US3487642A

US3487642A - Refrigerant condenser arrangement

Info

Publication number: US3487642A
Application number: US767871*A
Authority: US
Inventors: John P Norton
Original assignee: American Air Filter Co Inc
Current assignee: American Air Filter Co Inc
Priority date: 1967-01-24
Filing date: 1968-07-22
Publication date: 1970-01-06
Anticipated expiration: 1987-01-06

Description

Jan. 6, 1970 J, NORTON 3,487,642

REFRIGERANT CONDENSER ARRANGEMENT Original Filed Jan. 24, 1967 2 Sheets-Sheet 1' mvsmon. John 1? A/arzan Jan. 6, 1970 J. P. NORTON 3, 7,

REFRIGEHANT CONDENSER ARRANGEMENT Original Filed Jan. 24, 1967 2 Sheets-Sheet 2 54 453 I/ &

Fig. 2

INVENTOR- Jobn E lib/t0? United States Patent ABSTRACT OF THE DISCLOSURE The present invention relates to fluid condenser systems andmore particularly relates to condenser arrangements including at least two different fluid paths and cooperative valve means for simultaneously controlling the flow conditions in a stream of pressurized vaporizable-condensible working fluid passed through condenser means and regulating the effective condensing area in response to change in condition of the fluid emitted from the condenser.

CROSS-REFERENCE TO RELATED APPLICATIONS The present invention relates, in part, to co-pending application S.N. 516,641 filed Feb. 18, 1966 by Harold L. Kirk and John P. Norton, now US. Patent 3,365,133, and the present application is a division of application Ser. No. 611,300, filed J an. 24, 1967 and which is now Patent No. 3,430,453.

BACKGROUND OF THE INVENTION In refrigeration systems of the type where a vaporizable-condensible refrigerant is circulated through a fluid flow circuit including cooperatively connected compressor, condenser, expansion device, and evaporator, the pressure, temperature, and flow rate of refrigerant through the circuit are interrelated and affect system performance. This is because the refrigerant pressure at the compressor outlet significantly influences the pressure at the inlet of the refrigerant expansion device so, for example, a decrease in pressure decreases the rate of flow of refrigerant through the expansion device to substantially reduce the refrigerating capacity of the system. Furthermore, in such previous refrigeration systems the pressure of the refrigerant emitted from the condenser has been related to the temperature of the cooling medium supplied to the condenser so an uncontrolled decrease in temperature of the cooling medium supplied to the condenser results in reduced pressure in the refrigerant emitted from the condenser, and vice versa, regardless of the cooling demands on the system.

Previous refrigeration systems have provided various complicated, expensive arrangements to maintain optimum compressor discharge pressure. One such previous arrangement has included means to control the pressure of the refrigerant emitted from the compressor in response to change in the temperature of the cooling medium supplied to refrigerant condenser while other arrangements have directly controlled compressor discharge pressure regardless of refrigerant pressure at the expansion device.

In other methods, heat is added to the refrigerant to selectively increase the temperature, and pressure, of the refrigerant at the compressor outlet or the temperature or flow rate of the cooling medium supplied to the refrigerant condensing means, for example ambient air, is regulated to control the temperature of the refrigerant within the condenser.

In some cases, means have provided to flood selected 3,487,642 Patented Jan. 6, 1970 ice portions of the condenser with refrigerant in accordance with the pressure at the outlet of the compressor to reduce the effective heat transfer area of the condenser and correspondingly decrease the heat loss by the refrigerant to increase refrigerant pressure. Such arrangements provide sluggish control and response to change in conditions is slow because the condenser must be drained or filled in accordance with changes in refrigerant pressure and the time required for draining or filling the condenser is significant.

Another method previously used to control the outlet pressure from the refrigeration compressor has included dividing the refrigerant flow emitted from the compressor between at least two separate condensers in accordance with the pressure at the outlet of the compressor. Such arrangements require cooperative valve and control means at the compressor outlet to control the quantity of compressed refrigerant flowing to the selected condensers. Such refrigerant flow control is not directly and rapidly responsive to change in condenser pressure or temperature at the condenser outlet nor do such systems provide means to control the quality or flow rate of refrigerant supplied to the expansion device.

SUMMARY OF THE INVENTION It has been recognized that the present invention provides a straightforward, inexpensive condenser and condenser control arrangement for use in a closed fluid circuit to efficiently control the condition of vaporizablecondensible working fluid emitted from a condenser in response to changes in the condition of the working fluid at the condenser outlet. Moreover, the present invention provides a straightforward refrigerant control arrangement with a minimum number of moving parts to simultaneously sense the condition of the refrigerant at the condenser outlet and control the refrigerant flow rate and effective condensing area without complicated interrelated valve and control apparatus.

Furthermore, it has been recognized that the present invention provides a valve arrangement which not only improves the operability of the system and uniformly controls the quality of the refrigerant supplied to the expansion device but also simultaneously maintains the refrigerant pressure at the compressor outlet pressure within selected limits.

It has been further recognized that the present invention provides a condenser arrangement which can be applied in fluid flow circuits of the general type where a vaporizable-condensible Working fluid is condensed and it is desirable to control the pressure within a selected portion of the circuit, the rate of condensation of working fluid and/or the condition of the working fluid at the outlet of the condenser. For example, an advantageous condenser arrangement in accordance with the present invention can be used to control the condition of working fluid emitted from a condenser in an air heating apparatus Where heated vaporizable-condensible working fluid is circulated through a fluid flow circuit and is provided to a condenser to heat a stream of air.

Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth hereinafter.

More particularly, in a heat exchange fluid flow circuit Where a vaporizable-condensible working fluid is circulated through a circuit including means to alternately vaporize and condense the fluid, the present invention provides an improved condenser arrangement comprising: condenser means having at least two separate flow conduits to conduct working fluid through the condenser, each conduit having an inlet to communicate with means to vaporize said working fluid, and a working fluid outlet;

valve means including an elongated casing having a working fluid outlet and working fluid inlet ports communicatively connected to outlets of selected flow conduits of said condenser; piston means to move longitudinally through the casing to close selected working fluid inlet ports; and, means to move the piston in the casing to control such selected working fluid inlets in response to condition of working fluid admitted to the casing from the condensing means.

It will be appreciated by those skilled in the art that various changes can be made in the arrangement, construction or form of the condenser arrangement disclosed herein without departing from the scope or spirit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS condenser arrangement in accordance with the present invention; and

FIGURE 4 is a view, in section, showing an example of a temperature-responsive valve arrangement which can be used in a condenser arrangement in accordance with the present invention.

DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION FIGURE 1 shows a condenser 2 and valve 3, in accordance with the present invention, provided in an example of a flow circuit including a compressor 1, refrigeration expansion valve 4 and an evaporator located in a space to be conditioned. In operation of the refrigeration system as shown in FIGURE 1 refrigerant is pumped from the outlet of compressor 1 to manifold 8 and the com-.

pressed refrigerant flows through the selectively open conduits of condenser 2 so at least a part of the refrigerant is condensed and the condensed refrigerant is supplied to an expansion device 4. In accordance with one feature of the present invention an arrangement is provided to simultaneously regulate the refrigerant flow rate and condensing area so the pressure of the refrigerant supplied to expansion valve 4 is relatively constant and the cooling capacity of the refrigeration system is relatively unaffected by conditions prevailing in the cooling medium supplied to the condenser.

Condenser 2 includes an inlet manifold 8 to receive compressed refrigerant from the outlet of the compressor by means of a conduit 7. In accordance with one feature of the present invention, condenser 2 includes at least two separate flow conduits, and in the example of FIGURE 1 four

separate flow conduits

9, 11, 12, and 13 are provided. Each conduit has an inlet communicating with manifold 8 and a separate outlet connected to valve 3 as hereinafter described.

A conduit 15 is provided to connect outlet 14 of valve 3 with an expansion device 4 to provide expanded cooled refrigerant to an evaporator coil 5 located in space 6 to be served by the refrigeration system. Refrigerant is returned from evaporator 5 to the inlet of compressor 1 by means of a refrigerant return conduit 17.

FIGURE 3 is a view, in section, of one example of a valve 3 which can be used in a condenser arrangement in accordance with the present invention and includes an elongate outer casing 10 having refrigerant inlet ports 9a, 11a, 12a, and 13a, in longitudinally spaced relation in the side of the casing. In accordance with one feature of the present invention, each of the inlet ports 9a, 11a, 12a and 13a is connected to the outlet of a separate conduit of condenser 2, for

example conduits

9, 11, 12, and 13 respectively.

A piston 21 is cooperatively adapted to move in longitudinal sliding relation within casing 10 to advantageously control the opening and closing of a number of the inlet ports and divide casing 10 into

chambers

27 and 28 on either side of the piston in accordance with the position of the piston in casing 10. Chamber 28 can be provided to receive piston 21 under selected conditions so none of the inlet ports are covered and closed and in response to a selected change in condition of refrigerant piston 21 can move freely out of chamber 28 to cover selected inlet ports. In the example of FIGURE 3, piston 21 can advantageously be long enough to cover only inlet ports 9a, 11a, 12a and a stop 20 can be disposed, as shown, in casing 10 to restrict the movement of piston 21 so inlet 13a is never closed and a minimum refrigerant fiow is assured.

