JPH0243019Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liquid refrigerant throttle valve for a refrigeration compressor.

Conventionally, for example, a refrigeration compressor having a structure shown in FIG. 1 has been used. 1 in the figure is the compressor main body.
A discharge pipe 2 for discharging refrigerant inside the compressor body 1 is led out to the outside. In the discharge pipe 2,
A condenser 4, a constrictor 5, an evaporator 6, and an accumulator 7 are connected by a refrigerant supply pipe 3,
The accumulator 7 communicates with the inside of the compressor body 1 through a suction pipe 8 . The accumulator 7 separates the refrigerant supplied from the evaporator 6 into a liquid refrigerant 9 and a gas refrigerant 10, stores the liquid refrigerant 9 in the accumulator 7, and supplies only the gas refrigerant 10 into the compressor body 1. . Inside the compressor body 1, a motor 1 is installed.
The compressor is operated by the rotation of a crankshaft 12 which is rotated by the drive of this motor 11, and the gas refrigerant 10 sucked through the suction pipe 8 is compressed. The compressed gas refrigerant 10 is discharged into the discharge cavity 13 at the lower end of the compressor main body 1 through a discharge valve (not shown), then led out into the space 14, passed around the motor 11, and compressed from the discharge pipe 2. It is designed to be discharged to the outside of the machine body 1. In addition, 15 in the figure is
This is lubricating oil stored in the lower part of the compressor body 1.

However, in the refrigeration compressor 16 configured in this way, especially when a rotary compressor is adopted, the liquid refrigerant 9 accumulated in the evaporator 6 when the operation is stopped is
However, the liquid refrigerant 9 that flows into the accumulator 7 all at once during restart, or that has not been completely evaporated in the evaporator 6 during light load, continuously flows into the accumulator 7. Therefore, the liquid refrigerant 9 exceeds the allowable liquid amount of the accumulator 7 and is sucked into the compressor main body 1 through the suction pipe 8. As a result, liquid compression occurs within the compressor main body 1, causing problems such as damage to the valve portion or abnormal increase in compression torque, which causes the compressor to stop driving.

To solve this problem, the accumulator 7
It is conceivable to increase the internal volume of the accumulator 7 to increase the permissible liquid amount of the accumulator 7, but this has the disadvantage of increasing the price and occupying a large space. It goes without saying that such a problem also occurs in the case of a reciprocating compressor.

This invention was made in view of these points,
By preventing the suction of liquid refrigerant into the compressor body and preventing the liquid compressor phenomenon, the life of the refrigeration compressor can be extended and stable operation can be achieved.
Furthermore, it is possible to provide an inexpensive liquid refrigerant throttle valve for a refrigeration compressor.

That is, the present invention is a liquid refrigerant throttle valve provided in a suction pipe of a refrigeration compressor, which is biased in the opposite direction of refrigerant flow through a spring in a case to which refrigerant pipes are connected at both ends. Has a communication hole for refrigerant throttling,
A liquid refrigerant throttle valve for a refrigeration compressor, characterized in that it is provided with a valve body that is actuated by a pressure difference after the communication hole due to the difference in specific gravity of whether the refrigerant passing through the communication hole is liquid or gas, and restricts the flow of liquid refrigerant. It is.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a partially cutaway view of one embodiment of the present invention. In the figure, 20 is a compressor main body that constitutes a rotary compressor. A discharge pipe 21 for discharging the refrigerant inside the compressor body 20 is led out to the outside. A condenser 23 , a constrictor 24 , an evaporator 25 , and an accumulator 26 are sequentially connected to the discharge pipe 21 via a refrigerant supply pipe 22 . Evaporator 25
In the refrigerant supply pipe 22 between the and the accumulator 26,
A liquid refrigerant throttle valve 27 is attached. The accumulator 26 separates the refrigerant supplied from the evaporator 25 into a liquid refrigerant 28 and a gas refrigerant 29.
It has a function of storing gas refrigerant 29 in the accumulator 26 and supplying only the gas refrigerant 29 into the compressor main body 20, and communicates with the compressor main body 20 via the suction pipe 30. As shown in FIG. 3A, the liquid refrigerant throttle valve 27 includes a substantially cylindrical case 27a into which a refrigerant supply pipe 22a on the evaporator 25 side is inserted, and this case 2.
It has a valve seat 27b fitted so as to close the opening on the accumulator 26 side of 7a. Valve seat 27
In b, the refrigerant supply pipe 22 on the side of the accumulator 26 is shown.
One end of b is inserted. Inside the case 27a, a valve body 27e has a protrusion 27d that fits into the open end of the refrigerant supply pipe 22b that communicates with the case 27a through a communication hole 27c formed in the valve seat 27b.
is slidably housed via a spring 27f. The valve body 27e includes the evaporator 25 of the case 27a.
An upstream chamber 27g formed by the inner wall surface of the side and the valve body 27e, and a downstream chamber 2 formed by the inner wall surface of the case 27a on the accumulator 26 side and the valve body 27e.
A communication hole 27i is provided to communicate with 7h.

Further, a motor 31 is built inside the compressor main body 20. The compressor is operated by the rotation of the crankshaft 32 which is rotated by the drive of the motor 31, and the gas refrigerant 2 sucked from the suction pipe 30 is
9 is now compressed. The compressed gas refrigerant 29 is discharged into the discharge cavity 34 at the lower end of the compressor main body 20 through a discharge valve (not shown), and then guided into the space 33 and passed around the motor 31 to be compressed from the discharge pipe 21. It is designed to be discharged to the outside of the machine body 20. In addition, 33 in the figure
is lubricating oil stored in the lower part of the compressor main body 20.

