KR200412565Y1 - Refrigeration expansion valve with thermal mass power element - Google Patents

Abstract

The thermostatic expansion valve for a vehicle air conditioning system includes a housing and a power element supported by the housing. The power element includes a diaphragm and a pressure pad disposed against the diaphragm. The pressure pad can be formed in one piece from copper, copper alloy or other material, which material is at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably at least about 170 W / mK (1200 BTU-in / hr-ft ^2- ° F), more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ^2- ° F) thermal conductivity and at least about 8 g / cm ³ ( Fusion, composite, mixture, or other combination having a density of 0.3 lb / in ³ ), and the pressure pad is connected through the stem to a valve element in the housing to control the refrigerant flow between the condenser and the evaporator. The use of this material in the pressure pad reduces the valve's sensitivity to external temperature changes and reduces the valve's hunting.

Expansion valve, condenser, evaporator, compressor, power element, pressure pad

Description

REFRIGERATION EXPANSION VALVE WITH THERMAL MASS POWER ELEMENT}

The present invention relates generally to temperature controlled expansion valves for air conditioning systems, and more particularly to temperature controlled expansion valves for vehicle air conditioning systems.

In a typical vehicle air conditioning system, the refrigerant is compressed by a compressor unit driven by the vehicle engine. The refrigerant compressed at high temperature and high pressure flows into the condenser where heat is removed from the compressed refrigerant. The refrigerant then moves through the receiver / dryer to the expansion valve. As the refrigerant flows through the valve orifice, the expansion valve throttles the refrigerant, which causes the refrigerant to phase change from liquid to saturated liquid / gas mixture as it enters the evaporator. In the evaporator, the heat absorbed from the surroundings is replaced by the latent heat of vaporization of the refrigerant, thereby cooling the surrounding air. The low pressure refrigerant from the evaporator flows back to the suction side of the compressor to restart the cycle.

In order to maximize the performance of the air conditioning system, the high pressure refrigerant flowing through the expansion valve must be adjusted in response to the degree of superheat of the refrigerant flowing between the evaporator and the suction side of the compressor. Superheat is defined as the temperature difference between the actual temperature of the low pressure refrigerant flow and the evaporation temperature of the flow. One type of device used to remotely detect the degree of overheating of the flow is a filler bulb. The filler bulb is arranged in contact with the pipe carrying the low pressure refrigerant. A pressure carrier extends from the filler bulb to the valve element in the expansion valve to regulate the refrigerant flow between the evaporator and the condenser.

Also, a more recent device for detecting the degree of flow overheating is a block-type (bulbless) thermostatic expansion valve. A bulbless temperature controlled expansion valve typically includes a power element that includes a diaphragm mounted between the domed head and the support cup on the valve body. A "charge" is located in the head chamber defined by the domed head and one (top) surface of the diaphragm. The support cup and the other (lower) surface of the diaphragm together with the body of the expansion valve define a diaphragm chamber. The pressure pad is located against the lower surface of the diaphragm and extends downwardly from the evaporator outlet into the refrigerant passage through the diaphragm chamber and the opening in the valve body. The valve stem is connected to the pressure pad and passes through the bore in the valve body towards the valve element that regulates the valve orifice between the first port (to the condenser) and the second port (to the evaporator) in the valve body. Extend further downward.

A valve element for a typical thermostatic expansion valve includes a ball located in a ball retainer or ball seat that is biased by a spring against a valve orifice between the condenser port and the evaporator port. It is also known to support the ball directly against the coil end of the spring and to use a conical element instead of the ball. In any case, the valve stem engages the ball and presses the ball away from the valve orifice in response to the movement of the diaphragm. The spring is held in place by a gland or spring seat that can be screwed into a passage leading to an outlet in the body. The spring force on the valve ball is controlled by adjusting the axial position of the gland (such as by screwing or unscrewing the gland into the valve body), thereby regulating the flow through the valve. Ball retainers and glands are usually made of brass or are separated from each other by springs.

