JPH07217570A - Pressure abnormality detecting device for oil rotary vacuum pump - Google Patents

Abstract

PURPOSE:To rapidly and accurately detect the increase of a pressure in an oil tank case and to prevent the occurrence of a leakage trouble of exhaust gas and a breakage accident of a pump. CONSTITUTION:An opening end is located under an oil level in the oil tank case 3a of an oil rotary vacuum pump 1 and a pressure gauge 20 is attached to a pipe member 19 led out in a leak tight state from the oil tank case to the outside of a pump. Based on an output signal from the pressure gauge, a relay contact for protecting and stopping a pump and an abnormal signal are taken out. A piping for oil bubbler is sued as the pipe member. Further, it is preferable that a reference pressure based on which pressure abnormality is detected by the pressure gauge 20 is set to a range of approxmmately 1.5-3kg/cm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure abnormality detecting device for an oil rotary vacuum pump, and more particularly to an improvement of an oil rotary vacuum pump used in various vacuum equipment fields.

[0002]

2. Description of the Related Art As an example, a schematic structure of a conventional two-stage oil rotary vacuum pump is shown in FIG. In FIG. 3, the main body 1 of the oil rotary vacuum pump is composed of a motor unit 2 and a pump unit 3, a cooling fan 13 is connected to the tip of the motor shaft 2 a, and is directly connected to the rotary shaft of the pump unit 3. ing. The pump section 3 is provided with a pump mechanism section 3b inside the oil tank case 3a, and the pump mechanism section 3b operates while being immersed in the oil 4 stored in the oil tank case 3a. The oil 4 is supplied little by little from the oil pump 7 to the pump chambers 5 and 6 of the pump mechanism portion 3b so as to circulate, and the gas sucked from the intake port 8 is the first-stage pump chamber 5
Is compressed by the rotation of the rotor 9a and the vane 10a, and is sent to the second-stage pump chamber 6. At this time, the oil pump 7
The small amount of oil 4 supplied from the oil not only lubricates mechanical parts but also serves as a vacuum seal for various parts and as a heat dissipation medium. In the second-stage pump chamber 6 as well as in the first-stage pump chamber 5, the gas compressed by the rotor 9b and the vane 10b pushes up the exhaust valve 11c, is discharged into the oil tank case 3a, and is exhausted from the exhaust port 12. . Further, when the amount of exhaust gas is large, the exhaust valves 11a and 11b are pushed up by the compression of only the first-stage pump chamber 5 and exhausted.

FIG. 4 shows an oil rotary vacuum pump used when exhausting a dangerous gas or the like, and is a schematic view of an oil rotary vacuum pump to which additional equipment is attached. In this oil rotary vacuum pump, as an additional facility, for example, an inert gas purge port 2
1 is attached, and the inert gas 22 is introduced into the inside of the pump 1 to prevent the dangerous gas from being diluted and the gas from staying in the pump. When exhausting a condensable gas or the like, a gas ballast 23 for introducing an inert gas 22 is attached to the second-stage pump chamber 6 in order to efficiently exhaust such a gas without condensing it. There are also things. Further, when exhausting corrosive gas or the like, in order to prevent these gases from dissolving into the oil and deteriorating the oil 4 early, an inert gas 22 is introduced into the stored oil 4,
An oil bubbler 24 for bubbling oil is attached.
Other configurations are the same as those of the oil rotary vacuum pump described in FIG.

In the oil rotary vacuum pump having the above structure,
Normally, exhaust can be performed up to a pressure of about 10 ⁻⁴ Torr on the intake side, and exhaust can be performed on the exhaust side at a pressure of about atmospheric pressure. Further, as a protection device for such an oil rotary vacuum pump, usually, a thermal protector, a thermal relay, a fuse, a motor breaker, etc. are properly mounted to prevent the motor from being burned by heat.

[0005]

However, in the conventional apparatus, particularly in the case of exhausting a gas that produces a reaction product, when the exhaust pipe ahead of the exhaust port is clogged for some reason, the exhaust gas is exhausted. As a result, resulting in exhaust gas leaks from pipe connections,
In some cases, the gaskets 15a and 15b of the pump, the oil level meter 16 and the like are destroyed, and the exhaust gas leaks from there.

Further, the oil rotary vacuum pump is generally equipped with a motor having a relatively sufficient output so that the pump can be easily started even when the viscosity of the oil is hardened in cold weather. When the exhaust pipe is clogged by something or the like, it may act as a compressor that pressurizes the exhaust port side. In addition, since such vacuum piping equipment is generally designed for external pressure, it is not very resistant to internal pressure rise, and leakage may occur even for relatively low pressure rise. There is.

In the oil rotary vacuum pump used for manufacturing facilities for semiconductors and electronic parts, the exhaust port side pipe is regularly disassembled and cleaned to prevent the above accidents. Due to various factors such as changes in equipment operating status and exhaust gas type, changes in exhaust gas and cycle temperature, exhaust pipe history and exhaust gas treatment equipment status, the exhaust pipe is clogged earlier than regular maintenance. In some cases, the above-mentioned problems may occur.

