JPH02140479A - Capacity control device for gas compressor - Google Patents

Abstract

PURPOSE:To enable minute control by supplying and discharging a noncompressible fluid into a space between an unloader piston and an unloader cylinder on the opposite side to the communicating side of the unloader piston with a gas compression space. CONSTITUTION:A vertically movable unloader piston 1 is inserted inside an unloader cylinder 17, and the top clearance volume 4 changes accordingly. A passage is formed of a high pressure oil pipe 23 side or a crank case oil pipe 24 side and the inlet/outlet port 22 of controlling oil by a three-way control valve 3. Both passages can be also closed. The vertical position of the unloader piston 1 can be optionally selected only by the control of the supply/discharge quantity of the operating oil into a space 2, and if the position is once selected, the controlling oil is invariable to the rise of a piston 5 because of its noncompressibility, the top clearance volume 4 is also set inevitably, and thereby the volume control as a compressor can be achieved. The stepless volume control of the compressor can be thus obtained so as to enable minute control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capacity control device applied to a positive displacement gas compressor.

[Prior Art] As a conventional example of a capacity control device that controls the discharge amount of a compressor by changing the volume of a compression chamber, a reciprocating compressor is used.
FIG. 14 shows the main parts of JP-A-62-12880.

In the figure, by applying discharge gas pressure or suction gas pressure to the space 2 above the unloader piston 1 through the three-way switching valve 3, the unloader piston 1 is moved to the lower end or the upper end, and the piston 5 is moved to the upper end. Compression chamber 12 at point
It was designed to change the volume in two stages.

The volume of the compression chamber 12 when the piston 5 is at the top dead center is called the top clearance volume.When the top clearance volume 4 is large (when the unloader piston 1 is at the top end), the discharge gas flow rate is small; is small (unloader piston 1
(at the lower end), the discharge gas flow rate is maximum.

As shown in the figure, gaskets 6 and 7 are fitted near the upper and lower ends of the unloader piston l to maintain airtightness.

[Problem to be solved by the invention]

The conventional capacity control device using gas pressure has the following problems to be solved.

(1) The unloader piston l can only be controlled in two stages, making fine control impossible.

(2) In a multi-cylinder compressor using the above-mentioned unloader piston control device, when performing capacity control in multiple stages, only the gas body whose volume fluctuates is used for control, which has the disadvantage of large torque fluctuations and large vibrations. Ta. Furthermore, control became complicated and costs increased.

(3) In order to reduce the leakage of the discharge gas or suction gas loaded above the unloader piston 1 and prevent a decrease in efficiency, it is not recommended to use Punkin 6, 7, etc. in the unloader piston 1 part. The structure became complicated and the cost increased.

[Means to solve the problem]

The present invention provides the following (1) to (4) as means for solving the above problems.
The present invention aims to provide a capacity control device for a compressor as shown in Section 1.

(1) In a capacity control device for a reciprocating gas compressor,
A capacity control device for a gas compressor, comprising a control mechanism that changes the top clearance volume steplessly or almost steplessly.

(2) In a capacity control device for a gas pressure machine comprising a top clearance volume for capacity control communicating with a compression chamber, the top clearance volume is shaped like a cylinder, and the unloader piston is slidably sealed in the cylinder. At the same time as fitting, is the pressure restricted only in the cylinder space on the side opposite to the compression chamber of the unloader piston? 1. A capacity control device for a gas compressor, comprising control means for steplessly controlling the position of the unloader piston.

(3) A capacity control device for a gas compressor that controls the capacity of the compressor by changing the volume of the gas compression chamber by causing an unloader piston in an unloader cylinder that communicates with the gas compression chamber to hyper-move, wherein the unloader piston The gas compression chamber is characterized by comprising a control means for controlling the position of the unloader piston by supplying and discharging incompressible fluid to a space between the gas compression chamber and the unloader cylinder on the opposite side from the side communicating with the gas compression chamber. Machine capacity control device.