To control the refrigerant flow, the diaphragm in the power element senses the refrigerant condition exiting the evaporator and corrects the flow rate to the evaporator by opening or closing the valve orifice. In certain bulb-free valves, the pressure pad is thermally conductive, and when refrigerant from the evaporator outlet passes around the pressure pad, thermal energy is transferred through the pad to the refrigerant fill in the head chamber above the diaphragm valve by conduction. In addition, a portion of the diaphragm surrounding the pressure pad is typically exposed to and directly in contact with the refrigerant from the evaporator outlet. The refrigerant pressure from the evaporator outlet to the diaphragm along with the force of the regulating spring on the valve element tends to close the valve and the pressure from the fill tends to open the valve. The balance of the force across the diaphragm along with the diaphragm's spring constant determines the deflection of the diaphragm and thus the opening of the expansion valve orifice between the condenser and the evaporator. The diaphragm is properly deflected to maintain a balance between these forces.

The pressure of the fill in the head chamber above the diaphragm valve is controlled by the pressure / temperature relationship of the gas (s) in the fill. The pressure pad is ideally at the same temperature as the refrigerant flowing through the valve, and as the refrigerant is in direct contact with the diaphragm, the temperature of the fill will generally follow the temperature of the refrigerant exiting the evaporator. Fucuda's US Pat. No. 6,223,994, Procter's US Pat. No. 3,691,783, Treader's US Pat. No. 3,537,645 and Otsu's US Pat. .
US Patent Publication No. 2222106 discloses an expansion device having a dynamic power rod. The patent summaries of Japanese Patent No. 08210734 and Japanese Patent No. 08210734 disclose an expansion valve having a brass pressure pad.

One problem with designers of bulbless expansion valves is the sensitivity of the valve to external conditions. For example, in a vehicle engine section, expansion valves have a detrimental effect on the operating characteristics of the valves and thus experience a temporary change in temperature that affects the performance of the system. This is believed to be attributable in part to the thermal energy provided by conduction from the surroundings surrounding the valve to the charge in the head chamber via the power element. Thermal energy from the vehicle engine is increased during engine operation, causing the temperature and pressure in the head chamber to be increased regardless of the damping effect of the pressure pad and direct contact with the diaphragm of the refrigerant. In such a situation, the valve opens more than desired, causing excess refrigerant to flow through the valve, resulting in liquid refrigerant to the compressor. Liquid refrigerant flowing into the compressor can be detrimental to the proper compression function and can affect the performance of the compressor, affecting the overall performance of the air conditioning system.

Attempts have been made to thermally closely couple the charges to the refrigerant to effectively use the refrigerant as a heat sink. One known technique is to use a highly conductive pressure pad made of aluminum, for example, to make the valve less sensitive to external conditions and more closely follow the temperature change of the refrigerant.

In doing so, however, the valve became quite sensitive to changes in temperature of the refrigerant. For example, aluminum pressure pads transfer thermal energy between a refrigerant and a charge at about the same time. This is also not good because the valve may be sensitive to hunting. In other words, there is a delay between the transient overheating in the low pressure refrigerant flow and the compensation adjustment of the expansion valve. Valves tend to be overcompensated in both directions. As can be appreciated, this also negatively affects the performance of the air conditioning system.

One of the main reasons for this sensitivity and hunting problem is believed to be the conventional way of forming pressure pads from aluminum. Although aluminum is an inexpensive, easily moldable material, it is not possible to prevent (or at least reduce) the hunting of the valve without having sufficient thermal mass to absorb the transient temperature change of the refrigerant.

Techniques are known which attempt to address the hunting problems of valves by aluminum pressure pads. One technique is to add heat transfer elements, such as plastic sleeves, around the fins of the pressure pad to reduce the rate of heat transfer. This improves the "hunting" of the valve, but complicates the fabrication.

The Applicant thus far considers that there has been a balance between achieving adequate sensitivity to the temperature of the refrigerant vapor in the valve and smooth operation of the valve to maintain proper control of the refrigerant flow of the refrigeration system. Accordingly, Applicant is a simple thermostatic expansion valve that overcomes the above problem, i.e. is less susceptible to transient changes in external temperature, in particular temperature fluctuations due to engine heat in the engine compartment and more appropriately to temperature changes of the refrigerant from the evaporator. I think there is industry demand for reactive valves.

A novel and unique temperature controlled expansion valve is provided which has a reduced sensitivity to external temperature transients, especially temperature fluctuations caused by engine heat in the engine compartment, and which responds appropriately to changes in temperature of the refrigerant from the evaporator.

According to the present invention, a temperature controlled expansion valve includes a pressure pad formed from a material having sufficient conductivity to prevent the valve from becoming too sensitive to external conditions and also having sufficient thermal mass to reduce the hunting of the valve. The pressure pad includes a solid cylindrical body, an enlarged head at one end and an elongated pin extending axially downward from the other end, all of which are preferably integrally formed from copper, copper alloy, or other material on one side. And the material is at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably at least about 170 W / mK (1200 BTU-in / hr-ft ² -F), better Preferably, a fusion, composite, mixture or mixture having a thermal conductivity of at least about 280 W / mK (2000 BTU-in / hr-ft ² -F) and a density of at least about 8 g / cm ³ (0.3 lb / in ³ ) or It can be another combination. Preferably, the pressure pad of the present invention is relatively simple to manufacture and has a moderate cost.

It is believed that the present invention overcomes many of the drawbacks of conventional devices by providing a novel and unique temperature controlled expansion valve. The valve has a reduced sensitivity to external temperature transients and responds more appropriately to changes in temperature of the refrigerant from the evaporator.

Additional features of the present invention will become apparent to those skilled in the art upon reviewing the following specification and accompanying drawings.

1 is a side cross-sectional view of an expansion valve constructed in accordance with the principles of the present invention.

2 is a side sectional view of a power element for an expansion valve;

3 is a side cross-sectional view of the pressure pad for the expansion valve.

4 is a graph of flow rate versus time for a representative temperature controlled expansion valve comprising a thermal mass power element formed in accordance with the present invention, as compared to representative power elements of the prior art.

5 is a graph of standardized flow rate versus time for a thermostatic expansion valve comprising a thermal mass power element formed in accordance with the present invention, compared to a representative thermostatic expansion valve of the prior art.

Referring to the drawings and initially to FIG. 1, in the air conditioning system, the refrigerant flows from the compressor 10 to the condenser 12 and from the condenser to the receiver / dryer 14 or inlet port of the temperature-controlled expansion valve, generally indicated at 16. (15) flows directly into. The expansion valve comprises a body 17 having a control sensing section, indicated at 18 and a metering section, indicated at 19. A ball valve assembly, generally indicated at 20, is disposed within the cavity 21 of the metering section, through a metering passage 22 defined between an inlet port 15 (condenser outlet) and an outlet port 23 (evaporator inlet). To control the flow. The valve assembly 20 includes a spring 24 for biasing the holder or cup 25 holding the ball valve 26 relative to the valve seat 27 to measure refrigerant flow through the passage 22. The spring 24 is supported in a spring seat 32 threadedly connected to the body 17 and sealed to it by an O-ring seal 32. The valve assembly 20 can be adjusted by rotating the spring seat 32 inward or outward of the body 17.

The ball valve is actuated by a pressure pin or stem 36 extending axially through the housing in sliding relationship with the inner bore 37. The O-ring elastomeric seal 38 is fluid sealed around the stem 36 in the bore 37 and held in place by the ring 39. The stem 36 is thus connected to a pressure pad 40 which is connected to the diaphragm 42 (see FIG. 2 or FIG. 3). The flow from the valve inlet port 23 in the metering section flows into the evaporator 46 and then passes into the inlet port 48 of the control sensing section of the body. The flow then passes through a return passage 50 that fluidly interconnects the outlet port 52 and the inlet port 48 and then directly back into the compressor 10 or through an evaporator outlet control valve (not shown). come.

The above-mentioned expansion valve is preferably a block valve formed of a suitable material such as metal (ie, aluminum alloy). The valve body is rectangular and typically located towards one end of the body, with the inlet and outlet ports 15, 23 of the metering section 19 on the two (usually opposed) side surfaces of the body 17, The inlet and outlet ports 48, 52 of the control sensing section 18 are on the same side surface as the respective inlet and outlet ports 15, 23, but are located towards the other end of the body 17. Mounting holes 54 are provided in the body for mounting the valve to the appropriate fixture of the system. The return passage 50 in the control sensing section 18 typically extends laterally through the body 17, that is to say when the expansion valve 16 is used in the vertical direction shown in FIG. 1. It should be noted that the passage 50 extends essentially horizontally through the valve.