Thus, the refrigeration compressor 40 configured in this way
According to the above, by providing a liquid refrigerant throttle valve 27 between the evaporator 25 and the accumulator 26, the liquid refrigerant 28 entering the accumulator 26 is
The amount of liquid can always be set below the allowable liquid amount. That is, the pressures in the upstream chamber 27g and downstream chamber 27h of the liquid refrigerant throttle valve 27 shown in FIG. 3A are respectively P ₁ ,
Assuming P ₂ , the pressure difference (ΔP=P ₁ −P ₂ ) can be expressed by the following equation.

ΔP=ζγ/2gυ ² () Here, ζ is the pressure loss coefficient, γ is the specific weight of the fluid, υ is the flux, and g is the gravitational acceleration. This pressure difference ΔP causes the valve body 27e to move into the upstream chamber 27g.
A force F is generated to push the air out to the downstream chamber 27h, and this force F is expressed by the following equation.

F=A·ΔP () Here, A is the pressure receiving area of the valve body 27e.
This force F is proportional to the specific weight γ of the fluid, but the specific weight of the liquid refrigerant 28 is several tens of times larger than the specific weight of the gas refrigerant 29, so the force F when the liquid refrigerant 28 flows is several tens of times larger than in the case of gas refrigerant 29. If the spring force of the spring 27f is appropriately selected, when the gas refrigerant 29 flows, the valve body 27e is pressed toward the upstream chamber 27g as shown in FIG. As shown in FIG. 2, the valve body 27e moves toward the downstream chamber 27h against the spring force, and stops at a position where the spring force and the differential pressure F are balanced. In other words, when the gas refrigerant 29 flows from the evaporator 25, the valve body 27e is pushed to the left as shown in FIG. 3A, so the passage between the valve body 27e and the valve seat 27b is large. The gas refrigerant 29 is not limited in any way,
flows. Further, since the specific weight of the gas refrigerant 29 is small, the pressure loss (differential pressure ΔP) when flowing through the communication hole 27i is also small, and the effect on the performance of the compressor main body 20 is also small.

When the flow from the evaporator 25 is the liquid refrigerant 28, the valve body 27e moves toward the downstream chamber 27h as shown in FIG. 28 is constricted to restrict flow. (If necessary, the valve body 27e and the valve seat 2
7b passage may be closed). Therefore, the amount of liquid refrigerant 28 flowing through the liquid refrigerant throttle valve 27 to the accumulator 26 is small, and the amount of liquid refrigerant 28 flowing through the accumulator 26 is small.
Operation can be continued without exceeding the allowable liquid volume.

In addition to the liquid refrigerant throttle valve 27 used in the embodiment, as shown in FIG.
A liquid refrigerant throttle valve 42 may be used that allows part of the liquid refrigerant 28 to flow toward the accumulator 26 through a bleed board 41 formed on the valve seat 27b. In the figure, the same parts as the liquid refrigerant throttle valve 27 of the embodiment are designated by the same reference numerals.

Further, the liquid refrigerant throttle valve 27 may be installed at a location other than the refrigerant supply pipe 22 between the evaporator 25 and the accumulator 26 as long as it is between the evaporator 25 and the compressor main body 20. When the compressor body constitutes a reciprocating compressor, it may be installed inside the compressor body.

As explained above, according to the liquid refrigerant throttle valve for a refrigeration compressor according to the present invention, the life of the refrigeration compressor can be extended by preventing liquid refrigerant from being sucked into the compressor body and preventing the liquid compression phenomenon. It also has remarkable effects such as stable driving and low cost.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway view of a conventional refrigeration compressor, Fig. 2 is a partially cutaway view of an embodiment of the present invention, and Figs. 3A and 3B are used in the same embodiment. A sectional view of a liquid refrigerant throttle valve. FIG. 4 is a sectional view of another embodiment of a liquid refrigerant throttle valve. 20...Compressor main body, 21...Discharge pipe, 22...
... Refrigerant supply pipe, 23 ... Condenser, 24 ... Throttle, 25 ... Evaporator, 26 ... Accumulator,
27...Liquid refrigerant throttle valve, 28...Liquid refrigerant, 29...
...Gas refrigerant, 30...Suction pipe, 31...Motor,
32...Crankshaft, 33...Space, 4
0... Refrigeration compressor, 27a... Case, 27b...
...Valve seat, 27c...Communication hole, 27d...Protrusion,
27e... Valve body, 27f... Spring, 27g... Upstream chamber, 27h... Downstream chamber, 27i... Communication hole.

Claims (1)

[Scope of utility model registration request] A liquid refrigerant throttle valve installed in the suction pipe of a refrigeration compressor, which is biased in the opposite refrigerant flow direction via a spring in a case with refrigerant pipes connected to both ends, and has a communication hole for refrigerant throttling. for a refrigeration compressor, characterized in that the valve body is actuated by a pressure difference after the communication hole due to the difference in specific gravity of whether the refrigerant passing through the communication hole is liquid or gas, and restricts the flow of liquid refrigerant. Liquid refrigerant throttle valve.