JPS60128994A - Gas injection compressor - Google Patents

Abstract

PURPOSE:To insure a sufficient gas injection flow rate, while preventing pulsation of injection pressure, by connecting an intermediate part of a gas injection piping to a refrigerant storage chamber formed by an arm shaft bearing and a partition plate covering its perimeter. CONSTITUTION:Gas refrigerant separated from a gas-liquid separator 6 is introduced to a compressor 1 via an injection piping 7. The injection piping 7 extends through a enclosed vessel 8 and is connected to a refrigerant storage chamber 20 where the refrigerant is stored. Thus, the components of pressure-pulsation become little, a stable injection pressure is obtained, and the sufficient flow rate of gas-refrigerant can be insured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas injection compressor, and particularly to an improvement in a gas injection structure.

[Prior art]

FIG. 1 shows a conventional gas injection refrigeration cycle disclosed in, for example, Japanese Unexamined Patent Publication No. 104591/1982.
First capillary tube 4 and second capillary tube 5
A gas-liquid separator 6 is provided between the two, and the gas refrigerant separated by the gas-liquid separator 6 is injected into the compressor l via an injection pipe 7. Note that 2 is a condenser and 3 is an evaporator.

FIG. 2 is a Mollier diagram with pressure P on the vertical axis and enthalpy i on the horizontal axis. That is, the state of the refrigerant in a normal refrigeration cycle changes in the order of A-+B→C→D→A. On the other hand, in the gas injection refrigeration cycle, at point A, the same amount of refrigerant G as in a normal refrigeration cycle is sucked into the compressor l and compressed, and during the compression, the flow rate t is separated from the gas-liquid separator 6. only compressor
The refrigerant is injected into the cylinder, and at point B, the amount of refrigerant G+f is compressed and discharged. This discharged refrigerant is condensed in the condenser 2 and reaches point 0, and the refrigerant at point 0 is depressurized in the first capillary tube 4 and reaches point E, and enters the gas-liquid separator 6 in this state. The refrigerant at point E is separated into saturated liquid (liquid refrigerant) at point F and saturated vapor at point H in the gas-liquid separator 6. This separated gas refrigerant is directly injected into the cylinder of the compressor L by the injection pipe 7 at a flow rate t, and the remaining liquid refrigerant at point F (flow rate G) is introduced into the second capillary tube 5. The pressure is reduced to 1 point.

The liquid refrigerant at one point undergoes heat exchange in the evaporator 3, and is sucked into the compressor 1 again at point A. In the figure, Pd is the discharge pressure of the compressor 1, Pi is the injection pressure, and P8 is the compressor 1.
shows the suction pressure.

4 and 5 show a conventional gas injection compressor l, in which 8 is a closed container, 9 is an electric element, 10 is a compression element, and the compression element 10 is connected to a cylinder 11 and a crankshaft 13 integrated with an electric shaft. It has a compression chamber formed by a rolling piston 12 that is driven by the cylinder 11, an upper bearing 17 and a lower bearing 18 of a crankshaft 13 that seals the upper and lower parts of the cylinder 11, and the like. 14 is vane, 1
5 is a refrigerant suction hole provided in the peripheral wall of the cylinder 11;
Reference numeral 6 denotes an injection hole provided in the upper bearing 17, and an injection pipe 7 inserted through a closed container 8 is connected to the injection hole 16.

The rolling screw frame 1 is then driven by the electric element 9.
2 rotates, and the suction hole 15 and the injection hole 16
The refrigerant introduced through the compressor is compressed and discharged from a discharge hole (not shown).

By the way, the refrigeration capacity Q of the refrigeration cycle is generally determined by the following formula. That is, Q = (refrigerant flow rate in the evaporator) x (enthalpy difference between the inlet and outlet of the evaporator) Therefore, in a normal refrigeration cycle, the enthalpy of the refrigerant (point D) at the inlet of the evaporator 3 is 11% that of the outlet. Refrigerant (A
Since the enthalpy of point ) is t, its freezing capacity Qn
becomes Qn=G(it it). Also, in the injection refrigeration cycle, the enthalpy of the refrigerant at the inlet of the evaporator 3 (point 1) is io1, and the enthalpy of the refrigerant at the outlet (point A) is i.