(4) In a gas compressor capacity control device that controls the capacity of a compressor by changing the volume of a gas compression chamber by moving an unloader piston in an unloader cylinder that communicates with the gas compression chamber, the An electromagnetic switching valve that supplies, discharges, or closes incompressible fluid to the space between the unloader cylinder and the unloader cylinder on the opposite side from the side that communicates with the gas compression chamber, and the control amount of the controlled object that is higher than the two set values or and a control means for controlling the electromagnetic switching valve by selectively selecting one of two power supplies that are intermittently turned on and off when the temperature is low. Device.

[Effect]

Since the present invention is configured as described above, it has the following effects.

(1) In the configuration of item (1) above, the top clearance volume can be adjusted steplessly or! ``Since it is equipped with a stepless variable control mechanism (4B), fine capacity control is possible.

(2) In the configuration described in item (2) above, the top clearance volume is in the shape of a cylinder, the unloader piston is fitted in a sealed and slidable manner within the cylinder shape, and the cylinder space on the side opposite to the compression chamber of the piston is provided. Since the unloader piston is provided with means for controlling the position of the unloader piston by controlling the pressure in the cylinder, stepless displacement control is possible by steplessly controlling the pressure in the cylinder space.

(3) In the configuration described in item (3) above, unlike in the past, an incompressible fluid such as oil is supplied and discharged into the space between the unloader cylinder and the unloader piston to control the position of the unloader piston (therefore, the compression Since the capacity of the compressor is controlled 'a), it is possible to control the capacity of the compressor steplessly by controlling the flow rate of the incompressible fluid only.

In addition, since the unloader piston is free, the pressure on the side of the unloader piston that communicates with the gas compression chamber is immediately transmitted to the incompressible fluid on the opposite side, reducing the pressure difference between the two sides (top and bottom) of the unloader piston. Therefore, harmful leakage can be eliminated without using a puncture on the unloader piston.

In addition, in the case of a multi-cylinder compressor, by connecting the space between the unloader piston of each cylinder and the unloader cylinder through a throttle, the unloader piston of each cylinder has the same capacity control rate for the cylinders during operation. The average pressure in the compression chamber (considered as an effective value) is closely related to the top clearance volume, and the smaller the top clearance volume, the higher it will be, and the incompressible fluid pressure in the space between the unloader piston and unloader cylinder also increases. (As mentioned above, the unloader piston of each cylinder moves uniformly due to incompressible fluid control.) As a result, torque fluctuation, vibration, and noise are low, resulting in high efficiency.

(4) In the configuration described in item (4) above, the electromagnetic switching valve is operated intermittently, and the unloader piston is displaced during the opening time of the electromagnetic switching valve, thereby changing the compressor capacity. This process controls the compressor displacement and, during the closing time, controls the movement of the unloader piston by controlling the compressor displacement to a fixed state.

〔Example〕

A first embodiment of the present invention will be described with reference to FIG. Components similar to those in FIG. 14 are given the same reference numerals, and explanations will be omitted unless necessary.

FIG. 1 shows an example in which a capacity control device according to an embodiment of the present invention is applied to a reciprocating refrigeration pressure machine. In the figure, a piston 5 reciprocates up and down within a cylinder case 8. When the piston 5 goes down, the refrigerant gas passes through the suction chamber 9, the suction passage 10, and the suction valve 11, and then enters the compression chamber 12. When the piston 5 goes up, the gas in the compression chamber 12 is compressed, and the discharge valve 13 is opened, and the refrigerant gas passes through the discharge passage 14. It is discharged into the discharge chamber 15.

A capacity control device described below is installed in the reciprocating refrigeration pressure 1i1 machine that performs the suction and compression action of refrigerant gas as described above.

An unloader cylinder 17 is fixed to the center of the cylinder of the valve plate 16 with bolts 25.

An unloader piston 1 is inserted into the unloader cylinder 17 and can move up and down, thereby changing the top clearance volume 4.

