JPS5851429Y2 - Load reduction device for rotary compressor startup - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for reducing the load upon startup of a rotary compressor, that is, an improvement to a starting unloader.

Normally, when starting a rotary compressor, the intake blocking unloader valve opens, so the load capacity at the time of starting is large, which may cause the engine or motor of the prime mover to be unable to start or be damaged.

In order to prevent such accidents, starting unloaders are often used in which the unloader pulp is closed at the time of startup.

The starting unloaders that have been used in the past have disadvantages such as a complicated structure, a large device, and a high cost.

In view of these drawbacks, the present invention provides a start-up load reduction device for a rotary compressor that is small, lightweight, low cost, and easy to replace and reassemble.

First, a conventional start-up load reduction device for a rotary compressor will be explained with reference to FIGS. 1 and 2.

Figure 1 is a piping route diagram of a rotary compressor.
FIG. 2 is a sectional view of a conventional startup load reduction device.

In FIG. 1, 61 is a slide vane type, screw type, etc. rotary compressor, and clean air from which dust has been removed by an air cleaner is compressed by the rotary compressor 61 through an unloader 62 having a startup load reduction device. Receiver tank 63 through check valve 66° pipe 68
The air is discharged through the pipe line 65 and supplied to air tools and the like.

On the other hand, oil supplied for lubrication, sealing, and cooling of the rotary compressor 61 is supplied to the check valve 66 and the conduit 6 along with the compressed air.
8 and discharged into a receiver tank 63, separated from compressed air, cooled by an oil cooler 67, passed through a pipe 69, supplied to a rotary compressor, and recirculated.

When the receiver tank 63 pressure becomes equal to or higher than the set pressure of the regulator 64 (for example, 7kycIIL), the regulator 64. The receiver tank pressure is introduced into the unloader 62 via the pipe line 19, and the unloader 62 controls the intake air volume to keep the receiver tank 63 pressure constant.

In FIG. 2, the unloader pulp 1 is in contact with one of the seat surfaces 3 and 4 of the body 2 and closes the suction passage 5.

The unloader pulp 1 is connected to a piston 8 via a rod 6 and a spring 7, and when the rotary compressor is stopped, the unloader valve 1 is brought into contact with the seat surface 3 by the tension of the spring 7.

The piston 8 is movable left and right within the cylinder 9, and is always pushed to the right by the tension of the spring 7.

The rod 6 passes through the piston 8 and connects to the other piston 10.
make it come into contact with.

The operation of a conventional rotary compressor start-up load reduction device will be explained with reference to FIGS. 1 and 2.

Before starting the rotary compressor 61, the piston 8.
The unloader valve 1 is located as shown in FIG.

That is, the unloader valve 1 is in contact with the seat surface 3,
The suction passage 5 is closed.

A small vent hole 11 is provided in the unloader valve 1, and when the compressor is started, the unloader valve 1 takes in a small amount of air through the vent hole 11 while remaining closed, and the internal pressure of the receiver tank 63 gradually increases.

Since the rotary compressor 61 is activated by only inhaling a small amount of air, the load on the prime mover is reduced.

The pressure in the receiver tank 63 is introduced through the hole 13 into the right working chamber 12 of the piston 10 via the conduit 18 (FIG. 1), and applies a force to the right side of the piston 10 that overcomes the tension of the spring 7. When the receiver tank pressure reaches the desired level (for example, 2 kg//cr/L), the piston 10 moves to the left, the unloader valve 1 at the tip of the rod 6 separates from the seat surface 3, the unloader valve 1 opens, and the rotary compressor 61 enters full load operation.

When the receiver tank pressure becomes equal to or higher than the set pressure of the regulator 64 (for example, 7 klcrl), the regulator, which is a capacity adjustment device, is activated, and the operating pressure from the regulator 64 is introduced into the chamber 14 through the hole 15 via the pipe line 19, and the piston Move 8 further to the left.

This causes the unloader valve 1 to come into contact with the seat surface 4,
The suction passage 5 is closed and the rotary compressor 61 enters a no-load operation.

In this way, the conventional rotary compressor start-up load reduction device has separate seat surfaces 3 that are closed at startup and seat surfaces 4 that are closed when adjusting capacity, and the unloader valve is in contact with seat surface 3. The movement of the unloader valve is large, and the diaphragm cannot be used, making the device itself very difficult to operate. It has many drawbacks, such as being large and expensive.

The present invention eliminates these drawbacks and provides a start-up load reduction device for a rotary compressor that is small and lightweight, can be manufactured at low cost, and can be easily replaced with a standard unloader.

FIG. 3 shows one embodiment of the present invention.

The piping route diagram is the same as that shown in FIG.

In the figure, large arrows 16 and 17 indicate the intake and outflow directions of intake air, and small arrows 18 and 19 indicate the introduction path of working pressure.

The unloader valve 21 is formed integrally with the rod 22,
One end thereof is connected to the diaphragm 23, and a first spring 25 is interposed between it and the body 24.

Due to the tension of the first spring 25, the unloader valve 21 is pressed against the first seat surface 26 when stopped.
Block the suction passage.

A small-diameter ventilation hole 28 leading from the center of the unloader pulp disc 210 to the periphery of the unloader valve is provided so as to communicate with the portions of the first sheet surface before and after the gas passage. A second sheet surface 30 is formed around the opening of the central ventilation hole 28 of the unloader bolt 210 disc.

The on-off valve 29 has a valve shaft 31 extending on the opposite side of the rod of the unloader valve 21 and is connected to a diaphragm 33 via a second spring 32 .

The chamber 34 on the right side of the diaphragm 33 receives pressure from the receiver tank through the line 18. It is introduced through the hole 35.