The refrigerating capacity Qi is Qi=G(it 1o)=G((It-L)+(f+
1o)) Mi G (is il) + GΔi where Δi = f4− i.

becomes. Therefore, the refrigeration capacity QiO of the injection refrigeration cycle is higher than the refrigeration capacity Qn of the normal refrigeration cycle)
Qi increases by increasing GΔi and increasing the enthalpy difference Δi of the refrigerant at the inlet of the evaporator 3.

In order to increase Δi with
1 should be brought close to the suction pressure Ps of the compressor 1.

In Figure 3, the vertical axis shows the pressure P, and the horizontal axis shows the crank angle θ of the compressor 1.
It is a pressure diagram of the compression process in the compression chamber of the compressor 1 taken. In the figure, the shaded area indicates the range in which the compression chamber of the compressor 1 is injected. Here, it is set so that gas injection pressure Pi>compression chamber pressure P when gas injection circuit is closed. This is to prevent performance deterioration due to backflow from the compression chamber toward the gas-liquid separator 6. Therefore, in order to increase Δi in gas injection, the gas injection pressure Pi must be brought close to the suction pressure Ps of the compressor 1, and the crank angle θ for opening and closing the gas injection circuit must be made small.

However, when the difference in pressure between the injection pressure Pi and the pressure inside the compression chamber of the compressor I is small and the gas injection time is short, there is a drawback that a sufficient injection flow rate 2 cannot be ensured.

This occurs because the injection pressure Pi is affected by the pulsation of the discharge pressure Pd of the compressor 1, and the injection timing overlaps with the pulsating low pressure period. In addition, in order to flow a sufficient injection flow rate t in a short period of time, it is necessary to increase the diameter of the injection hole 16 to reduce the flow path resistance. There was a constraint that Furthermore, the compressor l
In order to obtain the optimum injection angle (time), it is necessary to open and close the injection hole 16 using the rolling piston 12 of the compressor 1. In this case, the injection pipe 7 is connected to the injection hole 16.
It is cheapest and easier to take out the outlet in the vertical direction connecting the center of the compressor l and the injection hole 16, but the upper bearing 17, lower bearing 18 and cylinder 11 that form the compression chamber are fixed The direction of extraction is restricted due to bolts and the like, and the extraction position of the injection pipe 7 may also be a problem when mounting a refrigeration system (unit).

[Summary of the invention]

The present invention has been made in consideration of the above-mentioned points, and includes a refrigerant storage chamber hermetically formed by an upper bearing 17 and a partition plate in the compressor l, and injection is carried out through this refrigerant storage chamber. By connecting the piping 7 and the injection hole 16, it is possible to reduce the pressure pulsation of the injection pressure Pi to ensure a sufficient injection flow rate t, and to take out the injection piping 7 from any direction in the circumferential direction of the compressor l. The purpose is to provide a gas injection compressor.

[Embodiments of the invention]

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

In FIG. 6, reference numeral 20 denotes a refrigerant storage chamber surrounded by the partition plate 19 and the upper bearing 17, and the injection hole 16 is also opened in the storage chamber 20. The gas refrigerant separated by the gas-liquid separator 6 is sent to the compressor 1 via an injection pipe 7.
guided by. The injection pipe 7 passes through the closed container 8 and is connected to the refrigerant storage chamber 20, so that the refrigerant is stored in the storage chamber 20. As a result, the pressure pulsation component is reduced, a stable injection pressure Pi is obtained, and a sufficient injection flow rate t of the gas refrigerant can be secured, and this gas refrigerant is injected into the cylinder 11 through the injection hole 16. Injected. In addition, injection piping 7
The connection between the airtight container l and the refrigerant storage chamber 20 is performed by brazing and press fitting to prevent refrigerant leakage.

In the above embodiment, by providing the refrigerant storage chamber 20, the injection/pressure Pi can be softened from pressure fluctuations due to pressure pulsations in the discharge pressure Pd of the compressor 1, and a nearly constant pressure can be obtained, and a sufficient injection flow rate can be obtained. can get. or,
The direction in which the injection pipe 7 is taken out can be freely selected since it is not obstructed by bolts for mounting the upper bearing 17.