The power element 55 is mounted integrally with the end surface of the body 17, preferably at its (upper) end. As shown in FIG. 2, the power element 55 comprises an annular diaphragm 42 mounted between an annular dome head or upper housing portion 62 and an annular support cup or lower housing portion 64. The diaphragm 42 is preferably formed of a thermally conductive material such as a metal (ie stainless steel), the periphery of which is sealed with the dome head 62 and the support cup 64 by soldering or brazing. The head chamber 70 is formed between the (top) surface of the diaphragm 42 and the dome head 62. The head chamber 70 is filled with a temperature reaction fill through an opening or a suitable capillary tube (not shown) and then sealed with a plug 72 or other suitable means.

On the other side of the diaphragm, an annular collar 73 is screwed into an axial control passage 74 (FIG. 1) formed in the upper end of the valve body 17 for mounting the power element to the valve body. Has The axial control passage 74 is a lateral passage 50 extending between the inlet port 48 and the outlet port 52 of the control sensing section with its inner end fluidly open. The O-ring seal 75 surrounds the outside of the support cup 64 of the body 17 and fluidically seals it. The support cup 64 and the other (lower) surface of the diaphragm 42 define a diaphragm chamber 76. The diaphragm chamber 76 is in fluid communication with the axial control passage 74.

According to the present invention, in order to maintain an adequate sensitivity to the temperature of the refrigerant flow through the valve and to reduce the sensitivity of the valve to hunting, the pressure pad 40 may be substantially like a fully mobile, copper alloy or other material. It is formed of a dense, high thermally conductive material, which material can be a fusion, composite, mixture, or other combination, at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably A thermal conductivity of at least about 170 W / mK (1200 BTU-in / hr-ft ² -F), more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ² -F) and at least about 8 g / cm ³ (0.3 lb / in ³ ). It has been found that forming pressure pads from such materials has particularly advantageous properties when used in temperature controlled expansion valves. These properties include: i) good thermal conductivity sufficient to closely connect the temperature of the refrigerant in the valve with the charging temperature to obtain a good sensitivity of the valve to the refrigerant, and ii) high conductivity but relatively low specific gravity, or relatively low specific gravity. It contains sufficient thermal mass so that the power element is not as susceptible to hunting as found in pressure pads formed of materials such as high but not high conductivity aluminum or conventional brass or bronze. Materials such as copper or copper alloys are particularly easy to work with and are reasonably costly.

As shown in FIG. 2, the pressure pad 40 includes a solid cylindrical body 77, a circular head 78 extending annularly at one (upper end) of the body 77, and a body 77. An elongated cylindrical pin or rod 79 protruding axially (down) from the other end of The body 77, the head 78, and the pin 79 are preferably machined, cast, stamped, molded or otherwise formed integrally together (in one piece), but brazing, soldering, adhesive bonding, heat or It can be formed into individual parts that can be bonded together or otherwise joined together by solvent melt bonding or mechanically. The body 77 of the pressure pad 40 is preferably arranged in the diaphragm chamber 76. The upper surface 80 of the head 78, which is in interview with the lower surface of the diaphragm 42, is thus intimately and thermally coupled directly to the diaphragm. The radial size of the head 78 relative to the diaphragm 42 may vary, and at least a small portion of the diaphragm surrounding the periphery of the base 78 is preferably exposed directly to the fluid flow in the chamber 76.

The pin 79 protrudes downward from the body 77 through the axial control passage 74 and the return passage 50. The pin 79 has a blind end bore formed inward from the distal end of the pin to receive the stem 36 (FIG. 1) of the valve assembly 20 such that the pin (and thus the pressure pad) is operatively coupled to the valve. 81). Stem 36 may remain fixed in bore 81 in any conventional manner, such as by pressing or screwing.

Further, preferably, the entire pressure pad is formed of a single piece of material or of a relatively high density so as not to be overly sensitive to temperature gradients, or assembled into separate parts. That is, due to the relatively high thermal mass of the pressure pad thus formed, the material provides smooth operation of the valve.