In its operation, before the rotary compressor 61 is started, the unloader valve 21 is closed and the on-off valve 29 is open, as shown in FIG.

After the rotary compressor 61 is started, the on-off valve 29 is opened, and a small amount of air is introduced into the suction passage 27 through the ventilation hole 28, so that the load on the rotary compressor is small and the prime mover starts and rotates smoothly.

The internal pressure of the receiver tank 63 increases little by little, and the
Receiver tank pressure is also introduced into the working chamber 34 via.

The pressure load acting on the diaphragm 33 causes the spring 3
Pressure greater than the total tension of 2 and 25 (e.g. 2kri)
, the on-off valve 29 comes into close contact with the second seat surface 30,
The suction passage is closed, the unloader valve 21 is separated from the first seat surface 26, a large amount of air is sucked in, and the rotary compressor enters load operation.

Furthermore, the receiver tank pressure increases and the regulator 64
When the pressure exceeds the set pressure (for example, 7ky/ff1), the operating pressure from the regulator 64 is introduced into the operating chamber 36 via the pipe 19 through the small hole 37, and the diaphragm 23 is operated to open the on-off valve 29. The gap between the unloader valve 21 and the first seat surface 26 is closed while the valve is tightly closed.
Adjust the capacity by putting the rotary compressor in a no-load operating state.

As described above, according to the present invention, since the unloader valve 21 only performs one movement, it is possible to reduce the opening/closing lift (travel stroke) of the unloader valve 21, and a diaphragm can be used, making it smaller, lighter, and less expensive than the conventional type. Manufactured at low cost.

That is, the diaphragm is generally made of rubbery material;
Although it is lighter and cheaper than a piston, since it utilizes the elastic deformation of rubber, it cannot be used as a movement mechanism for an unloader valve that has a large movement stroke.

In the present invention, the movement stroke of the unloader valve can be made smaller than that of the conventional one, so a diaphragm can be used, and the device can therefore be made smaller, lighter, and lower in cost.

FIG. 4 shows another embodiment of the present invention, which is even smaller and lighter by using only one diaphragm for opening and closing the unloader valve.

In the figure, parts that perform the same functions as in FIG. 3 are designated by the same numbers.

The unloader pal 7'41 has a hole 42 penetrating a part of the rod 43 of the unrotor valve in the center and a second seat surface 44.
A small-diameter ventilation hole 45 is opened obliquely into the second seat surface 44, and is formed so as to communicate the portions of the first seat surface 71 before and after the gas passage.

A valve seat 46 is provided in the middle of the rod 43, and a second spring 47 is interposed between the rod 43 and the unloader valve 41, so that the valve seat 46 is normally open.

By the diaphragm 23 on the left side extension of the rod 43,
Chambers 4B and 49 are formed to divide the working chamber, the first spring 25 is arranged on the chamber 48 side, and the unloader valve 41
The system is designed to always close when stopped.

The chamber 49 is provided with a hole 50 for introducing the pressure of the receiver tank 63 through the pipe line 18, and the other chamber 48 is provided with a hole 50 for introducing the operating pressure from the regulator 64 through the pipe line 19.
To explain the operation in the case of this embodiment, when the rotary compressor is started, the unloader valve 41 closes and a small amount of air is sucked in through the ventilation hole 45, reducing the load as much as possible during startup. are doing.

When the receiver tank pressure gradually increases, the pressure in the chamber 49 also gradually increases through the pipe line 18 and the hole 50, and the diaphragm
The load applied to the compressor 23 overcomes the tension of the first spring 25 and moves to the left, the unloader valve 41 is opened, and the rotary compressor enters load operation.

At this time, the on-off valve 46 remains open.

When the receiver tank pressure rises above the set pressure of the regulator 64, the operating pressure is introduced from the regulator 64, which is a capacity adjustment device, into the chamber 48 through the hole 51 via the pipe line 19, and is added to the tension of the springs 25 and 47. With the load,
The rod 43 is moved to the right, the valve 41 is closed, and the opening/closing valve 46 is also brought into close contact with the second seat surface 44 of the valve 41, completely blocking the suction passage and causing no-load operation of the rotary compressor.

In this way, in the embodiment shown in Fig. 4, only one part, the diaphragm, is used, so the entire device becomes even more compact.
You can see that it can be done at low cost.

The rotary compressor start-up load reduction device of the present invention has a smaller movement stroke of the unloader valve than conventional start-up load reduction devices, so it is possible to use a diaphragm, making the entire device smaller and lighter. became possible.

In addition, the unload valve only needs to be provided with one large and one small seat surface, and processing and finishing can be facilitated, resulting in a significant cost reduction, which is extremely effective.

[Brief explanation of drawings]

FIG. 1 is a piping route diagram of a rotary compressor. FIG. 2 shows a sectional view of a conventional startup load reduction device. FIG. 3 is a cross-sectional view of a start-up load reduction device showing one embodiment of the present invention, and FIG. 4 shows another embodiment. 1.21.41... Unloader valve, 23.
...Diaphragm, 25... Spring for starting unloader, 11, 28, 45...
...Vent hole, 29.46...Opening/closing valve, 32,47...Spring.

Claims (1)

[Scope of utility model registration request] In a rotary compressor having an intake blocking type unloader, the unloader valve includes a first seat surface that seals an intake passage, and a small diameter passage provided in the unloader pulp so as to communicate the portions of the first seat surface before and after gas passage. providing a second seat surface that seals the pores, and providing a first spring that seals the first seat surface and a second spring that opens the second seat surface when the rotary compressor is stopped; Such as adjusting the suction capacity of the rotary compressor by opening the first seat surface due to low receiver tank pressure, while sealing the first and second seat surfaces by a regulator sensing high receiver tank pressure. A start-up load reduction device for a rotary compressor, which is characterized by: