JPH0914495A - Block type expansion valve and air conditioner - Google Patents

Abstract

PURPOSE: To suppress abnormal increase of high side pressure without discharging coolant from a refrigeration cycle to the outside by housing a safety valve mechanism which is opened when pressure difference between a liquid passage and a gas passage 96 is a specified value or more. CONSTITUTION: A valve body 9 has a liquid pipe connection port 91 and a gas pipe connection port 94. A bypass passage 97 is arranged between a liquid passage 95 and a gas passage 96, while a seat surface 98 is formed on the bypass passage 97 at its opening on the side of the gas passage 96. A safety valve mechanism 8 is composed of a packing 81 which closes the seat surface 98, a valve bar 82, a cylindrical coil spring 83, and a pressing plate 84. In the safety valve mechanism 8, the valve bar 82 is pressed up when pressure difference between the high pressure liquid passage 95 and the low pressure gas passage 96 is a specified value or more, and the seat surface 98 is opened. A part of high pressure coolant inside the liquid passage 95 is flowed out to the gas passage 96 through the bypass passage 97, for decreasing the high pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block type expansion valve and an air conditioner using the same.

[0002]

2. Description of the Related Art Generally, a temperature type automatic expansion valve is used for controlling the flow rate of the refrigerant in a refrigeration cycle of an air conditioner such as a room air conditioner or a car air conditioner, and controls so that the superheat degree of the gas refrigerant at the outlet of the evaporator becomes constant. To be done. Recently, in a car air conditioner, a block type expansion valve, which is a block of the temperature type automatic expansion valve, is used in terms of serviceability.

FIG. 2 is a system diagram of a refrigerating cycle provided with the block type expansion valve, and the block type expansion valve is shown in a longitudinal sectional view. In the figure, 1 is a compressor, 2 is a condenser connected to the same compressor, 3 is a receiver connected to the same compressor, 4 is a block type expansion valve connected to the same receiver via a liquid pipe connection port 91, and 5 is a same block type An evaporator connected to the expansion valve via an evaporator inlet connection 92, an outlet of the evaporator is connected to the block expansion valve again via an evaporator outlet connection 93, and the compressor 1 is connected via a gas pipe connection 94. Connected to the block type expansion valve 4. Reference numeral 6 is a relief valve provided in the compressor.

In the block type expansion valve 4, 41 is a valve body, 42 is a power element provided on the upper part,
Reference numeral 43 is a temperature sensitive rod forming a part of the power element, 43a is a temperature sensitive portion of the temperature sensitive rod, 44 is an orifice through which the lower portion of the temperature sensitive rod is inserted, and 45 is provided at the tip of the lower portion of the temperature sensitive rod. Ball, 46 is a cylindrical coil spring that pushes the ball upward, 47 is a superheat adjusting screw that supports the lower end of the spring, 48 is a power element 42, and the temperature sensing rod 4 is provided.
A diaphragm provided in contact with the upper end of 3 and 49 are gaseous refrigerant filled in a space between the lid of the power element 42 and the diaphragm 48.

In this system, when the power of a running engine (not shown) is transmitted through a pulley and a magnet clutch (not shown) to drive the compressor 1,
The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows as shown by the arrow, first enters the condenser 2, and is condensed and liquefied by being cooled by the outside air introduced by a fan (not shown). After being stored in the receiver 3, this liquid refrigerant enters the block type expansion valve 4 and is adiabatically expanded by being throttled by the orifice 44 inside the block expansion valve 4 to become a low-temperature low-pressure gas-liquid two-phase state.
to go into. Here, the air inside the passenger compartment introduced by a fan (not shown) is cooled to evaporate, and returns to the compressor 1 via the temperature sensing portion 43a of the block type expansion valve 4.

The control method of the expansion valve 4 is as follows. A change in the refrigerant temperature at the outlet of the evaporator 5 is detected by the temperature sensitive portion 43a of the temperature sensitive rod 43, transmitted to the upper portion, and transmitted to the enclosed refrigerant 49 in the power element 42 via the diaphragm 48,
As a result, the volume expansion and contraction of the enclosed refrigerant 49 shifts to a change in the downward force on the diaphragm 48, and the ball 45 at the tip of the temperature sensitive rod 43 is moved up and down to open and close the orifice 44. Evaporation pressure and the restoring force of the cylindrical coil spring 46 act on the diaphragm 48 as an upward force and are set by changing the restoring force of the cylindrical coil spring 46 by screwing or unscrewing the superheat adjusting screw 47. Superheat control is performed so that a predetermined superheat (for example, 5 ° C.) is achieved.

FIG. 3 is a longitudinal sectional view of an example of the relief valve 6 attached to the compressor 1 in FIG. A relief valve 6 is attached to the main body of the compressor 1 as a safety device on the high pressure side in the refrigeration cycle. When the pressure of the refrigerant discharged from the compressor 1 rises abnormally to a predetermined value or more, the relief valve 6 is opened to open the inside of the refrigeration cycle. The refrigerant is released into the atmosphere. In the figure, the relief valve 6 includes a valve body 61, a valve 62, and a packing 6.
3, a cylindrical coil spring 64, a holding plate 65, etc., and a valve body 61 is provided with a gas inlet 66 and a mounting screw 67. The mounting screw 67 is screwed into the main body of the compressor 1 or the high-pressure side pipe for mounting.

In this apparatus, a high pressure side pressure of the refrigerant is applied from the gas inlet 66, and when this pressure exceeds a predetermined value, the restoring force of the cylindrical coil spring 64 is overcome and the valve 62 is pushed up to open the valve 62. Then, the high-pressure refrigerant gas passes through the groove 62 a provided in the peripheral portion of the valve 62, between the springs 64, and the escape hole 65 provided in the central portion of the holding plate 65.
It is released from a into the atmosphere.

[0009]

In the above conventional air conditioner and refrigeration system, since the relief valve 6 is attached to the main body of the compressor 1 or the high pressure side pipe as a high pressure side safety device, the following drawbacks occur. there were. (1) When the high-pressure side pressure in the refrigeration cycle rises abnormally, the refrigerant in the refrigeration cycle is released into the atmosphere,
As it is, the air conditioner and the refrigeration system cannot be reused, and the refrigerant needs to be recharged for reuse. (2) In the case of a vehicle air conditioner, the compressor 1 and the high-pressure side piping are installed in the engine room of the vehicle, so white smoke is generated when the discharged refrigerant and lubricating oil hit a hot object in the engine room. If it hits or hits the belt, it may cause slippage.

The present invention solves the above-mentioned drawbacks of the prior art, reduces the abnormal increase in the high-pressure side pressure without releasing the refrigerant from the refrigeration cycle to the outside, and enables the immediate reuse of the air conditioner, and This is to prevent an abnormal occurrence in the engine room.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above problems and relates to an air conditioner having a block type expansion valve having the following features. (1) A liquid refrigerant channel and a gas refrigerant channel are built in the valve body, and the refrigerant outlet refrigerant temperature is sensed in the gas refrigerant channel to maintain the refrigerant superheat degree at the evaporator outlet at a set value. In the block type expansion valve for controlling the flow rate, a bypass passage that connects the liquid refrigerant passage and the gas refrigerant passage is provided in the valve body, and the high pressure P ₁ in the liquid refrigerant passage and the gas refrigerant passage are provided. Low pressure P inside
_2. A block type expansion valve, characterized in that a safety valve mechanism that opens when a pressure difference ΔP (= P ₁ −P ₂ ) from ₂ is equal to or greater than a predetermined value is provided in the bypass passage. (2) An air conditioner equipped with the block type expansion valve with a safety valve mechanism according to the above item (1).

[0012]

Since the present invention has the above configuration,
When the pressure difference ΔP (= P ₁ −P ₂ ) between the high pressure P ₁ and the low pressure P ₂ during the refrigeration cycle rises and becomes a predetermined value or more, the safety valve mechanism opens, so the bypass passage is opened and the liquid refrigerant is opened. It is possible to cause a part of the high-pressure liquid refrigerant in the passage to flow into the gas refrigerant passage through the bypass passage to reduce the high-pressure pressure.

[0013]

1 is a longitudinal sectional view of a block type expansion valve according to an embodiment of the present invention. This is a conventional block type expansion valve incorporating a safety valve mechanism into a single unit. As shown in the figure, this safety valve mechanism incorporating block type expansion valve has a valve body 9 and an expansion valve mechanism 7 incorporated therein. , And a safety valve mechanism 8.

The valve body 9 has a liquid pipe connection port 91, an evaporator inlet connection port 92, an evaporator outlet connection port 93 and a gas pipe connection port 94, and a liquid passage 95 and a gas passage 96.
A bypass passage 97 is provided between and, and a seat surface 98 is provided at the opening of the bypass passage 97 on the gas passage 96 side. The configuration of the expansion valve mechanism 7 is the same as that of the conventional block type expansion valve 4 shown in FIG. 2, and the corresponding members are designated by the same reference numerals, and therefore the description of the configuration operation is omitted. The safety valve mechanism 8 is a packing 8 that closes the seat surface 98.
1, a valve rod 82, a cylindrical coil spring 83, and a holding plate 84.