Piston 21 can be of straightforward construction using a cylindrical section of selected length dependent on the spacing between inlet ports 9a, 11a, 12a, 13a, and the number of such ports to be open or closed at any one time. In the example of FIGURE 3, piston 21 includes machined or rolled circumferential grooves (not shown) for receiving O-rings 22 of suitable materials, for example Teflon, to restrict leakage of compressed refrigerant past piston 21.

Piston 21 advantageously moves freely in casing 10 as hereinbefore described to close or open selected compressed refrigerant ports in accordance with the disposition of the inlet ports and the position of piston 21 in casing 10. Means, for example a spring 23, can be provided to maintain selected force on one end of piston 21. In the example as shown in FIGURE 3, spring 23 can be a compression spring where the force exerted by the spring varies with the extent of compression of the spring to provide a variable force on one side of piston 21 and advantageously urge piston 21 through housing 10 toward refrigerant outlet 14 of casing 10.

A gas bleed outlet 16 can be provided from chamber 28 for the escape of the compressed refrigerant which leaks past piston 21. A pressure responsive relief valve 16a can be provided at outlet 16 to control the rate at which refrigerant escapes from chamber 28 to provide a relatively constant back pressure within chamber 28 so movement of piston 21 through casing 10 is unaffected by the rate at which refrigerant leaks past piston 21.

When a pressure responsive valve as shown in FIG- URE 3 is used in a refrigerant circuit as shown in FIG- URE 1, refrigerant entering chamber 27 exerts a force on the other end of piston 21 to urge the piston in a direction to compress spring 23 and open inlet ports where the force exerted by the spring increases with increased refrigerant pressure so the piston assumes balanced position in casing 10 dependent on the pressure of the refrigerant entering chamber 27. Selection of a mechanical spring means 23 with known loading characteristics provides an arrangement where the piston will move to a prescribed position in casing 10 in response to selected refrigerant pressure in chamber 27 and will respond predictably to change in pressure of the refrigerant to open or close refrigerant inlets 9a, 11a, and 12a. For example, as the pressure of the compressed refrigerant emitted from condenser 2 is decreased, the force exerted on the end of piston 21 by the fluid entering chamber 27 is diminished, so the piston 21 moves in casing 10 in response to the force of spring 23 to cover additional refrigerant inlet ports and shut off the flow of refrigerant through the corresponding conduits of condenser 2. On the contrary, when the pressure in condenser 2 is increased, piston 21 is urged in an opposite direction to open additional conduits through condenser 2 to increase the flow of refrigerant. It will be noted that as additional conduits are opened in response to increased refrigerant pressure, the pressure drop through the condenser is decreased and the condensing area of condenser 2 is simultaneously increased to provide additional heat transfer area so the refrigerant is cooled to decrease the refrigerant pressure at the outlet of condenser 2 and compressor 1.

FIGURE 4 is a view, in section, showing another eX- ample of a valve which can be used in a condenser arrangement provided by the present invention. The valve as shown in FIGURE 4 is responsive to the temperature of the refrigerant admitted to chamber 37 from condenser 2 of the refrigeration system of FIGURE 1 and is in some respects similar to the pressure responsive valve as shown in FIGURE 3 in that it includes an elongate outer casing a having longitudinally spaced inlet ports 9b, 11b, 12b, and 13b where each inlet port communicates with

conduits

11, 12, and 13 respectively, of condenser 2. A piston 31 is adapted to move through casing 10a to close or open selected number of inlet ports and divide casing 10 into

chambers

37 and 38 where chamber 38 is adapted to receive piston 31 under selected conditions so that none of the inlet ports are closed.

Piston 31 can be of selected length to block a selected number of inlet ports and, as in the example of the vlave of FIGURE 3, piston 31 is long enough to cover ports 9b, 11b, and 1217. Also, as in the example of the valve of FIGURE 3, a stop 36 can be provided in casing 10 to prevent piston 31 from blocking all of the inlet ports to completely stop the flow of refrigeration through condenser 2.

