JPS6349577Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for cooling oil for cooling an oil-cooled compressor.

Prior Art In oil-cooled compressors that use oil to absorb the heat generated by compressing gas, it is necessary to cool the oil, so oil is normally cooled by circulating oil through an oil cooler a, as shown in Figure 1. However, since the oil becomes supercooled when the oil is blocked or under light load, a bypass passage c, which is opened and closed by a thermostat valve b, is provided to bypass the oil cooler a, and when the oil temperature is low, the thermostat The oil is made to flow directly from the valve to the compressor d through the bypass passage and not to the oil cooler a.

In FIG. 1, e is the engine, f is the receiver tank, and g is the oil filter.

However, this device has the following problems.

In other words, if the engine is started with high oil viscosity during cooling, the thermostat valve B will close while the oil temperature is low.
As a result, oil normally flows through bypass path c to compressor d, but when the oil temperature rises and thermostat valve b is activated to switch the oil to flow to oil cooler a, the oil is rapidly cooled. Since the viscosity increases, it becomes difficult to flow inside the oil cooler a.

As a result, the flow rate of oil temporarily decreases and the supply of oil into the compressor d decreases, resulting in insufficient cooling, and the temperature of the discharged air increases abnormally.

As a result, the discharge air temperature sensor may detect this and activate an emergency stop device normally installed in the compressor, thereby stopping the engine e.

Purpose of the invention: At the initial stage when oil flows into the oil cooler, a portion of the oil can flow directly to the compressor without passing through the oil cooler, preventing a temporary drop in oil flow rate and causing compressor cooling failure. The purpose is to ensure that there are no

Structure of the invention A second bypass path is provided with a relief valve that operates in relief when the differential pressure between the inlet pressure and the outlet pressure of the oil cooler exceeds a predetermined value, and the inlet and outlet are short-circuited.

Embodiment FIG. 2 is an overall schematic explanatory diagram, in which the compressor 1 is driven by an engine 2, its compressed air is supplied to a receiver tank 3, and cooling oil is supplied to the receiver tank 3 through a first pipe 4. is supplied to the inlet 6a of the oil cooler 6 through the second pipe line 5, and the outlet 6b is supplied to the compressor 1 through the third pipe line 7.
The second and third pipes 5 and 7 are short-circuited through a thermostatic valve 8 and a first bypass path 9, and are also short-circuited through a relief valve 10 and a second bypass path 11.

FIG. 3 is a schematic explanatory diagram of the oil cooler 6,
The Atsupa tank 12 and the lower tank 13 are communicated through a number of tubes 14, and the Atsupa tank 12 is provided with a partition wall 15 to divide it into first and second chambers 12 ₁ and 12 ₂ , and the first chamber 12 ₁ has an inlet 6 a. , 2nd room 1
2 ₂ is formed with an outlet 6b, and an inlet 6a and the partition wall 1
A thermostatic valve 8 is provided at the first bypass inlet 16 of the first bypass inlet 5 .

FIG. 4 is a detailed sectional view of the thermostat valve part, and the thermostat valve 8 consists of a lid body 18 that is fixed to the upper tank 12 and has an opening 17, and a cylinder body 19 that moves up and down with respect to the lid body 18. This is a conventionally known bellows-type thermostatic valve equipped with a bellows 20 that expands and contracts according to temperature changes, and the cylindrical body 19 connects to the first bypass inlet 16 of the partition wall 15.
When the oil temperature is low, the bellows 20 contracts and the cylindrical body 19 comes into close contact with the lid body 18, and the valve seat below the first bypass inlet 16 is fitted in a fluid-tight manner. Separated from 22, oil enters an inlet 6a,
The oil flows directly from the opening 17, the cylindrical body 19, and the first bypass inlet 16 to the second chamber ₁₂₂ , and when the oil temperature is high, the bellows 20 extends and the cylindrical body 19 comes into close contact with the valve seat 22, allowing the oil to flow through the first bypass inlet 16. The oil flows through the inlet 6a and opening 17 to the first _chamber 121, through the tube 14 to the lower tank 13, again through the tube 14 to the second chamber 122 of the upper tank ₁₂ , and through the outlet 6b to the compressor 1. When flowing through the tube 14, the air is cooled by the air blown by the fan 23 driven by the engine 2.