In addition to copper, and copper alloys such as brass or bronze, other suitable materials include other metals and alloys, such as aluminum and stainless steel, and may also be oxides, carbon, and their allotrope such as graphite and diamond and thermoplastic or thermoset In addition to plastics and other polymeric materials, nonmetals such as ceramics are widely used herein to include nitrides, carbides and borides. Two or more other copper or copper alloys, or two or more other metals or alloys, ceramics, carbon or carbon allotropees, or combinations of two or more such materials, such as polymeric materials or plastics, may also be suitable, and also one or more metals Combinations of one or more such materials, such as one or more base metals, and one or more other such materials may also be considered to be within the scope of the present invention. Such combination may be a mixture, alloy, admixture, copolymer, or composite.

In the case of a unitary structure of pressure pads, the pads may be formed entirely of the above-mentioned materials and may be formed in a layered or other structure as a whole, homogeneously or as a coating provided on the core. If the pad is formed as an assembly of separate parts, each of the parts may be formed of the same or different material.

In the case of a single material or combination of materials, the material itself is at least about 115 W / mK (800 BTU-in / hr-ft ² -F) in volume, preferably at least about 170 W / mK (1200 BTU-in / hr-ft ^2- ° F, more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ^2- ° F) thermal conductivity, and at least about 8 g / cm 3 (0.3 1b / in ³ ) It may be selected, formed or combined to indicate the density of. In this regard, similarly formed guide pads per se are at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably at least about 170 W / mK (1200 BTU-in / hr- ft ^2- ° F, more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ^2- ° F) total thermal conductivity, and at least about 8 g / cm 3 (0.3 1b / in ³ ) Can be represented. In the case of an assembly, the material of each of the individual parts is at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably at least about 170 W / mK (1200 BTU-in / hr-). ft ² -F), more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ² -F) thermal conductivity, and at least about 8 g / cm 3 (0.3 1b / in ³ ) It may be selected, formed or combined to represent each. Otherwise, the material may be at least about 115 W / mK (800 BTU-in / hr-ft ² -F), preferably at least about 170 W / mK (1200 BTU-in / hr-ft ^2- ). Fahrenheit), more preferably at least about 280 W / mK (2000 BTU-in / hr-ft ² -F), and a density of at least about 8 g / cm 3 (0.3 1b / in ³ ). May be selected, formed or combined. For reasons of economy and ease of manufacture, copper, or alloys or other materials comprising copper, may be considered to be good.

Some of the refrigerant entering the inlet port 48 from the evaporator outlet generally branches from the flow path through the passage 50 and flows through the passage 74 into the diaphragm chamber 76. The refrigerant in the chamber 76 is in direct contact with the lower surface of the diaphragm 42 around the lower surface of the body 77 and the head 78, and around the periphery of the head 78. The refrigerant then exits chamber 76 and passage 74 and recombines with the flow through passage 50 to pass through the outlet port 52 to the compressor inlet. The refrigerant pressure on the diaphragm 42 and the lower surface of the head 78 through the port 48 from the evaporator outlet, together with the force of the regulating spring 24 against the valve element, causes the ball valve to rest against the seat 27. Pressurize. On the other hand, the pressure from the fill of the chamber 70, which is affected by heat transfer through the exposed portion of the pressure pad 40 and the diaphragm 42, opens the valve. The balance of the force across the diaphragm along with the diaphragm's spring constant determines the deflection of the diaphragm and thus the opening of the expansion valve orifice between the condenser and the evaporator. The diaphragm is properly deflected to maintain a balance between these forces.

In addition, copper, copper alloy or other pressure pads formed in accordance with the inventive concept have a good thermal conductivity such that the fill of the head chamber 70 is thermally coupled to the refrigerant, so that it follows the temperature of the refrigerant rather than the ambient temperature. . The thermal mass of these pressure pads weakens or stabilizes the effect of the temperature transients of the refrigerant, causing a time delay or other form of delay in substantially the transfer of temperature changes to the fill. As a result, the fill of the head chamber is less sensitive to external temperature influences and follows the temperature of the refrigerant leaving the evaporator flat.

The following examples, all percentages and ratios by weight unless otherwise indicated, are intended to illustrate the implementation of the present invention in connection with the present application, and are not intended to limit the scope thereof.

example

Example 1

Thermal mass power elements with pressure pads of the structure generally shown in FIGS. 2 and 3 are composed of aluminum (type 6061), free cutting brass (type C360000), and tellurium (type C14500). These power elements are essentially identical except for the constituent material of the pressure pad. The properties of these materials that make up the pads are given in Table 1 below.

Table 1

material Density g / cm ³ (lb / in ³ ) Thermal Conductivity W / mK (BTU-in / hr-ft ^2- ℉) aluminum 2.7 (0.0975) 280 (1250) Brass 8.5 (0.307) 115 (798) copper 8.9 (0.323) 350 (2460)

The material has a drop in density and thermal conductivity within the range understood by the present invention. Therefore, power elements including copper pressure pads are considered representative of the present invention.

This power element is installed in the configured temperature controlled expansion valve. The valve is then installed in a conventional vehicular cooling system (refrigerant R-134a) placed in an insulated enclosure with a heat source external to the system. The system operates until steady flow is reached, and the ambient temperature in the enclosure surrounding the valve rises to about 120 ° C (250 ° F). When the ambient temperature increases the temperature of the power element, the accompanying high temperature causes the valve to open wide and more refrigerant flows into the evaporator. As the flow increases, it eventually cools the element, lowers the pressure, and becomes a periodic response over time.

The measured response to the different pressure pads is shown in FIG. 4 as a comparison graph of flow rate versus time. Each trace for brass, aluminum and copper pads is labeled 110, 112 and 114, respectively, for ease of reference.

As can be seen in FIG. 4, the size of the cycle is small for copper 114 having both high density and high thermal conductivity. In contrast, aluminum 112 has a high thermal conductivity but a low density, reacts quickly and changes, and is easily affected by the sensitivity of the atmosphere. Brass 110 reacts more slowly with lower thermal conductivity than aluminum, but functions very similar to aluminum when combined with high density.

For the copper pad, the theory is not limited and the heat transferred from the atmosphere due to the high thermal conductivity can be conducted from the refrigerant flowing through the valve. The high density, and thus the high thermal mass of the pad, prevents the power element form from undergoing rapid changes in temperature, which enters the system externally or internally, ie within the system. However, due to the high thermal conductivity, the valve responds appropriately to the needs of the system but need not be overly sensitive to changes in the system.

Example 2

The performance of a representative commercial valve is compared with that of a valve with a copper pad according to the present invention. The valve is tested to allow a direct comparison of the reactions with the flow rate for the standardized R-134a refrigerant by subtracting the observed average flow rate, essentially as described in Example 1. These reactions are shown graphically in FIG. 5 according to a standardized flow versus time graph. The valves tested are also described in Table 2 according to the number of traces shown in FIG.

Table 2

valve Trace Explanation Hollow ¹ 120 Hollow Pin Element (U.S. Patent 5,269,459) Brass # 1 122 Solid Brass (C36000) Pressure Pad Phosphor Bronze 124 Solid Phosphor Bronze (C54400 ¹ ) Thermal Mass Pressure Pad Aluminum # 1 126 Solid Aluminum (6061) Pressure Pad Brass # 2 128 Solid Brass (C3600) Thermal Mass Pressure Pads (larger than Brass # 1) Aluminum # 2 130 Solid aluminum (6061) pressure pad (larger than aluminum # 1) copper 132 Solid Copper (C14500) Thermal Mass Pressure Pad

¹ density: 8.9 g / cm ³ (0.321 lb / in ³ ); Thermal Conduction: 87 W / mK (604 BTU-in / hr-ft ^2- ℉)

Referring to Figure 5, the hollow pin valve 120 appears most stable. In this respect, it is expected that the coolant in the power element is moved to the coldest spot, ie the bottom of the fin in the coolant flow airflow. This allows the valve to maintain control based on the temperature of the refrigerant rather than the atmosphere. However, hollow pin designs are relatively complex and expensive to manufacture.

The aluminum # 1 valve 126 is shown to deviate most from the average initial flow set point (shown as "0" on the flow axis). The pressure pad in this design is almost massless and the heat is a relatively small piece of aluminum that conducts well.

The brass # 1 valve 122 has a brass pad that is larger than the aluminum # 1 valve, but with a volume smaller than that of the brass thermal mass pressure pad valve (brass # 2, 128).

The aluminum # 2 valve 130, the copper valve 132, the brass # 2 valve 128 and the phosphor bronze valve 124 have thermal mass pressure pads having a larger volume than other valves. Aluminum reacts fast because of its high thermal conductivity. Phosphor Bronze pads absorb heat, but do not transfer well to the refrigerant flow stream, resulting in more breakdown compared to other thermal mass valves.

Brass pads have slightly higher thermal conductivity, so they can have better thermal conductivity than aluminum and copper pads as well as phosphor bronze. In addition, the copper pad according to the present invention has the highest thermal conductivity, so that the best heat transfer from the atmosphere to the refrigerant flow airflow can be best controlled the flow. The higher density of the copper pads means that during heat conduction, the larger mass is thermally more stable and therefore does not react immediately to temperature changes like aluminum pads, resulting in more stable operation. As a result, the copper pads represented in the specification of the present invention included exhibit similar performance to hollow pin designs, but are less expensive and easier to manufacture.

Thus, as noted above, the present invention minimizes the sensitivity of the valve to external temperature transients, i.e., resists changes in ambient temperature and appropriately corresponds to changes in temperature in the refrigerant flow, i.e. " hunting " or other oscillatory Provides a new and unique thermostatic expansion valve that is effective and otherwise stable in operation. The expansion valve of the present invention can achieve this result in a simple and cost-effective manner without complicated hardware and without difficulty or time consuming manufacturing or assembly steps.

Basic and preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention intended to be protected in this specification is not intended to be limited to the specific forms set forth as considered to be limited. As disclosed in the appended claims, modifications and variations may be made by those skilled in the art without departing from the scope and spirit of the present invention. All references, including any priority documents cited herein, are expressly incorporated by reference.

Claims (29)

