JPH06213160A - Reciprocating refrigerating compressor - Google Patents

Abstract

PURPOSE:To prevent the reduction of the refrigerating capability by performing the necessary cooling via the injection of a liquid refrigerant only during the compression stroke in a reciprocating compressor. CONSTITUTION:A reciprocating refrigerating compressor is provided with a piston 6 reciprocated in a cylinder 5, an intake valve 3, a delivery valve 7, an injection passage 12 guiding a liquid refrigerant into the cylinder 5 from the outside, and a plunger valve 11 directly communicating the injection passage 12 with the cylinder interior 4 of the cylinder 5, operated by the pressure difference with the cylinder internal pressure at the time of the intake stroke to close the injection passage 12, and operated by the pressure difference with the cylinder internal pressure at the time of the compression stroke to open the injection passage 12. The liquid refrigerant is injected into the cylinder interior 4 for cooling only during the compression stroke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating type refrigerating compressor capable of performing necessary cooling and preventing deterioration of refrigerating capacity.

[0002]

2. Description of the Related Art In a conventional reciprocating type refrigerating compressor for sucking a refrigerant gas into a cylinder for compression by reciprocating a piston, a refrigerant introduced from an external evaporator (not shown) is generally shown in FIG. The gas is compressed by a piston 6 in a cylinder 4 surrounded by a cylinder 5 and a piston 6 via a suction chamber 1, a valve plate suction port 2 and a suction valve 3 and then discharged from a discharge chamber 8 via a discharge valve 7. It is discharged to a condenser (not shown). Further, in the operation with a high compression ratio, liquid injection of the liquid refrigerant is performed from the outside via the plug 1a provided in the suction chamber 1 for cooling the cylinder.

[0003]

In the above-mentioned conventional reciprocating compressor, when operating at a high compression ratio, the temperature of the cylinder 4 and the temperature of the discharge chamber 8 rise, and the scuff on the surface of the cylinder 5 and the discharge valve. Problems such as oil carbonization around 7 occur.
In order to avoid this, as described above, the high pressure liquid refrigerant return circuit is provided in the suction pipe or the suction chamber to measure the cooling. However, this method has a drawback that the refrigerating capacity of the liquid amount returned by so-called liquid bypass is reduced.

An object of the present invention is to provide a reciprocating refrigeration compressor capable of cooling a cylinder or the like and operating at a high compression ratio without lowering the refrigerating capacity.

[0005]

According to the present invention, there is provided a cylinder, a piston reciprocating in the cylinder, a suction valve and a discharge valve, and a reciprocating liquid injection passage for guiding a liquid refrigerant from the outside into the cylinder. In a dynamic refrigeration compressor, the liquid injection passage is directly communicated with the inside of the cylinder, and the passage is closed due to the pressure difference between the liquid injection passage and the cylinder internal pressure during the suction process. It is characterized by installing a plunger valve that operates by the pressure difference from the internal pressure and opens the same passage.

[0006]

In the present invention, the plunger valve operates due to the pressure difference from the pressure in the cylinder during the suction process, closes the injection passage for introducing the liquid refrigerant into the cylinder, and operates due to the pressure difference between the inside of the cylinder during the compression process. To open the injection passage. With this plunger valve, the liquid refrigerant is injected into the cylinder through the injection passage only in the compression process in which the suction valve is closed, and the necessary cooling action is performed. In addition, since the liquid refrigerant is not injected in the suction process, the amount of suction gas in the suction process does not decrease, and the volume effect (refrigerating capacity) is prevented from decreasing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the reciprocating compressor has a suction chamber 1, a valve plate suction port 2, a suction valve 3, a cylinder 5, a piston 6, a discharge valve 7 and a chamber as in the conventional compressor shown in FIG. Eight.