FIG. 7 shows a second embodiment of the present invention. In this embodiment, a refrigerant storage chamber 20 is provided as in the previous embodiment, and the lower bearing 18 is covered with a partition plate 19a to form a refrigerant storage chamber 20a. An injection hole 1 is formed in the lower bearing 1B and communicates between the inside of the cylinder 11 and the refrigerant storage chamber 20a.
6a is provided, and the refrigerant storage chamber 20.20a is provided with bearings 17, 18.
and communicate through a communication hole 21 provided in the cylinder 11.

In this case, the gas refrigerant passes through the injection pipe 7 from the gas-liquid separator 6, flows into the cylinder 11 through the storage chamber 20 and the injection hole 16i, and also flows into the cylinder 11 through the communication hole 211, the storage chamber 20a, and the injection hole 16a.
It enters the cylinder ll through. In this way, the gas refrigerant flows into the cylinder 11 through the two injection holes 16.16a, so that the flow path resistance is reduced and a sufficient amount of injection can be obtained.

〔Effect of the invention〕

As described above, in the present invention, since the injection pipe and the injection hole are connected through the refrigerant storage chamber, the pulsation of the injection pressure is reduced, and a sufficient injection flow rate can be obtained to perform good injection. can. Furthermore, the injection pipe can be connected to the refrigerant storage chamber from any direction without any problem. Furthermore, by allowing the refrigerant to flow into the compression chamber through the two injection holes, the flow resistance of the refrigerant can be reduced, and a sufficient injection flow rate can also be obtained thereby.

[Brief explanation of the drawing]

Figures 1 and 2 are respectively a conventional gas injection refrigerant circuit diagram and its Mollier diagram, Figure 3 is a characteristic diagram of the pressure change in the compression chamber due to the rotation of the piston during the compression process of the compressor, and Figures 4 and 2 are 5 is a longitudinal sectional front view and an X-X cross-sectional plan view thereof of a conventional gas injection compressor, respectively, and FIG. 6 is a longitudinal sectional front view of a gas injection compressor O according to the first embodiment of the present invention. FIG. 7 is a longitudinal sectional front view of a gas injection compressor according to a second embodiment of the present invention. l... Compressor, 6... Gas-liquid separator, 7... Injection piping, 8... Sealed container, 9... Electric element, IO... Compression element, 11... Cylinder, 12...
・Rolling piston, 13...crankshaft,
16.16g...Injection hole, 17...Upper bearing, 18...Lower bearing, 19.19a...Partition plate,
20.20&--refrigerant storage chamber. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 i! Continuation of iT, Q figure 3 figure 1 page [phase] Inventor Kazutomo Asami Oshika h, Shizuoka city

Claims (2)

[Claims] (1) Compression having a compression chamber consisting of a rolling piston driven via the crankshaft, a cylinder housing the rolling piston, and an upper and lower bearing that seals the upper and lower parts of the cylinder and supports the crankshaft. element and crankshaft ↑ In a gas injection compressor where the driving electric element is housed in a sealed container and is connected to the injection piping for injecting the gas refrigerant separated by the gas-liquid separator of the gas injection refrigerant circuit, the injection piping is connected to a refrigerant storage chamber formed by an upper bearing and a partition plate surrounding the upper bearing, and the refrigerant storage chamber and compression chamber are communicated through an injection hole provided in the upper bearing. 1゜ (2) Compression having a compression chamber consisting of a rolling piston driven via the crankshaft, a cylinder housing the rolling piston, and an upper and lower bearing that seals the upper and lower parts of the cylinder and supports the crankshaft. In a gas injection compression machine, the electric element that drives the element and the crankshaft are housed in a sealed container, and an injection pipe for injecting gas refrigerant is connected to the gas injection refrigerant circuit, which is separated by a gas-liquid separator. The injection pipe is connected to a refrigerant storage chamber formed by an upper bearing and a partition plate surrounding the upper bearing, and the refrigerant storage chamber and the compression chamber are communicated through an injection hole provided in the upper bearing.
A second refrigerant storage chamber is formed by the lower bearing and a second partition plate surrounding the lower bearing, and each refrigerant storage chamber is communicated with each other through communication holes provided in the cylinder and the upper and lower bearings. A gas injection compressor, characterized in that a second injection hole is provided in the lower bearing to communicate with the compression chamber.