A metering passage 22 fluidly connecting the condenser outlet port 15 and the evaporator inlet port 23, and a return passage 50 fluidly connecting the evaporator outlet port 46 and the compressor inlet port 52, A valve body 17 further comprising a control passage 74 fluidly connected to the return passage 50; A diaphragm housing portion (62, 64) mounted to the valve body (17) and supporting the diaphragm (42), wherein one housing portion (62) includes a fluid fill with one surface of the diaphragm (42). Define a head chamber 70, another housing portion 64 cooperates with the body 17 together with the other surface of the diaphragm 42 to define the diaphragm chamber 76, and the control passage 74 defines the diaphragm chamber. A power element 55 in fluid communication with the 76 and return passage 50, In the valve bore 37 extending between the metering passage 22 and the return passage 50, allowing fluid flow through the metering passage 22 from a first position that prevents fluid flow through the metering passage 22. A valve assembly (20) having a valve element (26) disposed in said metering passage (22) that is movable to a second position; An enlarged head at least partially disposed in the return passage 50, i) at one end of the body 77 and ii) at one end of the pressure pad body 77 disposed relative to the diaphragm 42; 78 and iii) a pressure pad 40 which includes a pin 79 integral with the other end of the pressure pad body 77 and extending from the end thereof and operatively connected to the valve element 26. In the temperature control expansion valve 16, The pressure pad 40 has a thermal conductivity of at least 170 W / mK (1200 BTU-in / hr-ft ² -F) and a density of at least 8 g / cm ³ (0.3 lb / in ³ ) Expansion valve (16). The temperature-controlled expansion valve (16) of claim 1, wherein the pin (79) of the pressure pad (40), the pressure pad body (77), and the head (78) are integral. The temperature-controlled expansion valve (16) of claim 2, wherein the pressure pad body (77) is a solid cylinder. delete delete delete delete delete delete The temperature controlled expansion valve (16) of claim 1, wherein the pressure pad (40) has a thermal conductivity of at least 2000 280 W / mK (2000 BTU-in / hr-ft ² -F). delete delete The heat sink of claim 1, wherein at least one of the pressure pad body 77, the pin 79, and the head 78 is substantially in total of at least 1200 BTU-in / hr-ft ^2- ° F of 170 W / mK. A temperature controlled expansion valve (16) formed from a material having conductivity and a density of at least 8 g / cm ³ (0.3 lb / in ³ ). The pressure pad (40) of claim 2, wherein the pressure pad (40) is substantially at least a thermal conductivity of at least 280 W / mK (2000 BTU-in / hr-ft ² -F) and at least 8 g / cm ³ (0.3 lb / in ³ ). Thermostatic expansion valve 16 formed of a material having a density. The pressure pad (40) of claim 2, wherein the pressure pad (40) is substantially at least 170 W / mK (1200 BTU-in / hr-ft ² -F) of thermal conductivity and 8 g / cm ³ (0.3 lb / in ³ ) or more. Thermostatic expansion valve 16 formed of a material having a density. A metering passage 22 having a pair of side surfaces and upper and lower end faces, which fluidly connects the condenser outlet port 15 on one side and the evaporator inlet port 23 on the other side, and the evaporator outlet port on the one side. A valve body 17 including a return passage 50 fluidly connecting the 46 and a compressor inlet port 52 on the other side, and further comprising a control passage 74 fluidly connected to the return passage 50. Wow, A diaphragm 42 mounted on one end surface of the body 17 and supported by an outer dome head 62 and an inner support cup 64, wherein the dome head 62 and the diaphragm 42 are provided. The outer surface of the confinement defines a fill chamber 70 for receiving fluid fill, the support cup 64 and the inner surface of the diaphragm 42 cooperate with the valve body 17 to surround the diaphragm chamber 76, The control passage 74 includes a power element 55 fluidly connecting the diaphragm chamber 76 and the return passage 50; The metering passage from the first position having a valve stem 36 disposed in the valve bore 37 extending between the metering passage 22 and the return passage 50 and preventing fluid flow through the metering passage 22. A valve assembly (20) comprising a valve element (26) at one end of the valve stem (36) in the metering passage (22) that is movable to a second position to enable fluid flow through the (22); Present in the other end of the valve stem in thermal contact with the inner surface of the diaphragm 42 and in thermal contact with the fluid flowing through the return passage 50, i) a solid type disposed within the diaphragm chamber 76 Integral with the cylindrical body 77, ii) an enlarged circular head 78 at one end of the pressure pad body 77 disposed in face-to-face contact with the diaphragm 42, and iii) the other end of the pressure pad body 77. Integral pressure pad including a cylindrical pin 79 that is axially extending axially away from the other end of the pressure pad body 77 and into the return passage 50 and operably connected to the valve element 26. A temperature controlled expansion valve (16) comprising 40, The pressure pad 40 has a thermal conductivity of at least 170 W / mK (1200 BTU-in / hr-ft ² -F) and a density of at least 8 g / cm ³ (0.3 lb / in ³ ) Expansion valve (16). delete delete delete The temperature controlled expansion valve (16) of claim 16, wherein the pressure pad (40) has a thermal conductivity of at least 2000 280 W / mK (2000 BTU-in / hr-ft ² -F). delete The pressure pad 40 of claim 16, wherein the pressure pad 40 is substantially in its entirety greater than or equal to 280 W / mK (2000 BTU-in / hr-ft ² -F) thermal conductivity and greater than or equal to 8 g / cm ³ (0.3 lb / in ³ ). Thermostatic expansion valve 16 formed of a material having a density. 18. The pressure pad 40 of claim 16, wherein the pressure pad 40 is substantially at least 170 W / mK (1200 BTU-in / hr-ft ² -F) thermal conductivity and 8 g / cm ³ (0.3 lb / in ³ ) or more. Thermostatic expansion valve 16 formed of a material having a density. 14. The thermostatic expansion valve (16) of claim 13, wherein the material comprises at least one metal, at least one metal alloy, at least one ceramic, carbon, at least one carbon allotrope, at least one polymeric material, or a combination thereof. The temperature-controlled expansion valve (16) of claim 13, wherein the material comprises copper. The temperature-controlled expansion valve (16) of claim 15, wherein the material comprises at least one metal, at least one metal alloy, at least one ceramic, carbon, at least one carbon allotrope, at least one polymeric material, or a combination thereof. 16. The temperature-controlled expansion valve (16) of claim 15, wherein said material comprises copper. 24. The thermostatic expansion valve (16) of claim 23, wherein the material comprises one or more metals, one or more metal alloys, one or more ceramics, one or more carbon allotrope, one or more polymeric materials, or a combination thereof. 24. The temperature regulating expansion valve (16) of claim 23, wherein said material comprises copper.

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