The effectiveness of the protective device usually used in the above case is, for example, 1.1.
Fig. 5 shows the change of motor current value with respect to the pressure increase in the oil tank case of the oil rotary vacuum pump of the pumping speed 700 l / min. class equipped with the kw motor. As shown in FIG. According to the data shown in these figures, neither the motor current value nor the temperature of the pump body shows a remarkable change that can be used as pressure protection against the pressure rise on the exhaust side, and the thermal relay and fuse It can be seen that it is not appropriate to use protective equipment such as the above as pressure rise protection in the oil tank case.

Further, in recent semiconductor and electronic parts manufacturing lines, a large amount of extremely harmful gas, which is extremely harmful, and dangerous gas which may explode when leaking into the atmosphere are used. If such an exhaust gas leakage accident occurs, it may cause a serious accident.

An object of the present invention is to solve the above problems, detect a pressure increase in an oil tank case quickly and accurately, and prevent an exhaust gas leakage accident and a pump damage accident in advance. To provide a pressure abnormality detection device.

[0011]

In order to achieve the above-mentioned object, a pressure abnormality detecting device for an oil rotary vacuum pump according to the present invention has an opening end below the oil level inside the oil tank case of the oil rotary vacuum pump. In addition, it is configured to install a pressure gauge on the pipe member that is leaktightly taken out of the oil tank case to the outside of the pump, and can extract the relay contact for pump protection stop and abnormal signal based on the output signal of this pressure gauge. ing.

In the above construction, preferably, the pipe member is a pipe for an oil bubbler. Further, the reference pressure for detecting pressure abnormality with the pressure gauge is 1.5 to 3 kg / c.
It is desirable to set in the range of about m ² .

[0013]

In the pressure abnormality detecting device for the oil rotary vacuum pump according to the present invention, the pressure rise in the oil tank case and the pipe after the exhaust port can be immediately detected, and the pump can be protected and stopped. It is possible to prevent the gas leakage and the pump damage due to pressurization.

It is also possible to monitor these pressures with a pressure gauge attached to a pipe having an open end on the oil surface in the oil tank case, or a pressure gauge attached to a part of the exhaust port pipe, but it may be corroded. When exhausting a volatile gas or the like, the pressure gauge installed in this way is exposed to the exhaust gas and may deteriorate early. Therefore, by detecting the pressure through the oil using a pipe member having an open end below the oil surface, exhaust gas does not come into direct contact with the pressure gauge, so there is no need to particularly consider the corrosion resistance of the pressure gauge. Therefore, it becomes possible to use an inexpensive normal pressure gauge as a protection facility.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention, which is an improvement of the oil rotary vacuum pump of FIG. 3 described above. In FIG. 1, elements that are substantially the same as the elements described in FIG. 3 are assigned the same reference numerals.

The pump body 1 of the oil rotary vacuum pump comprises a motor section 2 and a pump section 3. The motor unit 2 has a cooling fan 13 on its motor shaft 2a, and the cooling fan 13 suppresses the temperature rise of the pump body 1. Further, a protective device (not shown) such as a thermal relay or a fuse is attached to the input portion of the motor unit 3, and as for the burnout protection when the motor unit 2 is overheated or overheated, The operation is similar to the device.

Most of the pump section 3 is the oil tank case 3.
It is arranged in the oil 4 stored in a. In this embodiment, a two-stage pump unit is shown as an example, and the first pump chamber 5
And a second pump chamber 6. The first pump chamber 5 is provided with a first pump rotor 9a and a first pump vane 10a fixed thereto, and the second pump chamber 6 is provided with a second pump rotor 9b and a second pump fixed thereto. For vane 10
b is provided. The rotating shafts of the first pump rotor 9 a and the second pump rotor 9 b are the shaft 2 a of the motor unit 2.
Are linked to. The rotor and vane structures are well known and will not be described in detail here. In the pump unit 3, 8 is an intake port, and 11a to 11c are exhaust valves forming exhaust ports. 14a to 14c are exhaust valve pressing springs that apply a predetermined pressure to the exhaust valves 11a to 11c, and 7 is an oil pump that lubricates, vacuum seals, and radiates an appropriate amount of oil from the oil 4 stored in the oil tank case 3a. For the first pump chamber 5
And to the second pump chamber 6. Further, 12 is an exhaust port of the oil tank case 3a, 15a and 15b are gaskets, 16 is an oil meter, 17 is an oil inlet, and 18 is an oil outlet. In addition to the above configuration, a pressure detecting pipe 19 having an opening at one end arranged in the oil 4 is provided, and the opening extending at the other end is arranged outside the oil tank case 3a. A pressure gauge 20 is attached to the other end of the pipe 19. Pressure gauge 20
Is a conventional one that is usually commercially available. Specifically, for example, a semiconductor pressure sensor is used.

The basic operation of the oil rotary vacuum pump having the above structure is exactly the same as that of the oil rotary vacuum pump described with reference to FIG.

In the structure shown in FIG. 1, when the inside of the oil tank case 3a is in a pressurized state due to some reason such as clogging of the pipe at the end of the exhaust port 12, the oil tank case 2 is stored in the oil tank case 2. The oil 15 is also pressurized and its pressure rises, and the pressure gauge 20 detects the pressure rise in the oil tank case 3a through the pressure detection pipe 19. Therefore, a reference pressure is set in advance, the reference pressure is compared with the increased pressure, and when the detected pressure exceeds the reference pressure, a signal indicating an abnormality or a signal S1 for stopping protection of the oil rotary vacuum pump is issued. Is configured as follows. The configuration for generating the signal S1 can be provided in the pressure gauge as in the present embodiment, and the pressure gauge outputs the detected pressure signal and processes the pressure signal by an externally added device to produce the signal S1. Can also be configured to generate.

In the above, 1.5~3kg / cm ² in the range of about desirably at an absolute pressure as a reference pressure to be set, issues an abnormality signal, for example, 1.5 kg / cm ^2, 2k
The pump is configured to be protectively stopped at g / cm ² .

FIG. 2 shows a second embodiment of the present invention, which is an embodiment corresponding to the oil rotary vacuum pump described in FIG. As an element added to the configuration of the oil rotary vacuum pump described in FIG. 1, 21 is an inert gas purge inlet, 23 is a gas ballast inlet, 24 is an oil bubbler (meaning oil bubbler piping), and 24a is an oil bubbler. The inlet port 22 is an inert gas to be introduced. In this embodiment, since the oil bubbler 24 is already installed in the oil 4 in the oil tank case 3a, it is not necessary to newly provide the pressure detection pipe 19 as in the above embodiment. Therefore, it suffices that the oil bubbler 24 is provided with the pressure gauge 20 for detecting the pressure rising state described in the above-mentioned embodiment, and further provided with the protective contact or the like as in the case of the above-mentioned embodiment. At this time, when the inert gas 22 is not introduced from the oil bubbler 24, the oiler bubbler 24 may be used just like the pressure detection pipe 19. When the oil bubbler 24 is used and the inert gas 22 or the like is introduced from here, by installing the pressure gauge 20 on the line of the oil bubbler 24, the pressure gauge 20 corresponds to the internal pressure of the oil tank case 3a. This results in a protected output.

In the case of the second embodiment, the oil tank case 3
Since the pressure inside a, the pressure due to the weight of the oil, and the blowing pressure of the inert gas 22 are further added, the reference pressure for detecting with the pressure gauge 20 is set with the pressure detection pipe 19. Compared with the case of using it, it is better to raise it slightly, for example, an abnormal signal is emitted at 2 kg / cm ² and 3 kg / cm ^2.
The pump is configured to be protectively stopped at cm ² .

As described above, when the exhaust port piping is clogged or some abnormality occurs in the exhaust gas treatment equipment, etc., and the pressure in the oil tank case 3a of the oil rotary vacuum pump rises, it is immediately corrected. It is possible to detect and prevent the exhaust gas from leaking to the outside and the pump from being damaged.

In each of the above-mentioned embodiments, the two-stage pump has been described, but the one-stage pump can be constructed in exactly the same manner.

[0026]

As is apparent from the above description, according to the present invention, a pipe member having an open end is arranged in the oil stored in the oil tank case to extend to the outside, and a pressure gauge is further provided. Since the protection means is applied by the above, it is possible to detect the pressure increase in the oil tank case accurately and quickly,
Exhaust gas leakage accidents and pump damage accidents can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of an oil rotary vacuum pump according to the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the oil rotary vacuum pump according to the present invention.

FIG. 3 is a vertical sectional view showing a first configuration example of a conventional oil rotary vacuum pump.

FIG. 4 is a longitudinal sectional view showing a second configuration example of a conventional oil rotary vacuum pump.

FIG. 5 is a graph showing the relationship between the oil tank case internal pressure and the motor current value.

FIG. 6 is a graph showing the relationship between the internal pressure of the oil tank case and the temperature of the pump body.

[Explanation of symbols]

1 pump body 2 motor part 3 pump part 4 oil 5 first pump chamber 6 second pump chamber 7 oil pump 8 intake port 9a, 9b rotor 10a, 10b vane 12 exhaust port 13 cooling fan 19 pressure detection pipe 20 pressure gauge 21 non Active gas purge inlet 22 Inert gas 23 Gas ballast inlet 24 Oil bubbler (oil bubbler piping)

Claims (3)

[Claims] 1. In an oil rotary vacuum pump, a pipe member having an opening end below the oil surface in the oil tank case and extending from the oil tank case to the outside, and a pipe member attached to the pipe member in the oil tank case. A pressure abnormality detecting device for an oil rotary vacuum pump, comprising a pressure gauge for detecting pressure abnormality. 2. The pressure abnormality detecting device for an oil rotary vacuum pump according to claim 1, wherein an oil bubbler pipe is used for the pipe member. 3. The pressure abnormality detecting device for an oil rotary vacuum pump according to claim 1 or 2, wherein the reference pressure for detecting the pressure abnormality by the pressure gauge is set within a range of about 1.5 to 3 kg / cm ^2. A pressure abnormality detection device for an oil rotary vacuum pump.