Piston 31 is similar to piston 21 of FIGURE 3 and can be of straightforward construction using a cylindrical section with grooves machined or rolled for receiving O-rings 32 of a suitable material, for example Teflon. O-rings 32 are provided to restrict flow of refrigerant past piston 31, but a small amount of leakage is likely to occur so bleed port 16 can be provided and is connected to the inlet of compressor 1 by means of conduit 18. It is desirable to provide gas bleed means such as outlet 16 and conduit 18 even if no refrigerant leaks past piston 31 because movement of piston 31 causes related expansion and contraction of

chambers

37 and 38 and the gas flow resulting from change in chamber must be accommodated without affecting the movement of the piston. Since a small amount of refrigerant leakage can be accommodated and O-ring seals can be used, the relative machine tolerance for piston 31 and valve casing 10 are not restrictive and the piston can be adapted to move freely through casing 10.

In the example of a valve 3 as shown in FIGURE 4, piston 31 can be moved in casing 10 by a temperature responsive actuator 34, for example a temperature responsive actuator manufactured under the trade name Elac by Standard-Thompson Company, where a change in the temperature of refrigerant entering the valve causes a change in linear dimension of the actuator to move the piston. Actuator 34 is supported in casing 10 by mounting block 37 and piston 31 can be fastened to actuator 34, or, as shown in the example of FIGURE 3, piston 31 can merely rest on actuator 34. The Elac temperature responsive actuator of the example of FIGURE 4 includes a piston 34a which is forced from housing 34b in response to an increase in temperature. The housing can include a substance having a high coeflicient of thermal expansion to obtain a significant movement of piston 34a with relatively little change in temperature. Some temperature responsive actuators, for example the actuator where piston 34b is filled with material having high coefficient of thermal expansion, do not provide means to re turn the piston to the housing in response to decreased temperature, so a spring 33 can be provided to supply the return force necessary to simultaneously reposition both piston 34a in housing 34 and piston 31 in casing 10. As distinguished from spring 23 of the embodiment of FIGURE 3 which advantageously causes movement of piston 21 spring 33 prevents any movement of piston 31 in casing 10a in response to change in refrigerant pressure in chamber 37. In a valve as shown in the example of FIGURE 4 where the piston movement is controlled by thermal element 34 and restricted by a spring 33 it is not necessary to provide absolute control of the gas pressure in chamber 38' on the inactive side of the piston because the actuator is responsive to temperature and provides a significant operating force to overcome a slight imbalance in gas pressure across the piston. However, as discussed previously, means, for example a bleed 16, can be provided to prevent the build-up of significant gas pressure or vacuum in chamber 38 which, if uncontrolled, could develop suflicient force to adversely affect the responsiveness of the piston 31 to change in temperature of refrigerant entering casing 10a.

In the refrigeration system as shown in FIGURE 1, which can include a valve as shown in the example of FIGURE 4, the flow of refrigerant through condenser 2 is controlled by temperature of the refrigerant emitted from condenser 2. It will be noted that the temperature of the refrigerant emitted from condenser 2 decreases with a decrease in temperature of cooling medium for example air, supplied to condenser 2 or with a decrease in the temperature of refrigerant emitted from compressor 1. A decrease in refrigerant temperature is sensed by thermal responsive element 34 of valve 3 and the element permits withdrawal of piston 31 in casing to close additional inlet ports in casing 10a. The flow of refrigerant through condenser 2 is thereby restricted so the outlet pressure of compressor 1 is increased and the effective condensing area of condenser 2 is decreased so the temperature and the pressure of the refrigerant emitted from condenser 2 are increased. On the other hand as the refrigerant temperature is increased, temperature responsive element 34 expands and piston 31 is moved in an opposite direction in casing 10a to open additional flow conduits of condenser 2 to increase the flow of refrigerant from compressor 1 and decrease the pressure and temperature of the refrigerant.

As stated hereinbefore, the arrangement in accordance with the present invention can be used in any application where a working fluid is vaporized and condensed in a fluid flow circuit. FIGURE 2 is a schematic diagram of an air heating device including a condenser arrangement in accordance with the present invention. The heater illustrated in FIGURE 2 includes a vaporized working fluid generator 41 having an integral heat source and a boiler to provide vaporized working fluid at selected pressure. The air heating device can further include a fluid responsive engine 42 driven by pressurized working fluid emitted from generator 41 as hereinafter described. In accordance with the present invention, condenser 40 receives heated working fluid and transfers the heat to the air passed through condenser 40 in heat exchange relation.

The heater as shown in the example of FIGURE 2 is self-powered so an auxiliary source of power, other than vaporized fluid generator 41, is not necessary. The selfpowered air heater as shown in FIGURE 2 incudes a power transmitting device 43 which receives power from engine 42 to drive several auxiliary elements including a combustion air blower 44, fan device 47, a motive fluid feed pump 53, and a fuel pump 48. Each of the elements can be diivingly connected to power transmitting means 43, for example by drive shaft 44a, 47a, 48a, and 53a respectively.