At the bottom of the unloader cylinder 17 is a discharge valve inner valve seat 1.
8 is fixed with screws, Loctite, etc.

A cover 19 is attached to the top of the unloader cylinder 17 with bolts 20.
Fixed by

The concave portion of the lid 19 and the convex portion of the unloader piston 1 can be fitted with a narrow gap between them, thereby preventing the unloader piston 1 from violently colliding with the lid 19.

A space 2 above the unloader piston 1 is connected to a control oil inlet/outlet 22 through a hitting pipe 21 and the like.

A high-pressure oil pipe 2 connected to high-pressure oil by a three-way control valve 3
The third side or the crankcase oil pipe 24 side connected to the crankcase side and the control oil inlet/outlet 22 can form a passage. Also, both passages are constructed so that they can be closed.

With this structure, the vertical position of the unloader piston 1 can be arbitrarily selected by simply controlling the amount of control oil supplied into the space 2, and once the position is selected, the control oil is stopped. Since it is compressible, it remains unchanged even when the piston 5 rises, and the top clearance volume 4 is also inevitably determined, achieving capacity control as a compressor.

Next, as a second embodiment of the present invention, an example of a multi-cylinder compressor will be explained with reference to FIG. Note that the individual configuration of each compressor is the same as in the first embodiment.

In the figure, if the control oil inlet/outlet 22 of each cylinder is connected to the three-way control valve 3 through a restriction such as a capillary tube 25 or 26 as shown in the figure, the unloader piston 1 of each cylinder is Since they are controlled by compressible control oil, they move in the same way all at once.

Therefore, capacity control similar to that in the first embodiment can be performed equally on each cylinder, and torque fluctuations, vibrations, etc. will not occur.

Incidentally, the high pressure oil used as control oil is the oil in the oil separator attached to the discharge gas system (not shown),
Alternatively, it can be obtained using a hydraulic pump or the like. The oil separator can also be installed within the discharge chamber 15.

Next, a third embodiment of the present invention will be described with reference to FIGS. 3 to 5. 4 is similar to FIG. 1 except for specifically explained members, and is designated by the same reference numerals.

The circuit 31 within the dotted line in FIG. 3 controls the position of the unloader piston 1 shown in FIG. 4 by means of temperature-activated switches SL and S2, which control the position of the unloader piston 1 shown in FIG. 5.
This is a control circuit that operates Z intermittently. The electromagnetic switching valve 30 in Fig. 4 is replaced with the electromagnetic valve sv,, sv shown in Fig. 5.
If configured with a combination of 2 operations, all operations are the same.When the control oil temperature rises after the compressor starts, TH
The contacts close and electricity is supplied. Furthermore, 32 to 37
is a terminal for supplying power to the circuit. The switch s1 is a temperature switch that closes when the temperature inside the refrigerator is above a first set value and opens when it is less than the first set value, and the operation of the switch s1 is transmitted to the auxiliary relay-4. When the auxiliary relay steel is energized, its contacts "l'+III+" are closed, and the intermittent timer T1 is activated, and its contacts T,
r repeats opening and closing, auxiliary relay closes, second contact m
, " is transmitted to the solenoid valve Sv1. That is, when the switch s1 is closed, the solenoid valve SV repeats opening and closing. The opening and closing times of the solenoid valve Sv1 can be set arbitrarily by a timer T, respectively.

Switch S2 is a temperature switch that closes when the temperature inside the refrigerator is below a second set value and opens when it exceeds the second set value.
The operation is transmitted to auxiliary relay l112.

When auxiliary relay I11 is energized, its contacts m, l,
m2# is closed, the intermittent timer TI is activated, its contacts T and r repeat opening and closing, and the auxiliary relay m2
is transmitted to the solenoid valve sv2 via the second contacts m and # of.

That is, when the switch S2 is closed, the solenoid valve SVz repeats opening and closing.

Here, the first set value of the internal temperature is set to a higher temperature than the second set value.

The solenoid valves SVw and SVz are used as control valves to control the position of the unloader piston 1 and to control the capacity of the compressor by supplying and discharging incompressible fluid. When Sv2 is opened, the unloader piston 1 is raised and the capacity of the compressor is decreased.

When the temperature inside the refrigerator is within the first and second set values, the switch Sl
, S2 are both OFF, solenoid valves SV+ and SVz are both closed, allowing the flow of control oil to rise and fixing the unloader piston.

With this configuration, after the control oil temperature rises,
When the internal temperature rises, the pressure increases to 1i! When the capacity (capacity) of the compressor increases and the temperature inside the refrigerator decreases, the capacity (capacity) of the compressor decreases, so the temperature inside the refrigerator can be controlled within a concave set range.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Components similar to those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted unless necessary.

Figure 6 shows an example in which different types of sensors are installed, where s3 is connected to the power supply and switch sl when the current is less than the upper limit set value of the compressor motor, and when it is above it, the terminal 34 is connected to the power supply. It is a current switch for.

The third embodiment is the same as the third embodiment except that the current switch S3 is incorporated.

With this configuration, when the temperature inside the refrigerator is high and the compressor is in overload operation, the current switch S3 detects the overload current, activates the auxiliary relay m, and opens the solenoid valve Sv to unload the compressor. The capacity of the compressor can be controlled so that the piston 1 is raised and the motor current is below the upper limit value. When the motor current is below the upper limit, control is performed in the same manner as in FIG. 3.

The above is the switch sl of FIG. 3 used in the third embodiment.

Although S2 is a temperature-operated switch, it is not limited to a temperature switch; for example, a (suction) pressure sensor may be used instead, and switches and sensors for credit banking purposes may be used.

Further, the current switch shown in FIG. 6 used in the fourth embodiment may be replaced with, for example, a (suction) pressure switch of the compressor.

Further, the TI contacts in FIGS. 3 and 6 may be replaced by timer contacts whose set value is the time for the temperature of the compressor to rise after operation, or may be replaced by other appropriate means. .

In both the third and fourth embodiments, the first set value and the second set value were set separately, but they are integrated into one set value, and two different set values are created inside the control device. is also free.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. 7 and 8.

Components similar to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted unless necessary.

FIG. 7 shows an example in which the capacity control device according to the fifth embodiment of the present invention is applied to a reciprocating refrigeration compressor. In the figure, a piston 5 reciprocates up and down within a cylinder case 8. piston 5
When the refrigerant gas decreases, the refrigerant gas enters the compression chamber 12 via the suction chamber 9 and the suction passage lO1 suction valve 11.

When the piston 5 moves up, the gas in the compression chamber 12 is compressed, the discharge valve 13 is opened, and the gas is discharged into the discharge chamber 15 via the discharge passage 14 .

A capacity control device, which will be described below, is installed in a reciprocating refrigeration compressor that performs the suction and compression action of refrigerant gas as described above.

An unloader cylinder 17 is fixed to the center of the cylinder of the valve plate 16 with bolts 25.

The unloader piston 1 is inserted into the unloader cylinder 17 and can move up and down, thereby changing the top clearance volume 4.

At the bottom of the unloader cylinder 17 is a discharge valve inner valve seat 1.
8 is fixed with screws, Loctite, etc.

11.9 is the bolt 2 on the top of the unloader cylinder 17.
It is fixed at 0.

FIG. 8 shows an enlarged cross-sectional view of the unloader cylinder section. The lid 19 has a throttle hole 40 and a control gas passage 43. A rod 41 is attached to the center with a nut 42, and a piston ring 48 is attached to the tip of the rod 41. is fitted.