The atsupa tank 12 has a first chamber 12 1 , a second chamber 12 ₁ ,
An inlet hole ₃₀ and an outlet hole 31 constituting the second bypass path 11 communicating with the second bypass passage 12 are formed, and a large diameter hole 32 concentric with the inlet hole 30 is formed.
A valve 33 is fitted into this large diameter hole 32, and this valve 33 is attached to the peripheral edge 30a of the inlet hole 30 by a spring 34.
The relief valve 10 is constructed by crimping the inlet hole 30 and the outlet hole 31, and
The spring chamber 34a is opened and communicated with the second chamber ₁₂₂ through a pipe 35, and the valve 32 is pushed in the blocking direction by the pressure of the second chamber ₁₂₂ and the spring force of the spring 34,
The pressure in chamber 12 ₁ will push it in the opening direction,
The valve 32 controls the pressure P 1 in the first chamber 12 ₁ and the pressure P ₁ in the second chamber 12 _{2 .}
The inlet hole 30 and the outlet hole 31 are opened in an opening direction in which the difference P ₁ -P ₂ from the pressure P ₂ is greater than a certain value, and the inlet hole 30 and the outlet hole 31 are communicated with each other.

Because of this, as mentioned above, when the thermostat valve 8 opens and oil starts to flow from the first chamber 121 to the lower tank ₁₃ through the tube 14, the flow rate decreases due to the flow resistance of the tube 14. , the pressure P ₁ in the first chamber 12 ₁ increases, and the pressure in the second chamber 12 1 increases.
Since the pressure P ₂ in the chamber 12 ₂ becomes low, the differential pressure P ₁ −P ₂ becomes a predetermined value or more, and the valve 33 opens.
A part of the oil flows from the inlet hole 30 through the output hole 31 to the second
Flows to chamber 12 ₂ and from the second chamber 12 ₂ to compressor 1
This prevents cooling failure due to insufficient flow rate and prevents the discharge air temperature from rising abnormally.

Then, after a certain amount of time has passed, the viscosity of the oil decreases and it flows smoothly into the lower tank 13, so the pressure P ₁ in the first chamber 12 ₁ decreases, and the pressure difference P ₁ - _{P 2}
is below the predetermined value, the valve 33 is in the cutoff position, and the entire amount of oil flowing from the inlet 6a is discharged into the first chamber 1.
2 ₁ , so you can get the same cooling effect as normal.

In addition, although the differential pressure between the first chamber 12 ₁ and the second chamber 12 ₂ is detected in the above embodiment, the pressure difference between the inlet 6 a and the outlet 6 b is detected and the relief valve 10 is activated. All you have to do is activate it.

Effect of the invention: When the flow rate of oil flowing through the oil cooler 6 decreases due to the influence of viscosity number at the beginning of oil flowing into the oil cooler 6, the pressure difference between the inlet 6a and the outlet 6b becomes large and the relief valve 10 is activated. , some of the oil flows directly to the outlet 6 without passing through the oil cooler 6.
b, the oil can flow to the compressor 1, preventing a temporary drop in the oil flow rate and preventing the compressor from cooling poorly.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of a conventional example, Fig. 2 is an overall schematic explanatory diagram showing an embodiment of the present invention, Fig. 3 is a schematic explanatory diagram of an oil cooler, and Fig. 4 is a detailed sectional view of a thermostat valve part. It is. 1 is a compressor, 6 is an oil cooler, 6a is an inlet, 6b is an outlet, 8 is a thermostatic valve,
9 is a first bypass path, 10 is a relief valve, 1
1 is the second bypass road.

Claims (1)

[Scope of utility model registration request] The oil outlet of the compressor 1 and the inlet 6a of the oil cooler 6 are connected, and the outlet 6b and the oil inlet are connected, and the inlet 6a and the outlet 6b of the oil cooler 6 are connected to a first bypass equipped with a thermostatic valve 8. It is characterized in that the inlet 6a and the outlet 6b are short-circuited at the passage 9, and the second bypass passage 11 is provided with a relief valve 10 that is operated by the pressure difference between the inlet 6a and the outlet 6b. Oil cooling system for oil-cooled compressors.