US2337067A - Safety device for absorption refrigerators - Google Patents

Description

1943- R. E. scHuRTz El'AL 2,337,067

SAFETY DEVICE FOR ABSORPTION REFRIGERATORS v Filed Dec. 12, 1940 2 Sheets-Sheet l Dec; 21; 1943- R. E. SCHURTZ ETAL 2,337,057

: SAFETY DEVICE FOR ABSORPTION REFRIGERATORS Filed Dec. 12, 1940 2 Sheets-Sheet 2 name use; 21. 1943 UNITED srAr-Es P-ATENr OFFICE sum DEVICE roa ansoamon anrardaaa-roas,

tion of Michigan Application December 12, 1940,; Serial No. seas-1s 14 Claims. (ores-) This invention relates to a safety device for absorption refrigerators, and more particularly to a single device responsive to any one of a number of abnormal conditions in a continuous absorption refrigeration system 'to hut offfuel flowto a burner.

One feature of this invention is that it provides complete safety for an absorption refrigeration system left uninspected for considerable periods of time; another feature of this invention .is that a single safety device replaces a number of independent and completely separate safety devices previously used; afurther feature of this invention is that it converts pressures into mechanical force and balances these forces in such a way that any abnormal increase or decrease of any or all of these pressures effects actuation of the safety element; other'features and advantaxes of this invention will be apparent from the following specification and the drawings, in which:

Figure 1 is a schematic diagram of a refrigeration system with which this invention flndsparticular use; Figure 2 is a top plan view, partly broken away, of the safety device shown diagrammatically at the bottom of Figure 1; Figure 3 is a vertical sectional view along the line 3-3 of Figdevice; and Figure, 5 is a horizontal sectional view along the line 5-5 of Figure 1.

While the safety device particularly illustrated herewith is adaptable to a number of different uses and systems, it has been found particularly useful in connection with a continuous absorption refrigeration system, such a system being shown schematically in Figure 1. In order to better understand the operation and advantages of the by any convenient means, as the burner il, supplied with fuel, as gas, through the conduit l2.

Refrigerant vapor passes up the pipe I3, through a water-cooled rectifier it, to a water-cooled condenser I 5. The condensed refrigerant vapor then 7 passes upthrough the pipe It to a receiver i'l where an expansion-valve, here shown as of the conventional float actuated type, controls its admission at greatly reduced pressure to the evaporator or cooling coils l8. The expanded refrigerant vapor then passes through a check valve i9 and bubbles out into weak liquor in the absorber' 20. Cooling water admitted through the pipe 2| cools the condenser l5, passes through a,

cooling coil 22 in the absorber, next flows through the rectifier l4, and is finally discharged through the pipe 23.

In order to keep the proper quantity and concentration of liquor in various parts of the system it is necessary to have some flow path betweenthe absorber and the still to deliver weak liquor to th absorber .and return rich liquor to the still. Since movement from the still to the absorber is from a high pressure to a low pressure portion of the system, this may be conveniently effected. It is here accomplished by passing weak liquor out through a pipe 23, through ure 2; Figure 4 is an end elevation of the safety safety device the entire refrigeration system will be described briefly. It will be understood, how? ever, that the present application is directedprimarily to the-safety device and that other features and improvements of'the ystem are more particularly disclosed and claimed in our othercopending joint and sole applications, the earlier flied of such applications being Serial No. 298,110,

flled October 5, 1939; Serial No. 296,995, 'flled September 28, 1939; Serial No. 314,704, filed January 19, 1940; Serial No. 319,541, filed February 17, 1940; Serial No. 326,292, filed March 27, 1940; and Serial No. 352,328, filed August 12, 1940.

Referring now more particularly to Figure 1, the refrigeration system schematically illustrated is particularly designed for commercial work. A still l0 contains a mixture of refrigerant and absorbent, a ammonia and water, and ismheated snap-acting mechanism better shown in Figure 5 the coil 24 in the heat exchanger 25, through the pipe 26, the valve assembly 21, and the pipe 28 into a pan in the top of the absorber, overflow from this'pan replenishing the main body of liquid in the absorber. In order to effect an interchange of liquid between the absorber and still when the concentration in the still has boiled down to a desired minimum strength a fluid thermostat bulb 29 deliver pressure generated in it through a liquid actuating leg 30 to a bellows chamber in the actuating part of the valve assembly 2]. Here pressure in the actuating leg is balanced against still pressure delivered through the pipe 23 and the valve controlling flow from the-pipe 26 to the pipe 28 opens and closes at appropriate intervals.