Further, a valve 44 is slidably fitted in the center of the rod 41 so that the valve 44 can move smoothly in the vertical direction of the rod 41. A valve seat 46 is fixed to the inner upper part of the unloader piston 1 by a snap ring 45, and the valve 44 is pressed against the valve seat 46 by a leaf spring 47. As mentioned above, small rooms 49, 50. When the space 2 is configured and oil is poured into a part of the space 2 and the small rooms 49 and 50, the rotating part acts as an oil damper for the unloader piston 1, and a braking force is generated by the vertical vibration of the unloader piston l.
Even when receiving pressure fluctuations in the compression chamber 12, the unloader piston 1 does not cause abnormal vibrations and vertical vibrations can be damped.

The unloader piston 1 moves up and down by increasing or decreasing the pressure in the space 2 from the average pressure in the compression chamber 12.

The pressure in the space 2 allows the gas flowing in from the throttle hole 40 and the gas flowing in from the gap between the unloader piston 1 and the unloader cylinder 17 into the control gas passage 43. Pipe 21. The flow rate of the control oil is controlled by the control valve 27 through the control oil inlet/outlet 22, and the oil is released from the outlet 24a to the intake gas side.

That is, by setting the pressure of the control valve 27, the vertical movement of the unloader piston 1 can be controlled, and the knob clearance volume 4 can be arbitrarily changed to achieve compressor capacity control.

Next, the sixth embodiment of the present invention is shown in FIG. 9, and the seventh embodiment is shown in FIG.
This will be explained using figures.

Note that everything other than what is shown in the drawings is the same as the fifth embodiment.

In the fifth embodiment, the top clearance volume is 4.
In the sixth embodiment, a top clearance volume 4 is provided on the side surface of the cylinder as shown in FIG. 9.

Further, the seventh embodiment has a cylinder case 8 as shown in FIG.
and the position of the valve plate 16 is changed. In FIG. 10, the cylinder case 8 and the valve plate 1 are driven by a drive source (not shown).
6 by the height h, the increase in trap clearance volume is -D2·h.

Next, an eighth embodiment of the present invention will be described with reference to FIG. Note that everything other than what is shown is the same as in FIGS. 7 and 8. 5th above
In the embodiment, the pressure in the space 2 was made to flow through the throttle hole 40, but in this embodiment, as shown in FIG. 11, the throttle hole 40 is installed near the center of the unloader cylinder.
It is effective in preventing garbage from clogging.

FIG. 12 is a diagram showing a ninth embodiment of the present invention, and is the same as FIGS. 7 and 8 except for what is shown. This embodiment is an example in which the gas leaked through the gap between the unloader piston 1 and the unloader cylinder 17 is utilized. When the control valve 27 shown in FIG. 7 is closed, the spring 51 shown in FIG. descend.

Next, a tenth embodiment of the present invention will be described with reference to FIG.

FIG. 13 shows an example in which high-pressure gas (discharged gas) is guided through a control valve 27. When the control valve 27 is closed, a spring 52 acts,
The unloader piston 1 can be lowered.

As described above, in the eighth to tenth embodiments, gas such as discharged gas is used as the pressure in the space 2, but it is of course possible to use other incompressible liquids, such as oil.

Incidentally, when oil is used, there is an advantage that in the refrigeration system, in addition to the oil pump outlet pressure oil, oil present in the oil separator or the like can be easily used.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

(1) Stepless capacity control of the compressor is possible, allowing fine control.

(2) There is no fluctuation of the unloader piston in response to compression, resulting in high efficiency and reduced operating costs.

(3) The unloader piston is stopped by incompressible fluid, resulting in low vibration and noise.

(4) Solenoid switching valve and control means For example, a simple sensor (
A practical and low-cost control device can be obtained because smooth capacity control can be performed using the 2-position type).

(5) When oil is used as the control fluid and the oil in the oil separator is used, a temperature switch is used as the control means, and the temperature rises after operation to reduce the amount of refrigerant in the oil. Since only oil can be used, it is effective in preventing malfunctions.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a first embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view of a multi-cylinder compressor according to a second embodiment of the present invention.
3 is an electric circuit diagram of a third embodiment of the present invention, FIG. 4 is a vertical sectional view of the third embodiment, FIG. 5 is a schematic functional diagram equivalent to the solenoid valve 30 of FIG. 4, and FIG. The figure is an electric circuit diagram of the fourth embodiment of the present invention, FIG. 7 is a longitudinal sectional view of the fifth embodiment of the present invention, and FIG.
The figure is an enlarged view of the vicinity of the center of Fig. 7, and Fig. 9 is the sixth embodiment of the present invention.
A vertical cross-sectional view of the vicinity of the valve plate 16 of the embodiment, FIG. 10 is a vertical cross-sectional view of the seventh embodiment of the present invention, FIG. 11 is a vertical cross-sectional view of the eighth embodiment of the present invention, and FIG. 12 is a longitudinal cross-sectional view of the eighth embodiment of the present invention. FIG. 13 is a vertical sectional view of the vicinity of the unloader piston 1 of the ninth embodiment of the present invention.
FIG. 14 is a longitudinal sectional view of the conventional example. 1---Unloader piston 2---Space (above the unloader piston) 3---3
Direction control valve 4---Top clearance volume 5---Piston 8---Cylinder case 9-m=Suction chamber 10---One suction passage 11---Suction valve
12-m-Compression chamber 13--Discharge valve
14-m-discharge passage 15--discharge chamber
16--Valve plate 17--Unloader cylinder 18-m-Discharge valve inner valve seat 19--Lid 21--Pipe 22--
1 Control oil inlet/outlet 23-0-High pressure oil pipe 24-m-Crankcase oil pipe 24a--One outlet 27--Control valve 30-
1 Solenoid cutoff valve 31-m-circuit 32-37---
Terminal 40--One throttle hole 41-- Rod
42---Nut 43---Control gas passage
44---One valve 45---Snap ring 46---
Valve seat 47---Plate spring 48---Piston ring 49, 50---One small chamber 51.52-One-spring Sl, S2-m-Switch (temperature switch) S3
-m-Current switch l, -m-Auxiliary relay mz-
−~Auxiliary relay T+−−Intermittent timer TH−
--Contact SV, 5Vz--Solenoid valve agent Patent attorney Akiga Itama 2 people Figure 2 Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 9 Figure 13 Figure 14

Claims (4)

[Claims] (1) In a capacity control device for a reciprocating gas compressor,
A capacity control device for a gas compressor, comprising a control mechanism that changes the top clearance volume steplessly or almost steplessly. (2) In a capacity control device for a gas compressor comprising a top clearance volume for capacity control communicating with a compression chamber, the top clearance volume is shaped like a cylinder, and an unloader piston is fitted in the cylinder in a sealed and slidable manner. A capacity control device for a gas compressor, characterized in that it is equipped with a control means for steplessly controlling the position of the unloader piston by controlling the pressure only in the cylinder space on the side opposite to the compression chamber of the unloader piston. . (3) In a gas compressor capacity control device that controls the capacity of a compressor by changing the volume of a gas compression chamber by moving an unloader piston in an unloader cylinder that communicates with the gas compression chamber, the A gas compressor comprising a control means for controlling the position of an unloader piston by supplying and discharging an incompressible fluid to a space between the unloader cylinder and the unloader cylinder on the side opposite to the side communicating with the gas compression chamber. Capacity control device. (4) In a gas compressor capacity control device that controls the capacity of the compressor by changing the volume of the gas compression chamber by moving an unloader piston in an unloader cylinder communicating with the gas compression chamber, the An electromagnetic switching valve that supplies, discharges, or closes incompressible fluid to the space between the unloader cylinder and the opposite side to the side that communicates with the gas compression chamber, and whether the controlled variable of the controlled object is higher than the two set values or and a control means for controlling the electromagnetic switching valve by selectively selecting one of two power supplies that are intermittently turned on and off when the temperature is low. Device.