Combustion air blower 44 is provided to supply combustion air to the heat source included in vapor generator 41 and fan 47 is provided to move the stream of air to be heated through condenser 40. Pump 53 is provided to return condensed fluid from receiver 54 to vapor generator 41 and fuel to be burned in working fluid generator 41 can be provided by means of a pump 48 where the fuel is delivered to inlet 52 from a storage source (not shown). It is to be noted that a fuel control valve 49 can be provided to control fuel flow to vapor generator 41 in response to selected conditions, for example, the temperature of the air emitted from condenser 40 as measured by thermal element 51 and a condenser arrangement provided by the present invention can be used to control working fluid pressure and temperature. It will be noted that the rate of feed of fuel to working fluid generator 51 determines the rate of vaporization of fluid at selected pressure, and the quantity of heat available to heat fluid passing through condenser 40.

As previously discussed, engine 42 receives vaporized motive fluid from generator 41 to transform a portion of the pressure energy of the working fluid to rotary motion to drive power transmitting means 43. Reduced pressure motive fluid is exhausted from engine 42 to condenser 40. A portion of the vaporized motive fluid from generator 41 can be by-passed around engine 42 through by-pass 45 to maintain a constant differential pressure across engine 42 to selectively control power output from engine 42 where by-pass 45 includes pressure responsive valve 46 to control the differential pressure across turbine 42 and the pressure at the outlet of generator 41. The fluid which is by-passed around engine 42 and the fluid passed through engine 42 are recombined to flow to condenser 40 to impart heat to air passed through condenser 40 in heat exchange relation. Flow of motive fluid from condenser 40 is controlled by valve 3 and the fluid is returned to receiver 54 to be recycled to generator 41.

As explained hereinbefore with reference to the example of FIGURE 1, condenser 40 of the heater of FIG- URE 2 can include a number of separate flow conduits, for example 90, 11c, 12c, and 130 Where each separate conduit can be connected to valve 3 through separate inlet ports. If a pressure responsive valve as illustrated in FIGURE 3 is used, an increase in pressure of the fluid in chamber 27 of casing indicates increased fluid pressure in condenser 40 which can, for example, be the result of reduced rate of condensation of working fluid. The reduced rate of condensation of working fluid can result from several factors including an increase in the temperature of the air supplied to the condenser to be heated without a corresponding change in the rate of feed of fuel to generator 41 as hereinbefore described. The present invention advantageously provides an arrangement to maintain working fluid pressure in such air heating devices to promote stable operations while fuel feed rate corrections are made. In response to an increase in working fluid pressure, piston 21 of valve 3 moves to open additional conduits through condenser 40 to increase effective heat transfer area and the rate of condensation of fluid in condenser 40. Likewise, decreased fluid pressure resulting from increased rate of condensation, which can result from decreased temperature of the air passing over condenser 40, causes valve 3 to close to decrease heat transfer area and increase working fluid pressure. In the application as illustrated in FIGURE 2 valve 3 can be either pressure or temperature responsive and can advantageously be adjusted to maintain selected refrigerant conditions, for example, complete condensation of motive fluid in condenser 40, or a constant downstream pressure at the outlet of condenser 40.

The invention claimed is:

1. In a closed circuit through which a vaporizable-condensible working fluid is circulated to provide a useful heating effect, the circuit including pump means to pump working fluid through the circuit, heat vaporizer means to vaporize the Working fluid, fluid responsive engine means to receive vaporized fluid to convert a portion of the energy of such vaporized working fluid to useful power and a condenser means to condense a portion of said vaporized working fluid, the present invention provides an improved condenser means including: condenser means having at least two separate flow conduits to conduct working fluid through said condenser, each conduit having an inlet to communicate with said source of vaporized working fluid, and a working fluid outlet; valve means including an elongate casing having a Working fluid outlet and working fluid inlet ports, each inlet port being communicatively connected to outlets of selected flow conduits of said condenser means; piston means to move longitudinally through said casing to open and close selected working fluid inlet ports; and define first chamber means between one end of said casing and said piston and second chamber means between the other end of said casing and said piston so said second chamber is in communicative relation with said working fluid inlet from said casing and said fluid outlet ports; and means to move said piston to said casing to close off selected working fluid inlet ports in response to change in temperature of the working fluid admitted to the casing from said condensing means.

References Cited UNITED STATES PATENTS I 6/1915 Gibson -95 CARROLL B. DORITY, JR., Primary Examiner US. Cl. X.R. l40, 101