorber 36.

The lower end of the condenser 26 is connected by a conduit 44, vessel45, and conduit 46 to the gas circuit, so that any hydrogen which may pass through the condenser can flow to the gas circuit and not be trapped in the condenser. If ammonia is not liquefied in the condenser, due to changes in temperature of the cooling medium or the rate at which it flows through the condenser, for example, the ammonia vapor will flow through conduit 44 to displace hydrogen in the vessel and force such hydrogen through conduit 46 into the gas circuit, thereby raising the total pressure in the system so that an adequam condensing pressure is obtained for the increased temperature .of the condenser.

In accordance with my invention, the flow of gas to the burner I4 is controlled by the control device l1. Referring to Fig. 2, the control device il comprises a casing 41 having inlet and outlet openings 48 and 49 formed within bosses 50 and 5| to which are connected the conduits l6 and I8, respectively. A resilient or movable diaphragm 52 is secured at its peripheral edge between the two partsof the casing 41 to form an upper chamber 53 and a lower chamber 54,

and in the lower chamber 54 is provided a partition 55 having an opening to form a main passage for flow of gas from the inlet 48 to the outlet 49.

To the partition 55 at the opening therein is secured a short sleeve member 56 which serves as a seat for a valve 51 having a stem 58 secured to the diaphragm'52. The valve 51 is provided with a recess to receive the threaded upper end of a stud 59 upon which is mounted washers or weights 68 and to the lower rounded end of which is secured a removable snap-on button or spring clamp 6|.

The spring clamp 6| is adapted to bear against a thermal element arranged at the lower end of the casing 41. This thermal element comprises a resilient diaphragm 62 secured to the peripheral edge of a plate 83 which in turn is secured between the lower end of the casing 41 and a cover plate 64. At a central opening in the plate 64 is secured one end of a tube 65 which extends through an opening in the cover plate 64 andis connected at its other end to a thermal bulb 66 which is arranged in thermal contact with the liquid cooled rectifier 22, as shown in Fig. 1.

The resilient diaphragm 62 and plate 63, tube 65, and bulb constitute an expansible fluid thermostat which contains a suitable volatile fluid that increases and decreases in volume with corresponding changes in temperature. The resilient diaphragm 62 moves toward and away fromthe valve openingwith an increase and decrease in volume of the volatile fluid, and these movements of the diaphragm 62 are utilized to regulate the valve 51 and control the flow of gas to the burner M, as will be,dcscribed hereinafter.

The upper part of the casing 41 is provided with a'pa-rtition 61 which forms the extreme upper chamber 68 and, with the diaphragm 52,

forms the intermediate chamber 53. The casing 41 is provided with a by-pass passage to permit gas to enter the outer'chamber 68 from the main gas passage formed by the lower chamber 54. The flow of gas from the chamber 68 through an opening in the partition 61 and into the chamber 53 is controlled by a, valve 18 which is urged to its closed position by a resilient leaf spring 1| s cured to the underside of the partition 61. The casing 41 is provided with an opening communicating with chamber 53, and at thisopening is secured a conduit 13 which terminates in the vicinity of the burner H, as shown in Fig. l.

The valve I6 is provided with a triangularshaped stem 14 having an enlarged head I5 which is adapted to bear against a thermal element 16. This thermal element comprises an expansible diaphragm which is secured to and in open communication with a hollow hub member I1 to which is connected one end of a tube 18, the other end of which is connected to a thermal bulb 19 arranged in thermal contact with the evaporator 3|, as shown in Fig. 1. The hub member 11 is mounted on a resilient diaedge between the upper end of the casing 41 and -a cover plate 8| having an opening through which the tube 18 passes. The cover plate 8| is provided with an adjustment screw 82 for adjusting the position of the resilient diaphragm 88 and hence the position of the expansible diaphragm I6.

The expansible diaphragm l6, tube I8, and

bulb I9 also'eonstitute an expansible fluid thermostat which contains a suitable volatile fluid that increases and decreases in volume with corresponding changes of temperature. The expansible diaphragm l6 expands and contracts with an increase and decrease in volume of the volatile fluid, and these movements are transmitted to the valve 10 to control the flow of gas from the outer chamber 68 into the intermediate chamber 53.

The structure which is disposed in the chem-- bers 53 and 68 and just described is capable of regulating valve 16 toefiect control of the valve 51 and hence the flow of gas to the burner l4, so that the evaporator or cooling unit 3| of the refrigeration apparatus will be capable of maintaining the storage compartment 32 at a. desired low temperature. When the evaporator 3| tends to rise above the desired low temperature. the volatile fluid of the expansible fluid thermostat increases in volume and causes the expansible diaphragm I6 to expand whereby the enlarged head 15 againstwhich it bears is moved downward and causes the valve Hi to open against the action of the leaf spring Under these conditions, gas flows from the chamber 54 or the main gas passage through the passage 68, chamber 68, and open ng in the partition 61 into the chamber 53.

.When the gas pressures in the chambers 58 and N are substantially the same and the forces.

" perature or boiling point, so that refrigerant is vaporized and expelled out of solution from the absorption liquid. With the burner flame of such size that refrigerant is expelled out of solution from absorption liquid, the refrigeration apparatus operates in the manner described above to produce cold in the storage compartment 32. The gas flowing into the chamber 53 during the periods the valve I0 is open is conducted therefrom through conduit ll to the vicinity of the burner I4 and augments the heating of the gen-,

erator l0 effected by the burner.

When the evaporator ll tends to fall below the desired low temperature, the volatile fluid of the expansible fluid thermostat becomes reduced in volume and causes the expansible diaphragm I8 to contract, whereby the resilient leaf spring II becomes effective to urge the valve 10 to its Under these conditions, the

closed position. chamber 51 is substantially at atmospheric pressure and the pressure in the chamber M or main gas passage is the same as that in'the gas supply conduit ll. Since the force now exerted on the under 'side of the diaphragm 52 is considerably greater. than that exerted on the top side of the diaphragm, the resultant force exerted onthe diaphragm will-cause the latter to move upward and also move the valve toward its closed position. The load on the diaphragm 52 effected by the weights or washers M is preferably such fluid increases in volume and causes-the resillent diaphragm II to expand and move upward.

'With such upward movement of the resilient diaphragm G2 the valve "51 is moved to its closed position irrespective. of the resultant force exerted on the diaphragm by gas under pressure in the main passage or chamber 54. When the valve 51 is caused to move to its fully closed position in response to a predetermined rise of temperature, the supply of gas to the burner H is shut off completely, whereby heat is no-longer applied to the refrigeration apparatus.

If desired, means other than weights or washers ill may be employed to load the diaphragm S2 to adjust the rate of flow of gas to the burner during the periods when the burner. is operating under a minimum flame" condition.- Further, a relatively small movementof the expansible diaphragm 16 to effect movement of the valve ll produces a much greater movement of the movable diaphragm 52 and'main valve 51 connected thereto, so that a sensitive control of the that during normal operation valve 51 will not move to its completely closed position when valve III is cl0sed,but will assume such a position that as flows to the burner at areduced rate whereby heat of liquid is supplied to the refrigerant and the refrigerant is heated to a temperature slightly below its vaporization temperature. Since refrigerant is not expelled out of absorption liquid under these conditions, cold is not pro- 'duced in the storage compartment 32 by the evaporator ll.

When the evaporator 3| again tends to rise above the desired low temperature, the valve "I0 is opened. to vary the resultant force exerted on the diaphragm 52 and effect movement of the valve 51 toward its full open position, as described above. It will now be understood that the control device is so constructed and arranged that the gas under pressure in the chamber 5! flow of gas to burner I4 is obtained. I

When valve II is closed, gas is delivered to burner I at a minimum pressure with valve 51 in its uppermost position. The force exerted by gas on the under side of diaphragm 52 is balanced by atmospheric force on the upper side thereof and the total weight on the-diaphragm including'valve 51 and the loading means 50.

With any changes in gas line pressure, the control device l1 under these conditions actsasa pressure regulator to maintain the minimum gas delivery pressure substantially constant. When the gas linepressure atinlet 48 increases, for exampleythe gas pressure in chamber 54 tends to increase and move diaphragm 52 and valve 51 upward, whereby the flow of gas past valve 5! is reduced. The valve 51 assumes a new position for, the increased vgas linepressure when the forces exerted on opposite sides of diaphragm 52 are balanced. In this new position of valve 51 the gas pressure on the under side of diaphragm 51 is the same as it was before an increase in gas line pressure tookiplace, whereby to I or main gas passage constantly exerts force on one.side of the diaphragm 52 and also exerts force on the other side 'of'the diaphragm in response to change of temperature from a predetermined value to cause flexing of the diaphragm and hence control the valve 51.

The valve 51 controls the flow of gas to the burner ll in response to the action of the thermal element 82 as well as the action of the thermal element 18 If for any reason the temperature of the liquid-cooled rectifier 22 becomes relatively high, due to failure of thelcooling mediumto circulate through the pipe 21 surrounding the condenser 25, for example, the volatile mum gas delivery pressure.

Similarly, when the gas line pressure decreases at inlet ll, the gas pressure on the under side of diaphragm .52 tends to decrease so that the diaphragm and valve -51 move downward andv the flow of gas past valve 51 is increased. The valve 51 assumesv a new. position for the reduced gas line pressure when the forces exerted on opposite sides of the diaphragm are again balanced. In this new position of valve 51 the gas pressure 'in chamber 54 is again the same as it was before a reduction in gas line pressure took place, whereby gas is delivered to burner H substantially at the'sa'me minimum gas pressure.

The above gas pressure regulation also occurs whenever valve I0 is not fully open arid the latter effects a pressure differential. In other words, whenever valve 10 is not fully open and the gas pressure in chamber 53 is less than that in chamber 54, valve 51 is capable of moving toward and away from its closed position with changes in gas line pressure to maintain the gas delivery pressure substantially. constant for each particular position that thermal element 16 causes valve 51 toassume.

The above described gas pressure. regulation is possible when valve I0 is closed, or only partly open and effects a pressure differential, because diaphragm 52 is capable of moving valve 51 ter effects no pressure differential.

toward its closed position when the gas line pressure increases. When valve is fully open, however, no pressure differential is eifected between chambers 53 and 54 with valve 51 fully open;

With valve 51 fully open and gas being delivered to burner l4 at maximum pressure, therefore, no 1 gas pressure regulation occurs because the gas pressures on opposite sides of diaphragm 52 will always remain substantially the same irrespective of changes in gas line pressure.

In Fig. 3 Ihave shown a modification of the control device II of Fig. 2 whereby the maximum pressure at which gas is delivered to burner 14 may be maintained substantially constant even when valve In is fully open. In this modification in the by-pass passage, whereby the gas pressure in chamber. 53 will be less than that in chamber 54 even when valve 'I0 is fully open and the lat- 51 is fully open the force exerted by-gas in chamber 54 on the under side of diaphragm 52 is balanced by the force exerted by gas in chamber 53 on the upper side of the diaphragm and the weight on'the latter including the valve 51 and loading means 60. Since the gas pressure in chamber 53 is less than in chamber 54, any increase in gas line pressure will permit diaphragm 52 to move valve 51 toward its closed position to reduce the flow of gas past valve 51. Conversely, when the gas line pressure decreases, the gas pressure on the under side of diaphragm 52 When valve.

Ill is in its full open position, thereby making unnecessary the provision of a seperate gas pressure regulator.

' one side to pressure of gas on the outlet side of said valve and operatively connected to said 'valve so that said pressure acts toward closure of said valve, a predetermined load acting on said valve toward opening of said valve whereby said valve is constantly maintained in a, position such that said pressure balances said load, and

means to place additional load on said valve to v increase said pressure comprising a conduit for tends to decreasewhereby the diaphragm and valve 51 move downward to increase the flow of gas past valve 51. The valve 5! assumes a new position for the increased or reduced gas line pressure when the forces exerted on opposite sides of the diaphragm 52 are balanced. In such newposition of valve 51 the gas pressure in chamber 54 is substantially the same as it was before the increase or reduction in gas line pressure took place, whereby gas is delivered to burner l4 at a substantially constant maximum pressure.

When valve H! is fully open, therefore, the

- pressure differential in chambers 53 and 54 is effected by valve 33 to provide gas pressure regulation when gas is delivered at a maximum pressure to the burner l4. When valve I0 is partly open, both the valves 10 and 83 eifect a pressure difierential in the chambers 53 and 54 to provide gas pressure regulation. -The valve 83 may be adjusted to any desired position to adjust and conducting to atmosphere gas from the outlet side of said valve, the other side of said movable member being subjected to pressure of gas in said conduit, said conduit providing a predetermined resistance to gas flow to atmosphere, arelay valve in said conduit, and a thermostat operatively connected to said relay valve so the latter assumes any position between and including its open and closed positions depending upon the temperature to which said thermostat is subjected.

2. A control device as set forth in claim 1 in which there is another adjustable valve in said conduit and adjusted to restrict flow of gas so that pressures cannot equalize on opposite sides of said diaphragm regardless of the operating position of said relay valve.

3. A combined gas pressure regulator and, control device for controlling flow of gas and regulating the pressure of such gas delivered to a burner, said combined regulator and control delimit the pressure on the upper side of diaphragm 52 to a certain percentage of the gas pressure chamber 54, thereby retaining part of the balancing lifting force of diaphragm 52.

In view of the foregoing, it will now be understood that valve 51 is normally controlled by explansible diaphragm I5 which controls the flow of gas in by-pass passage 53 and hence regulates the' diiferential of gas pressures in chambers 53 and 54. By providing the valve 83 in the bypass passage, as shown in Fig. 3, the control device is also operative to regulate the pressure of gas delivered to burner l4 even when valve valve for controlling the opening and hence the flow of gas between the inlet and the outlet, a diaphragm operatively connected to said main valve and at the discharge side of the opening, structure including said diaphragm forming a chamber at the opposite side of said diaphragm from said partition, said casing having a passage to divert to said chamber gas fiowing between the inlet and outlet, an auxiliary valve to control flow of gas through said passage to said chamber, said casing having an opening to permit venting of gas from said chamber whereby the latter is substantially at atmospheric pressure when said auxiliary valve is closed, and means responsive to pressure for operating said auxiliary valve so the latter assumes any position between and including its open and closed positions depending upon the pressure to which said last means is subjected.

4. A device for controlling fiow of gas to a burner comprising a casing having an inlet and said casing responsive to pressure for operating 10 said auxiliary valve, a second expansible and cqntractible' member at the opposite end of said casing responsive to pressure and arranged to close said main valve irrespective of the control exercised by' said first expansible and contractible member oversaid main valve, and said main valve, auxiliary valve and both of said expansible and contractible members being substantially in alignment within said casing.

SVEN W. E. ANDERSSON.

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