JP2676887B2 - Expansion valve - Google Patents

Description

TECHNICAL FIELD The present invention relates to an expansion valve for expanding a high-pressure fluid into a low-pressure fluid, and is used as a refrigerant expansion valve in a refrigeration cycle of an air conditioner such as a car air conditioner. It is a thing.

[Conventional technology]

This type of expansion valve is disclosed, for example, in No. 11 of Japanese Patent Publication No. 53-45539.
As shown in FIG. 12 and FIG. 12, an inlet side for receiving a high-pressure fluid, that is, a high-pressure passage and a downstream end of the high-pressure passage are provided in communication with each other to adjust the flow rate of the high-pressure fluid and Is provided with an outlet side, that is, a low-pressure side passage, which is arranged in communication with the downstream end of the valve mechanism and which delivers the expanded low-pressure fluid. It should be noted that it is generally composed of an orifice for restricting the flow of fluid and a valve member arranged so as to be capable of advancing and retracting with respect to the orifice so as to adjust the flow rate through the orifice.

Next, the function of the expansion valve will be briefly described. By injecting the fluid in the high temperature and high pressure state from the orifice, the fluid expands rapidly. At that time, the injection amount of the particles from the orifice is adjusted by the valve member. Then, the rapidly expanded fluid becomes a low-temperature low-pressure mist-like fluid.

The pressure on the downstream side of the expansion valve is set by the degree to which the valve member throttles the orifice. The lower the set pressure, the more the flow of high-pressure fluid is throttled, the flow velocity through the orifice increases, and the pressure decreases. . At that time, the so-called “icing phenomenon” is apt to occur, in which the water contained in the fluid freezes, causing the expansion valve outlet side passage to be in a negative pressure state, that is, a state in which the refrigerant does not flow. When this phenomenon occurs, problems such as abnormal heating of the compressor and poor cooling may occur.

Conventionally, as pointed out in JP-A-62-131163 and JP-A-62-266369, this icing phenomenon is caused by the valve mechanism.
That is, it has been considered that the water in the fluid freezes on the valve to close the gap between the valve member and the inner peripheral surface of the orifice or the valve seat.

[Problems to be solved by the invention]

However, when the inventors actually manufactured an expansion valve with a transparent member and confirmed by experiments where in the interior the icing phenomenon occurs, it was confirmed that the fluid inside the atomized fluid was not on the outlet passage wall surface but around the valve. It was clarified that this occurs due to the adhesion of water and freezing.

The present invention has been made in view of the above facts, and an object of the present invention is to provide an expansion valve in which the icing phenomenon does not occur even when water is mixed in the fluid.

[Means for solving the problem]

In order to achieve the above object, the present invention is arranged so as to communicate with an inlet-side passage for receiving a high-pressure fluid and a downstream end of the inlet-side passage for adjusting the flow rate of the high-pressure fluid and expanding the high-pressure fluid. An expansion valve provided with an atomizing valve mechanism and an outlet-side passage that communicates with a downstream end of the valve mechanism and delivers the expanded low-pressure fluid, wherein the outlet-side passage has poor water wettability. The technical means of providing a water repellent means will be adopted.

[Action]

Due to the water repellency of the outlet side passage due to the water disabling means, the freezing of the water contained in the fluid is prevented, and therefore the icing phenomenon occurs even when the set pressure of the expansion valve is very low. Does not occur.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a general refrigeration cycle for car air conditioners in which a refrigerant expansion valve is used will be briefly described with reference to FIG.
The refrigeration cycle has a compressor 1, and the refrigerant sucked into the compressor 1 as a gas is compressed by the compressor 1 and is sent to a condenser 3 through a pipe 2 where the air sent from a fan 3a is used. It is cooled and condensed to become a liquid refrigerant. This liquid refrigerant is sent to the liquid receiver 5 through the line 4, and is stored therein as a high-pressure liquid. The high-pressure refrigerant liquid then enters the expansion valve 7 through the high-pressure side pipe 6, and the refrigerant that has expanded through the expansion valve 7 flows through the low-pressure side pipe 8 in a liquid phase state in which a partial gas phase is mixed. Through which the heat is taken from the air sent from the fan 9a to evaporate into a substantially complete gas, which then returns to the compressor 1 through the pipe 10, and thus the refrigeration cycle is completed. Done. The expansion valve 7 opens when the pressure on the downstream side decreases to the constant pressure and maintains the downstream pressure at the set pressure. In FIG. 2, reference numeral 11 is a temperature sensitive cylinder, and 12 is an electromagnetic clutch for connecting and disconnecting the power transmission between the compressor 11 and the automobile engine.