A plunger hole 10 is provided in the cylinder 5 in the vertical direction, and an upper end of the plunger hole 10 is inserted through a pressure guide hole 9 provided in the cylinder 5 into the cylinder cylinder 4
And a lower end thereof is connected to a crank case (not shown) through a pressure guide hole 13 provided in the cylinder 5. Further, in the plunger hole 10, a plunger 11 having a central portion having a small diameter and having a liquid flow path 11a formed therein is housed so as to be capable of reciprocating in the vertical direction. The plunger 11 having the same liquid flow path 11a constitutes a valve, and the injection passage 12 of the liquid refrigerant that penetrates the cylinder 5 from the outside and opens in the cylinder 4 is opened and closed. 1
Reference numeral 4 denotes a plug provided at the outer end of the injection passage 12.

In this embodiment, in the step of inhaling the piston 6, the inhalation gas enters the cylinder 4 by opening the inhalation valve 3 through the inhalation chamber 1 and the valve plate inhalation port 2. At this time, the pressure in the cylinder 4 is applied to the upper part of the plunger 11 via the pressure guiding hole 9, but this pressure is lower than the crankcase pressure applied to the lower part of the plunger 11 via the pressure guiding hole 13, so as shown in FIG. , The plunger 11 is pulled upward, and the injection passage 12 is closed.

In the compression process of the piston 6, the cylinder pressure 4
The pressure at the upper part of the plunger 11 becomes higher than the pressure at the lower part of the plunger 11 during the compression when the pressure rises and becomes higher than the crankcase pressure, and due to the pressure difference between the upper and lower parts of the plunger 11, as shown in FIG. , The plunger 11 is pulled down, and the injection passage 12 is opened via the liquid flow passage 11a. As a result, a high-pressure (including intermediate pressure) liquid refrigerant is injected from the outside into the cylinder 4 via the plug 14.

In the present embodiment, as described above, the injection of the liquid refrigerant is not performed during the intake process of the piston 6 (when the intake valve is open), but the injection of the liquid refrigerant is performed during the compression process (when the intake valve is closed). By this, there is no decrease in the amount of suction gas during the suction process, and there is no reduction in volume efficiency.
Further, in the compression step, the injection of the liquid refrigerant is continued until the in-cylinder pressure reaches the injection pressure of the liquid refrigerant, and the necessary cooling action can be performed.

The end time of the injection of the liquid refrigerant is determined by selecting the time when the land portion above the piston 6 closes the injection passage 12, and the end time of the injection of the liquid refrigerant can be set appropriately. .

[0013]

According to the present invention, the injection passage directly communicating with the inside of the cylinder is actuated by the difference in force between the injection passage and the pressure inside the cylinder during the suction stroke to close the passage, and the pressure within the cylinder during the compression stroke is used. Since the plunger valve that operates to open the passage opens and closes, it is possible to inject the liquid refrigerant after the suction valve is closed in the compression process, and avoid a decrease in volumetric efficiency (refrigeration capacity). It is possible to cool the cylinder to a predetermined level, which has the effect of increasing the reliability of the compressor in high compression ratio operation and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory view showing a state in which an injection passage is opened by the plunger valve of the same embodiment.

FIG. 3 is a sectional view of a conventional reciprocating compressor.

[Explanation of symbols]

 1 suction chamber 1a plug 2 valve plate suction port 3 suction valve 4 in-cylinder 5 cylinder 6 piston 7 discharge valve 8 discharge chamber 9 pressure guide hole 10 plunger hole 11 plunger 11a liquid flow path 12 injection passage 13 pressure guide hole 14 plug

Claims (1)

[Claims] 1. A reciprocating refrigeration compressor comprising a cylinder, a piston reciprocating in the cylinder, an intake valve and a discharge valve, and a liquid injection passage for guiding a liquid refrigerant from the outside in the cylinder. The liquid injection passage is directly connected to the inside of the cylinder, and the passage is closed due to the pressure difference from the pressure inside the cylinder during the suction process to close the passage and the pressure difference from the cylinder pressure during the compression process. A reciprocating refrigeration compressor, which is equipped with a plunger valve that opens the same passage.