KR19980019592A - A water-cooled cooling device of screw type of a vacuum pump - Google Patents

Abstract

[Technical Field]

The present invention relates to a water-cooled chiller of a screw type vacuum pump.

[Technical problem to be solved]

Conventional screw-type vacuum pump uses the air-cooled cooling method to lower the discharge temperature by introducing air or cooled air through the air inlet of the casing wall as shown in Figure 6 attached to the drawing, such a method is very low cooling effect The reality is that the temperature near the discharge port is no longer lowered below about 250 ° C.

[Summary of solution]

The present invention forms a screw inside the empty space in order to increase the cooling efficiency of the screw rotor and exhaust gas, and the screw shaft portion is composed of a double pipe to circulate the cooling water so that the cooling of the screw portion can be efficiently It is to make it possible to cool exhaust gas efficiently.

[Use of the invention]

Transfer of gas used in semiconductor industry, electronics industry, medicine, food industry, etc.

Description

Water-cooled chiller of screw type pump

The present invention relates to a water-cooled chiller of a screw-type vacuum pump for circulating the cooling water inside the screw-rotor to cool the water in a screw-type vacuum pump to reduce the temperature of the air and gas transferred to the screw rotor and the inner chamber of the screw. .

In general, screw type vacuum pumps have a compressor-like structure and are generally used in places where the pressure of suction gas is very low. For example, when the suction pressure is 0.1ata (76 Torr) or 0.01ata (7.6 Torr), the discharge side of the vacuum pump is under atmospheric pressure, and the temperature of the discharge gas continuously rises to a very high temperature during the adiabatic compression process of the gas. .

Here, the temperature Td (° K) of the discharge gas can be represented by the formula Td = Ts (P2 / P1) ^{(K-1) / K.} Where P1 is the suction pressure, P2 is the discharge pressure, TS (° K) is the temperature of the suction gas, and K (1.4 for air) is the specific heat of the gas.

Therefore, when the suction pressure is lowered from 0.01 Torr to 0.001 Torr, the pressure ratio P2 / P1 becomes very large and the temperature Td of the discharge gas rises to a very high temperature. For example, the temperature Td of the discharge gas is 317 ° C or 867 ° C when the air at 30 ° C has a suction pressure P1 of 0.1 atta by a screw type vacuum pump. The degree of vacuum is a relatively low value, but the temperature rises to a very high temperature. In order to lower the discharge gas temperature, the screw-type vacuum pump currently in use uses an air-cooled cooling method that lowers the discharge temperature by introducing atmospheric air or cooled air through the air inlet of the casing wall as shown in FIG. have. However, this method is so low that the cooling effect is so low that the temperature near the discharge port is no longer lowered below about 250 ℃. In particular, during the vacuum process, vaporous substances that generate carbides are also discharged in the chemical composition of the exhaust gas, which promotes carbonization with metals at high temperatures to form a carbonized layer on the screw surface. And the casing causes heat sintering, and also due to the volume expansion of the rotor is in close contact with the inner surface of the casing is a big problem that damages the vacuum pump due to excessive rotation of the rotor.

The present invention has been made in order to solve such a problem is to form a screw inside the empty space in order to increase the cooling efficiency of the screw rotor portion and exhaust gas, double screw out portion so that the cooling of the screw portion can be efficiently It is configured to make the cooling of the screw and the exhaust gas by circulating the cooling water by configuring the pipe as described above according to the accompanying drawings as follows.

1 is a cross-sectional view of the left and right screw rotor of the present invention

2 is an enlarged view of part A of FIG.

3 is an enlarged view of part B of FIG.

4 is a longitudinal cross-sectional view of the present invention.

5 is a cross-sectional view of the present invention.

6 is an illustration of a screw type vacuum pump of the conventional structure

* Explanation of symbols for main parts of the drawings

DESCRIPTION OF SYMBOLS 1 Inlet port, 2 discharge port, 3 pump casing, 4 drive screw rotor, 4a drive shaft, 5 driven screw rotor, 5a driven shaft, 6,6 'timing gear, 7 cooling water circulation chamber, 8 Coolant inlet,

9,9 ': Cooling water discharge pipe, 10: Cooling water drain hole, 11: Cooling water discharge port, 12: End housing

The drive screw rotor 4 and the driven screw rotor 5 which are simultaneously rotated in conjunction with the drive screw rotor 4 in the pump casing 3 provided with the suction port 1 and the discharge port 2 are engaged with the timing gears 6 and 6 '. In the conventional screw-type vacuum pump which is rotated at the same time by the engagement rotation of (), the inside of the drive screw rotor (4) and the driven screw rotor (5) is formed into an empty space to form a cooling water circulation chamber (7) A driving shaft tube 4b and a driven shaft tube 5b, which have a cooling water inlet hole 8 drilled at the other end of each of the screw rotors 4 and 5, which are tightly compressed to the driving shaft 4a and the driven shaft 5a, are brought into contact with each other. Cooling water discharged inside the screw rotor (4) (5), the drive shaft tube (4b) and the driven shaft tube (5b) by abutting the screw rotor (4) (5), the drive shaft tube (4b), and the driven shaft tube (5b). Insert the pipes (9) and (9 '), the leading end of which the cooling water drain hole (10) is drilled into the drive shaft (4a) and the driven shaft (5a), and the other end of the cooling water discharge port (11) A structure in which hayeoseo installed to be supported by the end housing 12 of the casing (3).

In the drawings, reference numeral 13 denotes a bearing, and 14 denotes an oil seal or a mechanical seal.

In the present invention, the operation of the screw-type vacuum pump is such that the power transmitted to the drive shaft 4a of the drive screw rotor 4 by the driving of the motor rotates the timing gears 6 condensed at the same time and at the same time By rotating the timing screw 6 'with the number of teeth to rotate the driven screw rotor 5, the driving and driven screw rotors 4 and 5 simultaneously move in opposite directions to discharge the air sucked into the inlet 1 It is discharged to (2) in this process, the temperature of the screw rotor and the discharge gas is overheated to a very high temperature causing various problems as is known.

However, in the present invention, the inner space of the drive screw rotor 4 and the driven screw rotor 5 is formed into a vacant space to form a coolant circulation chamber 7 and a drive shaft tube 4b having a coolant inlet 8 drilled at one end thereof. ) And the driven shaft pipe 5b are connected to each other, and the cooling water discharge pipes 9 and 9 'are inserted into and inserted into the drive shaft pipe 4b and the driven shaft pipe 5b. When the coolant is supplied to the coolant 8 of the coolant, the coolant flows into the coolant circulation chamber 7 inside the driven and driven screw rotors 4 and 5 through the coolant discharge pipes 9 and 9 '. While being introduced along the inner wall of the screw rotors 4 and 5 by the rotation of the shaft, the superheated screw rotors 4 and 5 and the gas discharged by suction are cooled by heat exchange.

On the other hand, the cooling water transferred to the front while the heat exchange is made by the transfer of the screw rotor (4) (5) is introduced into the cooling water drain hole (10) opened at the tip of the cooling water discharge pipe (9) (9 ') and the cooling water discharge pipe ( 9) (9 ') is a continuous water cooling process by the discharge method.

Thus, the present invention effectively cools the screw rotor by water cooling to prevent volume expansion of the screw rotor, thereby eliminating the problem of heat sintering between the screw rotor, the screw rotor and the casing, thereby eliminating the shortening of the life of the vacuum pump due to abrasion or burnout. The cooling of the gas is performed smoothly, which has the advantage of lowering the temperature of the hot exhaust gas by the compressed discharge, and the inside of the screw rotor becomes an empty space, and the weight is significantly reduced, thereby reducing the rotation torque by the screw rotor's own weight at the beginning of rotation. It is an excellent invention that reduces the initial starting torque, reduces the product, reduces the material cost, and greatly reduces the operating power cost.

Claims (1)

In a screw-type vacuum pump having a pair of drive and driven screw rotors (4) and (5), the cooling water circulation chamber (7) is formed with an empty space inside the screw rotor, and a drive shaft tube ( 4b) and the driven shaft tube 5b are connected to each other, and the cooling water discharge tube 9 and 9 'is inserted thereinto provide a cooling water inlet 8 of the drive shaft tube 4b and the driven shaft tube 5b. Cooling apparatus for a screw-type vacuum pump, characterized in that the cooling water flows into the cooling circuit of the screw rotor through the cooling water to the screw rotor and the heat exchanged coolant is discharged to the cooling water discharge pipe.