US2021689A - Check valve for refrigerating systems - Google Patents

Description

Nov. 19, 1935.

- Filed March 20, 1935 Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE 'mesne assignments, to General Household Utilities Company, Chicago, III., a corporation or Delaware Application March 20, 1933, Serial No. 661,661

4 Claims. (01. 62-115) The present invention relates to refrigerating systems and more particularly to check valves used therein and therewith. V

In usual refrigeration, there is essentially an evaporation of a fluid refrigerant for the absorption of heat. The refrigerant is usually a volatile liquid contained in an evaporator, and evaporation or ebullition is effected by mechanical exhaustion or chemical absorption. The former is known as the pressure type of refrigeration and the latter as the absorption type. The present invention relates to the pressure type. In such a type, is included means for convert-- ing the vapors into liquid state for re-use in the 5 evaporator. The converting means comprises a pump frequently referred to as a compressor, and a cooling means often termed a condenser.

The present invention comprehends the use of dichloromethane or similar substance having 20 the same or substantially the same physical characteristics and properties. It has the chemical formula CHzClz. It is non-inflammable, nonexplosive, non-corrosive (with or without moisture) of most metals used in refrigerating devices,

5 non-poisonous, and readily extinguishes fire, in-

both its liquid and gaseous or vaporous forms. At atmospheric pressure, it has a boiling point of about 105 F. and is therefore a liquid at all normal temperatures. Its density is about 1.33. Be-

ing a liquid, it is easily handled and can be simply poured at any point desired into the refrigerating system to charge it. It does not give ofiobjectionable fumes. Its vapor has a very slight and inofiensive odor. The vapor has a higher 5 specific gravity (about 3.0) than air, and sinks in air.

The refrigerant used in the present invention, is used at low pressure. This is very advantageous because it avoids any rupture in the system, and.

40 reduces leakage to a minimum. At an absolute pressure of 3.2 Hg, its boiling point is 14 F. The pressure differential of the pump in the present system, is about or less than one atmosphere, and the head pressure at the pumps outlet is 45 about atmospheric. This refrigerant has a greater thermal efficiency than any other known practical refrigerant. Its co-efficient of per formance is 5.14 and is only 0.16 below the theoretical maximum. It requires less horse power 50 per ton of refrigeration produced than any other known refrigerant. The term ton of refrigeration means the amount of refrigeration effected when melting a ton of ice. Its factor is 0.918 as against the theoretical factor of 0.821. It is 55 miscible with oil and hence no stratum of oil can be formed on the refrigerant in the evaporator to strangle or choke the evaporation of the liquid refrigerant.

It is an object of the invention to provide a novel check valve means or the like in the circuit 5 between the evaporator and the exhausting or pumping means, which will be sensitively active to small changes or small differentials of pressure of the vapor moving therein.

Another object is to provide a novel valve 10 means located as close as possible to the pumping means and which may discharge directly into the pumping means so as to decrease the volume of space between the valve and the pump, and to limit to a minimum the oil and gas or vapor that 15 might tend to back-up from the pump.

A further object is to provide a novel valve means with the inlet and outlet thereof so arranged as to reduce to a minimum the head therebetween and to also decrease the drop of pressure between the pump and evaporating means for increasing the efficiency of the system.

The invention also comprehends as a novel feature thereof, the provision, in .a check valve of the kind disclosed, of a thin light-weight smooth surfaced and stiff wafer-like or disc-like valve memher which will act quickly and sensitively to small changes orsmall differentials of pressure in a sub-atmospheric range of pressures.

Other objects; advantages, capabilities and features are comprehended by the invention as will later appear and as are inherently possessed by the invention.

Referring to the drawing:

Fig. 1 is a schematic view of a refrigerating systern embodying the invention; v

Fig. 2 is a longitudinal sectional view taken through the novel check valve means of this invention; v

Fig". 3 is a horizontal sectional view taken in a 4() plane represented by line 33 in Fig. 2;

Fig. 4 is a transverse sectional view taken in a plane represented by line 4-4 in Fig. 2; and

Fig. 5 is a plan view of the valve sealing member.