The return circuit from the absorber to the still is somewhat more complex. When the level.

of liquid in the absorber reaches the overflow point 3| it drains down past the check valve 32 through another valve assembly 33, and through the pipe 34 into a transfer chamber 35. A float 36 in the transfer chamber is operated through to actuate a rod 31 in the pipe 3| to move the valve: member in the valve assembly 33, which may be of the plunger type.

In one setting of the valve in the unit 33 the the snap action mechanism pipe 38 is connected to the pipe 34, as before described, to permit flow of liquid into the lower part of the transfer chamber; and the pipe 39 is connected to the pipe 46 to vent gas from the top of the chamber to the absorber. When the chamber has practically filled the upward movement of the float snaps the actuating rod 31 up to the position shown in the drawings, and in this position pipe 4| leading from the bottom of the transfer chamber is connected through the valve unit 33 to pipe 42, the flow path proceeding through the heat exchanger 25, the pipe 43, a jacket 44 around the thermostat bulb 29, and thence into the body of liquid already in the still. In order to equalize pressure in the transfer chamber and permit a gravity fiow of liquid in this position of the valve the pipe 39 at the top of the chamber is connected to the pipe 45 which is open to high pressure vapor in the pipe [3, being in communication with it at the latters entrance to the condenser l5. As the liquid drains out of the transfer chamber and back to the still the float 36 drops until the point is reached where is unbalanced, whereupon the rod 31 moves down to its lower position placing the transfer chamber in communication with the absorber to refill it.

In order to accomplish the desired snap action so that the valves in the unit 33 will never be in an intermediate position, and referring particularly to Figures 1 and 5, it will be seen that the float is connected by a link 46 to a fork member 41 pivoted at 48. The ends of the legs of the fork 41 are pivoted at 49 to a smaller fork member 50, the actuating rod 31 being pivotally connected to the apex of this latter fork member. A coil spring has one end fastened to the apex of the fork member 56 and the other end to an appropriate point on the wall 52, the spring being under tension at all times. It will be readily apparent that when the fioat is in the position shown in Figure 1 the spring 5| will maintain the actuating rod 31 and the plunger at the top of it at the top of its stroke. As the float 36 falls in the chamber with discharge of liquid therefrom the position of the actuating rod will not change until the pivot points 49 connecting the two fork members have passed up slightly above the center line of the spring 5|; but as soon as this takes place the spring will become effective to pull the actuating rod 31 and the plunger valve moved thereby to the lower end of ,their stroke.

As has been heretofore said, other features and improvements in the system in general are the subject matter of earlier filed copending applications and other applications now being prepared, so that with this description of the system in general attention .will be now turned more specifically to the safety device 53 shown in two parts in Figure 1 for greater clarity of illustration and in detail in Figures 2, 3 and 4.

The safety device comprises a main body portion, as the casting. 54, through which the gas pipe or fuelconduit l2 passes, as may be best seen in Figure 3. Valve means is provided within the device, comprising the valve member 55 movably mounted and having its valve head adapted to come into engagement with a valve seat 56 to close the conduit, Means for sealing the movable valve member to prevent loss of gas is here shown in the form of a bellows 51; and a spring 58, lying within the bellows, urgesthe valve member in a downward direction, tending to move it to closed position. Latch means, which will now be described, normally retains the valvememberln an open position so that there is uninterrupted flow of fuel to the burner: but as soon as the latch means is moved to released or un- 5 latched position the valve closes under the influence of the spring 58, thus cutting off fuel flow to the burner. In order to achieve the desired latching action a pivotally mounted pawl or dog 59 on the shank of the valve member, normally maintained in the position shown in Figure 3 by the spring 69, engages a shoulder or stop piece 6| mounted on a movable member 62. in engagement, as shown in Figure 3, the valve member is mounted in open position against the urging of the spring 58; but any movement'of the member 62 which moves the stop piece 6| out from under the pawl 59 unlatches the valve member\and permits it to move them to closed position. Since the pawl is of the spring-pressed pivotal type, the valve may be easily reset by pulling up on the finger ring 63 until the posi-- o casting 54.

The movable member 62 is mounted for both rockable'and bodily movement. Rockable movement is about the mounting pin 66 as an axis; and'bodily movement to the left (speaking with respect to Figures 2 and 3) is effected by slideable movement of the mounting bar 61 against the resistance of the spring 68. In addition to the spring 68 which resists bodily movement, springs 10 and 1| act through pins 12 and 13 on an extension 14 of the member 62 to provide resistance to rockable movement, although such movement is permitted when the resistance of either spring is exceeded.

The application of force tending to move the member 62 is through two pointed pins 15 and 116, these pins being attached to the movable head of bellows or Sylphons Tl and 18, respectively. Stationary heads 19 and so are fixedly mounted in the casting 54, these heads being provided with female portions 8| and 82 which receive male guide portions extending back from the movable Sylphon heads, as the guide portion 83. Fluid under pressure is admitted through the pipes 84 and 85 to the bellows, passing along a slot provided in the male guide members. It will be readily apparent that as long as the pressures in the two Sylphons are approximately equal and their combined pressure is less than 50 the resistance of the spring 68 the member 62 will remain in the position shown in the drawings, holding the valve member latched in open position. Should the pressure in one Sylphon rise without a corresponding rise in the other (or, to the same 'eil ect, if one pressure should drop without a corresponding drop in the other) the forces would no longer balance each other and the member 62 would rock to the right or left about the pin 66, either movement serving 70 to move the stop member 6| out from under the pawl 59, whereupon the valve member moves to closed position under the urging of the spring 58. That is, such rocking movement of the member 62 is effected as soon as the forces are unbal- 76 anced to an extent sufficient to overcome the When these two parts are,

opening in the giiide bracket 65 mounted on the resistance of one of the springs or II. Similarly, should bothpressures rise equally but to an undesirably high extent their combined force would exceed the resistancefof the spring 68 and the entire member 62 would move bodily to the left, again moving the stop member 6| out from under the pawl 59 and letting the valve member move to closed position. Minor differences in pressure, or fairly similar and simultaneous increases or decreases of pressure within reasonable ranges, do not effect movement of the member 62, so that the unlatching action takes place only upon abnormal conditions. I

Turning'now more particularly to Figure 1, it will be seen that the tube 84 connects to the liquid actuating leg lll leading from the fluid thermostat 29, so that the pressure in the Sylphon i 11 is the press'urein the thermostat 29, a function of still temperature. The other tube 85 is shown connected to the high pressure vapor side of the system, being connected to one end of the con- ,denser ii, the "pressure in the Sylphon "therefore being a function of highpressure refrigerant vapor in the condenser. If the refrigeration system is working properly the fluid thermostat pressure will rise slightly above still pressure and then drop slightly below it as transfers are effected; and as room temperatures or refrigera- I tion loads vary both pressures will rise together or fall together approximately similarly. The

" resistance of the spring 68 of the safety device is adjusted to be sufficiently high to resist the forces on the member 82 by the pressures in the still and thermostat bulb within safe operating ranges, as the full intended refrigeration capacity of the system at a 1i0-degree room temperature; and the resistance of the springs 10 and 'Il would be made sufficient to prevent rocking movement of the niember 82 in the normal fluctuations of the thermostat bulb pressure above and below still pressure.

Should any of the system conditions become abnormal and present possible danger, however, the safety device goes into operation to shut off the fuel supply. It will be apparent that if both pressures rose excessively, as upon a failure of condenser water flow, the member 62 would be moved bodily to the left to effect the desired unlatching action. Similarly, if the transfer mechanism failed to function and the concentration in the still kept boiling down, the excess of pres- We claim: 1

1. 'A safety device for controlling the fuel flow in an absorption refrigeration system, including: a flow control valve adapted to be latched open; movable ,means actuated by one condition or the system; a second movable means actuated by another condition of the system; and safety means operatively associated with both of said first mentioned means andadapted to be moved, when either of said conditions of the system becomes abnormal, to effect unlatching and closure of said valve.

2. A safety device for an absorption refrlger ation system, including: movable means actuated by one condition, of the system; a second of the system; means for balancing said means against each other; and safety means opera tively associated with the balancing means and adapted to be moved when either of said conditions of the system becomes abn rmal.

3. A safety device for controlling t e fuel flow in a continuous absorption refrigeration system having a still and other elements, including: a flow control valve adapted tobe latched open; movable means actuated by one condition of the system, said condition being still. pressure; movable means actuated by another condition of the system, said condition being still temperature; and safety means operatively associated with both of said first mentioned means and adapted to be moved, when either of said conditions of the system becomes abnormal, to efiect unlatching and closure of said valve.

4. A safety device for a continuous absorption refrigeration system having a still and other elements, including: movable means actuated by 'one condition of the system, said condition being still pressure; movable means actuated by another pressure condition of the system; means for balancing said means, against each other; and

safety means operatively associated with the balsure in the thermostat bulb over the still pressure 'in the unit 21 to open, rupture of any pipe on the high pressure side of the system, or any of a' number of other abnormal conditions presentingpossibility of danger would cause either an unbalancing or an excess of pressure in the safety device Sylphons, and result in operation of the safety device to shut down the system untilit can be given proper attention.

. While we have shown and described certain embodiments of our invention, it is to be underancing means and adapted to be moved when either of said conditions of the system becomes abnormal.

5. Apparatus of the character claimed in claim 4, wherein the other condition is the pressure in a fluid thermostat exposed to still temperature.

6. A safety device for an absorption refrigeration system, including: movable means actuated by one condition 'of the system; a second movable means actuated by another condition of the system; valve means including a seat and a movable valve member; spring means urging the valve member in one direction and latch means normally maintaining the valve member in a desired position against the urging of the spring, the latch means being operatively associated with both first mentioned movable means and adapted pressure; movable means actuated by another stood that it is capable of many modifications.

Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appendedclaims.

condition of the system; valve means including a seat and a movable valve member; spring means associated with both first mentioned movable means and adapted to be moved to unlatched position by an abnormal condition of the system.

wherein the valve means controls the supply of fuel to the burner.

9. A safety device for a continuous absorption refrigeration system having a still and other elements, including: movable means actuated by one condition of the system, said condition being still pressure; movable means actuated by another condition of the system; means for balancing said means against each other; valve means including a seat and a movable valve member; spring means urging the valve member in one direction; and latch means normally maintaining the valve member in a desired position against the urging of the spring, the latch means being operatively associated with the balancing means and adapted to be moved to unlatched position by an abnormal condition of the system.

10. A safety device of the character described including: a member mounted for rockable movement; pressure actuated means tending to rock said member in one direction; a second pressure actuated means tending to rock the member in the opposite direction; and an element operatively associated with the member and adapted to be moved as a result of movement of the member when either pressure actuating said means be-- comes abnormal.

11. A safety device of the character described including: a'member mounted for rockable and bodily movement; pressure actuated means tending to rock said member in one direction; a second pressure actuated means tending to rock the ment in one direction; and late -member in the opposite direction; a movable element; spring means urging the element in one direction; and latch means normally maintaining the element in a desired position against the urging of the spring, the latch means being operatively associated with said member and movable to unlatched position by any movement thereof.

.12. A safety device of the character described including: a member mounted for rockable and bodily movement; pressure actuated means tending to rock said member in one direction; a second pressure actuated means tending to rock th member in the opposite direction; increase in pressures actuating both said means tending to effectbodily movement of said member; spring means resisting movement of said member; a movable element; spring means urging the elem ans normally maintaining the element in a desired position against the urging of the spring, the latch means;

being carried by said member and movable to unlatched position by any movement thereof.

i 13. Apparatus of the character claimed in claim 12, wherein the movable element is a normally open valve member adapted to move into engagement with a seat when unlatched.

14. Apparatus of the character claimed in claim 9, wherein the valve means controls the supply of fuel to a burner adapted to heat the still, and the other condition of the system is still temperature.

RALPH E. SCHURTZ. JOSEPH N. ROTH,

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