JPH0315836Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of an oil-free screw vacuum pump.

[Conventional technology]

First, an outline of an oilless screw vacuum pump will be explained using FIG. 1 showing this embodiment.

1 is a suction cover, and 2 is a casing. Inside this casing 2, a pair of screw female rotor 3 and screw male rotor 4 (hereinafter simply referred to as rotors) are provided. The rotating shafts 21 and 22 of the pair of rotors 3 and 4 are supported by bearings 9, 10, 11, and 12 provided on the discharge cover 5. Reference numeral 19 denotes a sealed space, and oil for lubricating the bearings 9, 10, 11, and 12 is stored in this sealed space 19, and this oil is transferred from the sealed space 19 (atmospheric pressure) to the pair of rotors 3. ,4
Oil seals 7 and 8 are provided to prevent leakage to the casing 2 (vacuum pressure) side where the is housed.

The oil seals 7 and 8 play an important role in the vacuum pump.

That is, if the oil seals 7, 8 are damaged for some reason, the oil in the sealed space 19 will enter the casing 2, which is under vacuum pressure, due to the pressure difference.

As a result, the oil is mixed and carried in the air discharged from the discharge port 6, and the suction capacity of a reciprocating pump (not shown) connected to the discharge port 6 is reduced by the amount of oil.

Along with this, the amount of air sucked by the pair of rotors 3 and 4 also decreases, resulting in a decrease in the vacuum performance of the vacuum pump. Furthermore, if the pair of rotors 3, 4 and the vacuum container 28 become dirty due to the oil leakage, a similar result will occur.

In the figure, 14 and 15 are timing gears, 16
is a cover, 17 is a bearing, 18 is an oil seal, 2
0 is a coupling.

In this way, the oil seals 7 and 8 are important parts for the vacuum pump.
In the end, the protection in item 8 is nothing more than the protection of the vacuum pump.

The conventional protection of the oil seal is to prevent the temperature rise of the lubricating oil by water cooling or air cooling.
The vacuum pump was protected by preventing deterioration of the lip of the oil seal.

In addition, two or more oil seals were provided as a double protection measure, so that even if one oil seal deteriorated, it would be protected by another oil seal.

[Problem that the invention attempts to solve]

In the conventional vacuum pump protection described above, if water for cooling does not flow or air for air cooling does not flow for some reason, the temperature of the lubricating oil will rise rapidly. .

As a result, the lip of the oil seal deteriorates, causing oil leakage.

Additionally, when the temperature of the lubricating oil rises, the temperature of the shaft itself also rises, so even if two or more oil seals are installed, all the lips of these oil seals will deteriorate and oil will still leak. There was a problem.

Once such an oil leak occurs,
Since the rotor and vacuum chamber become dirty, it is necessary to disassemble the vacuum pump and clean it, which poses a problem of reducing the operating rate of the vacuum pump.

Furthermore, in the conventional protection device, the oil leakage is only recognized after the oil leakage occurs and the vacuum performance of the vacuum pump deteriorates, and the above-mentioned problem is unavoidable.

The present invention aims to provide a vacuum pump protection device that solves the above problems.

[Means to solve the problem]

That is, the present invention provides a vacuum pump in which the oil lubricating the bearings of a pair of rotors is sealed with an oil seal to prevent the oil from leaking to the rotor side. The present invention is characterized in that it includes a temperature sensor that detects temperature, and a control unit that stops the vacuum pump when the output from the temperature sensor reaches a certain value.

[Effect]

With this configuration, the temperature of the lubricating oil that directly affects the oil seal is detected, and the vacuum pump is activated when the temperature of the lubricating oil rises to a certain temperature before deterioration of the lip of the oil seal occurs. Stop.

This allows the cause of the temperature rise to be quickly repaired before the rotor or vacuum chamber becomes contaminated with oil.

〔Example〕

An embodiment of the present invention will be described in detail below.

In FIG. 1, 1 is a suction side cover, 2 is a casing, 3 is a female rotor, 4 is a male rotor (hereinafter simply referred to as rotor), 5 is a discharge side cover, 6 is a discharge port,
7 and 8 are oil seals, 9, 10, 11, and 12 are bearings, 13 is a bearing cover, 14 and 15 are tongue gears, 16 is a cover, 17 is a bearing, 18 is an oil seal, 19 is a sealed chamber, 20 is a coupling, 2
1 and 22 are rotor shafts, and 28 is a vacuum chamber.

Reference numeral 23 denotes an electric motor connected to the rotor shaft 21 via a coupling ring 20, and the pair of rotors 3 and 4 are driven by this electric motor 23.

As shown in FIG. 2, an oil seal space 29 is formed in the oil seals 7 and 8, and a temperature sensor 24 is provided facing the oil seal space 29. A lead wire 25 is electrically connected to this temperature sensor 24. Regarding other parts, the same parts as in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, 26 is a control section, which is electrically connected to the temperature sensor 24 and the electric motor 23 by lead wires 25 and wiring 27, and controls the temperature of the lubricating oil circulating in the oil seal space 29. It has a function of stopping the electric motor 23 when a set value (temperature determined by the material of the oil seals 7 and 8) is reached.

Alternatively, the control unit 26 may be used to disconnect the coupling 20, and in any case, it is sufficient as long as it stops the pair of rotors 3, 4.

In this embodiment configured as described above, during normal times, the lubricating oil stored in the closed space 19 is
Timing gears 14, 15 and bearings 9, 10, 1
1 and 12, passes through the oil seal space 29, and returns to the sealed space 19 again. During this circulation process, the lubricating oil flowing through the oil seal space 29 comes into direct contact with the oil seals 7 and 8, and the temperature of the oil seals 7 and 8 is also raised to a temperature close to that of the lubricating oil.

Then, for some reason, the oil seal space 2
When the temperature of the lubricating oil flowing through the motor 9 reaches the set temperature, the temperature sensor 24 detects the temperature, inputs it to the control section 26, and stops the electric motor 23.

Then, the cause of the temperature rise of the lubricating oil, for example, the water cooling system of the water cooling system is inspected and the cause is repaired in advance.

In addition, the control unit 26 or the temperature sensor 24
It is also possible to monitor the temperature of the oil seal and adjust the cooling system to maintain a constant temperature.

As a result, the temperature of the lubricating oil and the oil seal 7,
It is also possible to determine the periodic inspection period and protect and manage the vacuum pump based on the relationship with the material in item 8.

[Effect of idea]

As described in detail above, according to the vacuum pump protection device according to the present invention, a temperature sensor is provided facing the oil seal space, and the control unit is actuated based on the output signal of this temperature sensor, so that the vacuum pump can be prevented in advance. Since the pump is stopped, the oil stored in the sealed space will not leak into the casing housing the rotor, and the vacuum will not deteriorate.

Furthermore, since there is no oil stain on the rotor or vacuum chamber, there is no need to disassemble and clean it, which greatly shortens the repair time and greatly improves the operating rate of the vacuum pump.

Furthermore, monitoring the temperature of the lubricating oil circulating in the oil seal space is approximately monitoring the temperature of the oil seal, and the cooling system is controlled by the control unit based on the signal from the temperature sensor. It can adjust the temperature of the oil seal, extend its service life, and further improve the operation rate of the vacuum pump.

This has excellent effects such as determining the periodic inspection period for the oil seal and ensuring more reliable protection and management of the vacuum pump.

Further, the above-mentioned protection of the oil seal also protects the bearing portion, and has the effect of achieving protection of the vacuum pump as a whole.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention,
Fig. 1 is a plan view showing an example in which the present invention is applied to a vacuum pump, showing only the vacuum pump in cross section, and Fig. 2 is a cross sectional view of part A in Fig. 1 showing an enlarged view of the oil seal space. It is. 3, 4... Pair of rotors, 7, 8... Oil seal, 9, 10, 11, 12... Rotor bearing section, 24... Temperature sensor, 26... Control section, 29
...Oil seal space.

Claims (1)

[Scope of utility model registration request] In a vacuum pump that is sealed with an oil seal to prevent the oil lubricating the bearings of a pair of rotors from leaking to the rotor side, the temperature of the lubricating oil is detected by looking into the space of the oil seals. A vacuum pump comprising a sensor and a control unit that stops the vacuum pump when the output from the temperature sensor reaches a certain value.