Referring more in detail to the drawing, the embodiment selected to illustrate the invention is shown in connection with a refrigerating system or circuit comprising an evaporator I, a vapor duct 2, a flexible or compliant duct section 3, a duct part 4, check valve means 5, pump 1i, duct part 1, cooling means or condenser 8, duct 9,- receivirig and trap chamber l0, trap valve II, and return duct l2 connected to the evaporator. This forms a closed circuit in which is contained a given quantity of the refrigerant. The refrigerant used is preferably dichloromethane or one having the same or substantially the same physical characteristics and properties.

The evaporator I comprises a drum I3 to the lower part of which are connected a group of tubes |4 extending around and embracing the freezing zone box l5 in which may be suitably supported shelves l6 and I! for holding ice trays and the like. At the side of the box 5 ,is an entry or distributing chamber 8 which is connected at one end to the duct |2 for receiving liquid refrigerant therefrom. The chamber I8 is connected to all the tubes l4 and is designed to supply and distribute the liquid refrigerant to the tube parts IQ of all the tubes in substantially equal amounts, and also to induce an upward movement of the refrigerant in the tube parts l9 and hence to induce a circulation in the circuit of the tubes l4 and the drum l3.

The walls of the duct part 3 are folded or convoluted so that this part is flexible and yieldable so as to absorb and arrest transmission of any vibration that might be set up or produced by the pump and other moving parts, thus preventing vibration of the duct 2 and the evaporator I and so forth.

The pump 6 is preferably of the rotary piston type and has an inlet 20 preferably formed integral with the pump housing and discharging directly in the exhaust part of the pump. The pump is preferably enclosed in a dome 2| into the upper part of which the pump discharges the compressed gases or vapors, and from this dome 2| leads the outlet pipe or duct 7 which is directly connected to the condenser 8.

The pump 6, that is, the rotary piston thereof, is operated by a suitable motor 22 by way of the pump shaft 23 finding its bearings in the pump casing. On the end of the shaft is a fan 24 operative to cause movement of cooling air through the condenser 8.

The condenser 8 may comprise a serpentine coil 25 carrying a plurality of cooling fins 26. The showing in Fig. l is merely conventional for the sake of clearness, but in the actual structure the condenser is disposed in a plane parallel to the plane of rotation of the fan 24.

From the condenser the compressed and liquefied refrigerant flows by way of the tube or duct 9 to and into the chamber ll! within which is a float device (not shown) adapted to operate the valve H for controlling the flow of the liquid refrigerant through the duct l2 and to the evaporator I.

The check valve 5 comprises a casing 21 enclosing a chamber 28 communicating with an outlet passage 29 provided in the outlet fitting 30 secured to the inlet fitting 3| forming an integral part of the pump housing, the fittings 30 and 3| being secured together by bolts 32 as clearly shown in Figs. 3 and 4, with a suitable gasket or the like 33 therebetween.

Below the chamber 28 is a valve port 34 sur rounded by a valve seat member 35 having a smooth flat valve seat 36. The port 34 communicates with a passage part 3'! leading to an inlet passage 38 provided in the inlet part 39 of the valve casing. The inlet part 39 is threaded for connection to a fitting 40 connected to the duct 4.

On the seat normally seats a thin stiff fiat lightweight wafer-like or disc-like valve element or member 4|. The valve member may be of metal such as aluminum, or some non-metallic material, such as bakelite, or the like. It has a smooth upper part of the casing 21.

or polished surface so as to form a close hermetic seal with the seat 36.

Above the valve member 4| is located a limit stop in the form of a cross 42 fixed or rigid with a post 43 forming an integral part of a cap 44 suitably secured in an opening 45 provided in the This opening affords access to the interior of the valve device.

As above indicated, one of the objects of the present invention, is to provide a novel device so designed as to reduce to a minimum the drop of pressure between the pump and the evaporating means for increasing the efficiency of the system. As for example, if, in a system using an ordinary type of check valve and connection thereto, we assume a room temperature of about F., the differential pressure between the high and low sides of the system may be as much as ten (10) lbs. (from 4.7 lbs. absolute to atmospheric pressure). If the drop in pressure in the circuit between the evaporating means to the pump be, say 1 lb. per square inch, due to the friction of the gas flowing through the suction line, the bends in the fittings and the check valve, and the weight of the valve element in the check valve, it will become apparent that such drop in pressure may amount to as much as 10% of the differential pressure.