Next, the structure of the expansion valve 7 showing an embodiment of the present invention will be described with reference to FIG. In FIG. 1, the expansion valve 7
Is a valve main body 13 made of metal such as copper, an inlet side passage provided in the valve main body 13, that is, a high pressure side refrigerant passage 14, and a longitudinal axis line substantially perpendicular to the longitudinal axis line of the passage 14. The outlet side passage, that is, the low pressure side refrigerant passage 15 is provided, and the high pressure side refrigerant passage 14 is connected to the high pressure side pipeline 6 shown in FIG.
The low pressure side refrigerant passage 15 is connected to the low pressure side pipe line 8 shown in FIG. Further, in the valve body 13, an orifice 17 arranged concentrically with respect to the longitudinal axis of the high pressure side refrigerant passage 14 is provided, and the orifice 17 has an upstream end opening to the high pressure side refrigerant passage 14 and a low pressure side. It has a downstream end opening to the refrigerant passage 15, and makes both passages 14 and 15 communicate with each other. At the upstream end of the orifice 17, a valve seat 18 continuous with the inner peripheral surface of the orifice 17 is provided,
A spherical valve member 19 made of stainless steel is disposed in the high pressure side refrigerant passage 14 and associated with the valve seat 18. Then, the inner wall surface of the low-pressure side refrigerant passage 15 is coated with a fluororesin coating 16 having poor water wettability.

Further, the valve receiving member 20, and thus the valve member 19, has an annular spring receiving member 21 made of metal such as copper screwed into the high pressure side refrigerant passage 14.
The pressing force of the spring 22 against the valve member 19, which is spring-loaded in the direction of the valve seat 18 by the compression coil spring 22 interposed between and, is adjusted by changing the position of the spring receiver 21. The valve opening direction of the valve member 19 is opposite to the flow direction of the high-pressure refrigerant flowing through the orifice 17. As shown in FIG. 1, a recess is formed in the upper surface of the valve body 13, and a cover member 23 is attached to the recess to define a space 24 together with the recess, and a metal is provided in the space 24. A diaphragm 25 made of metal is provided and divides this space 24 into two chambers 26 and 27. One of the chambers 26 has a second member attached to the cover member 23.
A pressure signal from the temperature sensitive tube 11 is introduced through a conduit 28 shown in the figure, and the other chamber 27 is connected to the low pressure side refrigerant passage 15 through a passage 29 provided in the valve body 13. The pressure in the low-pressure side refrigerant passage, that is, the evaporation pressure, is in communication with the chamber.
It will be introduced in 27. A pad member 30 which is in contact with the diaphragm 25 is provided in the chamber 27, and a valve rod 31 is in contact with the pad member 30. The valve rod 31 is slidably fitted in a hole provided in the valve body 13 and
The lower end of 31 is brought into contact with the top surface of the valve member 19. The temperature sensitive tube 11 emits a pressure new pole corresponding to the refrigerant temperature at the inlet side of the compressor 1, and the pressure signal thereof enters the one chamber 26 through the conduit 28 and one side (upper surface) of the diaphragm 25. Act on. Further, the pressure in the low-pressure side refrigerant passage 15 acts on the other surface (lower surface) of the diaphragm 25 via the passage 29. Therefore, the diaphragm 25 moves up and down due to the pressure difference acting on both the upper and lower surfaces thereof. Is displaced to. This diaphragm
The displacement of 25 is due to the contact member 30 and the valve rod 31 that is in contact with it.
Is transmitted to the valve member 19 via the valve member 19 with respect to the valve seat 18.
The position of is adjusted. Thus, the clearance between the valve seat 18 and the valve member 19 is adjusted, thereby controlling the flow rate of the refrigerant through the orifice 17.