In the safety valve mechanism 8, the valve rod 82 and the packing 81 have an upward force by the high pressure P ₁ in the liquid passage 95 and a downward force by the low pressure P ₂ in the gas passage 96 and a cylindrical coil spring. The restoring force of 83 acts.
Thus, the differential pressure ΔP between high pressure P ₁ and the low pressure P ₂ (=
When P ₁ -P ₂ ) becomes a predetermined value or more, the cylindrical coil spring 83
The valve rod 82 is pushed up to overcome the restoring force of the seat surface 9
8 opens. Then, one of the high-pressure liquid refrigerant in the liquid passage 95
Since the portion flows out to the gas passage 96 through the bypass passage 97, the high pressure can be reduced. In this embodiment, the block body of the block type expansion valve is provided with a bypass passage that connects and communicates the liquid refrigerant passage and the gas refrigerant passage, and the bypass passage has a high pressure P ₁ in the liquid refrigerant passage.
Differential pressure ΔP between the low pressure P ₂ of the gas coolant channel (= P ₁
-P ₂ ) is provided with a safety valve mechanism that opens when it exceeds a predetermined value, so high pressure P ₁ during the refrigeration cycle
When the pressure difference ΔP (= P ₁ −P ₂ ) between the low pressure P ₂ and the low pressure P ₂ rises above a predetermined value, the safety valve mechanism is opened, the bypass passage is opened, and the high pressure liquid refrigerant in the liquid refrigerant passage is opened. The high pressure can be reduced by letting the part flow out to the gas refrigerant passage through the bypass passage.

By installing the block type expansion valve incorporating the safety valve mechanism in the air conditioner, the following effects can be exhibited. (1) Refrigeration is not released to the outside of the refrigeration system like a conventional relief valve, so that re-charging of the refrigerant is not required at the time of reuse. Further, in the case of a car air conditioner, since the refrigerant and the lubricating oil do not flow out into the engine room as in the conventional case, white smoke and belt slip are not generated. (2) Since the bypass passage can be opened when the high-low pressure differential pressure ΔP rises, the compressor load at the time of starting the compressor or during operation can be reduced.

[0017]

According to the block type expansion valve of the present invention,
A bypass passage that connects the liquid refrigerant flow path and the gas refrigerant flow path is provided in the valve body, and the differential pressure ΔP (= P between the high pressure P ₁ in the liquid refrigerant flow path and the low pressure P ₂ in the gas refrigerant flow path). P ₁ −
Since the bypass valve is provided with the safety valve mechanism that opens when P ₂ ) becomes equal to or greater than the predetermined value, it is possible to reduce the abnormal increase in the high-pressure side pressure without discharging the refrigerant from the refrigeration cycle to the outside. . Further, in the air conditioner equipped with the block type expansion valve, it is possible to avoid interruption of use even when abnormal pressure rises.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a block type expansion valve according to an embodiment of the present invention.

FIG. 2 is a system diagram of a refrigeration cycle including a conventional block expansion valve, and a sectional view of the block expansion valve is shown.

FIG. 3 is a vertical sectional view of a conventional relief valve.

[Explanation of symbols]

 7 Expansion Valve Mechanism 8 Safety Valve Mechanism 9 Valve Body 42 Power Element 43 Temperature Sensitive Bar 43a Temperature Sensitive Part 44 Orifice 45 Ball 46 Cylindrical Coil Spring 47 Superheat Adjusting Screw 48 Diaphragm 49 Encapsulated Refrigerant 81 Packing 82 Valve Bar 83 Coil Spring 84 Presser Plate 91 Liquid Pipe Connection Port 92 Evaporator Inlet Connection Port 93 Evaporator Outlet Connection Port 94 Gas Pipe Connection Port 95 Liquid Passage 96 Gas Passage 97 Bypass Passage 98 Seat Surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Ishii 3-1, Asahimachi, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Air Conditioning Factory

Claims (2)

[Claims] 1. A valve body is provided with a liquid refrigerant channel and a gas refrigerant channel therein, and the evaporator outlet refrigerant temperature is sensed in the gas refrigerant channel to maintain the refrigerant superheat degree at the evaporator outlet at a set value. In the block type expansion valve whose flow rate is controlled as described above, a bypass passage that connects the liquid refrigerant flow path and the gas refrigerant flow path is provided in the valve body, and the high pressure P ₁ and the gas refrigerant in the liquid refrigerant flow path are provided. A block type expansion valve characterized in that a safety valve mechanism that opens when a pressure difference ΔP (= P ₁ -P ₂ ) from the low pressure P ₂ in the flow passage exceeds a predetermined value is provided in the bypass passage. . 2. An air conditioner equipped with the block type expansion valve with a safety valve mechanism according to claim 1.