If, also we assume that there is no such drop in pressure, then in a. system such as I have disclosed and which uses dichloromethane or the like, and with a 0 F. temperature in the evaporator, the pressure in the evaporator will be 0.995 lbs. per square inch. Now, with a drop in pressure of 1 lb. as above indicated, the pressure in the evaporator would be 1.995 lbs. which would correspond to a temperature of 20 F.

Therefore, it is an object of the present invention to reduce this drop in pressure by making the suction line 2--34 as direct and short as possible and the valve member 4| in the check valve, as light in weight and as sensitive in action as may be. By making the valve member 4| of much less weight than has ever been done before,

the drop in pressure due to the energy required I to move the valve is greatly reduced and hence the efliciency of the system is accordingly increased.

Another feature present in this invention, is

that the valve member 4| and the parts of the check valve 5 are so designed that adequate flow of the gas or vapors is obtained when the valve is tipped up or tilted from its seat about a point on its edge as a fulcrum. In this way only one half of the energy is used than would be required if the valve member were to be lifted bodily to contact with the cross 42. is determined by the position of sage 29.

This mode of action by the valve also avoids the creation of eddy currents in the gas or vapor, again reducing the loss or drop in pressure.

A further feature is also present in this invention. In normal operation of the system, some the outlet pasoil is carried over from the pump to the evaporator Which side will tilt up drop in pressure. If, for instance, the duct 4 continued downward in the form of a U-bend and then upward into the bottom of the checkvalve 5, the oil head would be so great as to greatly reduce the efficiency of the system. The present invention avoids such disadvantage.

While I have herein described and upon the drawing shown an illustrative embodiment of the invention, it is to be understood that the latter is not limited thereto but comprehends other constructions, details, arrangements of parts, features and the like, Without departing from the spirit of the invention.

Having thus disclosed the invention, I claim:

1. In a refrigerating system comprising a circuit containing a quantity of a fluid refrigerant, an evaporating means wherein the refrigerant is converted from liquid to gaseous or vaporous states with the absorption of heat and at a subatmospheric pressure, and a rotary pump for drawing the refrigerant in gaseous or vaporous state from said evaporating means, a check valve connected proximately to said pump and having an outlet discharging directly into said pump and having an inlet connected to a duct extending to said evaporating means, said valve and pump being substantially on the same level, and a light weight stiff valve member normally disposed substantially horizontally in said check valve and rapidly movable to and from closing position upon small differentials of pressure of the attenuated vapor drawn from said evaporating means and through said check valve. I

2. In a refrigerating system comprising a circuit containing a quantity of a fluid refrigerant, an evaporating means wherein the refrigerant is converted from liquid to gaseous or vaporous states with the absorption of heat and at a subatmospheric pressure, and a rotary pump for drawing the refrigerant in gaseous or vaporous state from said evaporating means, said valve and pump being substantially on the same level, a check valve connected proximately to said pump and having an outlet discharging directly into said pump and having an inlet connected to a duct extending to said evaporating means, and a light weight stiff valve member normally disposed substantially horizontally in said check valve and rapidly movable to and from closing position upon small differentials of pressure of the attenuated vapor drawn from said evaporating means and through said check valve, and means for limiting the movement of said Valve member to open position thereof.

3. In a refrigerating system comprising a circuit containing a quantity of fluid refrigerant, an evaporating means wherein the refrigerant is converted from liquid to gaseous or vaporous states with the absorption of heat and at a subatmospheric pressure, and a rotary pump for drawing the refrigerant in gaseous or vaporous state from said evaporating means, a check valve connected proximately to said pump and having an outlet discharging directly into said pump and having an inlet connected to a duct extending to said evaporating means, said valve and pump being substantially on the same level, and a light weight stiff valve member normally disposed substantially horizontally in said check valve and rapidly movable bodily to and from closing position upon small differentials of pressure of the attenuated vapor drawn from said evaporating means and through said check valve, and means for limiting the movement of said valve member to open position thereof, said outlet and said inlet being arranged near to each other in a vertical direction and so spaced as to permit free bodily movement of said valve member therebetween.

4. In a refrigerating system comprising a circuit containing and operating with a refrigerant having the physical characteristics of dichloromethane and for acting on the attenuated vapors of said refrigerant at sub-atmospheric pressures, an evaporating means wherein the refrigerant is converted from liquid to gaseous or vaporous pheric pressures.

JAMES D. JORDAN.

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