Next, the operation of the above-described embodiment will be described with reference to FIGS. When the temperature-sensing cylinder 11 senses a rise in the refrigerant temperature on the inlet side of the compressor 1, a pressure signal corresponding to that is detected by the conduit 28.
Flow into the chamber 26 of the expansion valve 7 to displace the diaphragm 25 in the direction of approaching the valve body 13 against the force of the spring 22, and this displacement is caused by the contact member 30 and the valve rod 31. The valve member 19 is moved to the direction away from the orifice 17 by being transmitted to the valve member 19, so that the clearance between the valve member 19 and the valve seat 18 is increased and the flow rate of the refrigerant through the orifice 17 is increased. On the contrary, when the temperature sensitive tube 11 senses the decrease of the refrigerant temperature on the inlet side of the compressor 1, a pressure signal corresponding thereto is mixed into the chamber 26 to displace the diaphragm 25 in the direction away from the valve body 13, As a result, the valve member 19 is moved in the direction closer to the orifice 17 by the spring 22 to reduce the gap between the valve member 19 and the valve seat 18, thereby reducing the flow rate of the refrigerant passing through the orifice 17. The refrigerant is ejected from the orifice 17 into the low-pressure side refrigerant passage 15 and is rapidly expanded into a mist. At that time, the water contained in the refrigerant comes into contact with the inner wall surface of the low-pressure side refrigerant passage 15, but since the inner wall surface is coated with a fluororesin coating 16 having poor water wettability, it does not adhere. . As a result, it is possible to avoid the phenomenon that the water freezes and the flow passage area is reduced.

Although the inner wall surface of the low pressure side refrigerant passage 15 is coated with fluororesin 16 in the above embodiment, a pipe of fluororesin material may be inserted. The pipe has a hole for a passage for transmitting the pressure in the low pressure side refrigerant passage to the lower surface of the diaphragm.

Further, in the above embodiment, the valve mechanism is arranged on the upstream side of the orifice, that is, on the high pressure side.
As shown in the figure, the present invention may be applied to the valve mechanism arranged downstream of the orifice, that is, on the low pressure side. In FIG. 3, 32 is a valve support, 33 is a leg,
Other reference numerals are the same as those shown in FIG. The valve opening direction of the valve member 19 is the same as the flow direction of the high-pressure refrigerant flowing through the orifice 17. In this case, the inner wall surface of the low pressure side refrigerant passage 15 is treated with a material having poor water wettability such as fluororesin as shown in the above-mentioned embodiment, and the component parts (third part) located in the low pressure side refrigerant passage 15 are treated. In the figure, 20, 21, 22, 32) are all treated with a material having poor wettability such as a fluororesin.

〔The invention's effect〕

In the expansion valve according to the present invention, since the wettability of the inner wall of the outlet side refrigerant passage to which the water contained in the fluid adheres is deteriorated by the anaerobic means, the water does not adhere,
Therefore, there is an excellent effect that it is possible to prevent an increase in flow load due to freezing of water.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the configuration of an embodiment of an expansion valve according to the present invention, and FIG. 2 is a diagram showing a circuit configuration of a refrigeration cycle for a car air conditioner using the expansion valve shown in FIG. 1, FIG. 3 is a vertical cross-sectional view of an expansion valve having a different structure to which the present invention is applied. 7 …… Expansion valve, 9 …… Evaporator, 13 …… Valve body, 14 …… High pressure (inlet) side refrigerant passage, 15 …… Low pressure (outlet) side refrigerant passage, 16
…… Fluororesin coating, 17 …… Orifice, 18 ……
Valve seat, 19 …… Valve member, 20 …… Valve seat, 21 …… Spring seat, 22 …… Spring.

Claims (3)

(57) [Claims] 1. A valve, which is provided in communication with an inlet-side passage for receiving a high-pressure fluid and a downstream end of the inlet-side passage, adjusts a flow rate of the high-pressure fluid, and expands the high-pressure fluid into an atomized state. The mechanism and the downstream end of the valve mechanism are communicated with each other,
An expansion valve provided with an outlet-side passage for delivering expanded low-pressure fluid, characterized in that the outlet-side passage is provided with anaerobic means having poor water wettability. 2. The expansion valve according to claim 1, wherein the anaerobic means coats an inner wall surface of the outlet side passageway with a fluororesin. 3. The expansion valve according to claim 1, wherein the anaerobic means inserts a fluororesin pipe into the outlet side passage without leaving a gap with an inner wall surface thereof.