JPS6213796A - Air cooling type turbo-molecular pump - Google Patents

Abstract

PURPOSE:To prevent occurrence of an accident, by providing an air cooling fan cooling an oil tank for cooling and a fan sensor for detecting rotational condition of the air cooling fan. CONSTITUTION:An oil tank 2 installed adjacently to the machine chamber B of a turbo-molecular pump body 1 is provided with an air cooling fan 3. The cooling fan 3 is provided with a fan sensor 11 for detecting rotational condition of a fan f. If the air cooling fan 3 gets out of order, the fan sensor 11 detects the abnormality and the discrimination circuit of an electric power supply unit gives warning in response to the output signal of the sensor 11 so that the abnormality can be perceived immediately.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an air-cooled turbomolecular pump.

L Prior Art] A turbo molecular pump uses a turbo mechanism consisting of rotor blades and stator 5 arranged alternately in a rotor chamber to mechanically blow out and exhaust gas molecules.
It is characterized by the ability to obtain high vacuum.

By the way, in this type of pump, the rotor drive shaft that rotates the rotor blades at high speed in the rotor chamber is supported by a bearing in the mechanical chamber of the pump body, which is separated from the rotor chamber, and the rotational driving force is generated by a built-in motor. The machine room is usually equipped with an oil tank to store the necessary oil. That is,
The required amount of oil is stored in the oil tank to serve as both lubricating oil and refrigerant for the bearings, and when the pump is operating, fresh oil is constantly supplied to the bearings from the oil tank to provide optimal lubrication. The oil overflowing from the bearing is returned to the tank through the machine room to remove the heat generated by the bearing and the motor, thereby preventing overheating in the machine room. In the case of an air-cooled turbomolecular pump, a fan attached to the oil tank is used to forcefully air-cool the tank to prevent the oil temperature in the tank from rising.

[Problems to be solved by the invention] However, in such an air-cooled turbo molecular pump, if the car's air-cooling fan does not operate effectively for some reason, the temperature of the oil in the tank will rise, and the temperature in the machine room will rise. The temperature of the fan will rise abnormally, causing problems such as seizure of the bearings, and if the fan continues to operate for a long time with the fan inactive, performance will deteriorate, such as the ultimate pressure decreasing.
In extreme cases, the bearings will burn out and the main body of the turbomolecular pump itself will become inoperable. Accidents like this are occurring in people living in Japan, and as a result, expensive turbomolecular pumps are forced to be disposed of and replaced, and in some cases, vacuum equipment in which a faulty turbomolecular pump is installed has to be replaced. This also causes the inconvenience of failure.

Looking at the causes of air-cooling fan failures that cause such accidents, for example, in addition to mechanical causes in which the fan is clogged with foreign matter and cannot rotate, there are also electrical system failures such as disconnections in the fan's power supply and 5'. The most troublesome cause of failure is the human-caused cause of forgetting to connect the fan cord to supply power to the air-cooling fan. The main unit is configured so that it can operate independently even without power being supplied to the air θ fan.)

However, regardless of the cause mentioned above, the most important thing is to be able to detect the abnormality as early as -4 if the air cooling fan is not working properly when the pump is operating. That's true. However, in the past, this type of turbomolecular pump did not have a separate means for detecting abnormalities in the air cooling fan, which made it impossible to prevent major accidents like the one described above from occurring. .

[Means for Solving the Problems] Focusing on such circumstances, the present invention aims to reliably prevent the occurrence of accidents in turbomolecular pumps caused by abnormalities in the air cooling fan, regardless of the cause of the failure. For this purpose, a turbo-molecular pump body, an oil tank that stores cooling oil that also serves as lubricating oil for the bearings of this turbo-molecular pump body, and an air cooling fan that cools this oil tank are provided.

The present invention provides an air-cooled turbomolecular pump characterized by comprising a fan sensor that detects the rotational state of the air-cooling fan.

[Function] If a device is equipped with such a fan sensor, if there is a malfunction in the air cooling fan, a system that inputs the output signal from the fan sensor to notify the abnormality or a turbo molecular pump body can be installed. It is also easy to adopt a system that automatically stops the operation of the turbomolecular pump, and thereby it is possible to reliably avoid failure of the turbomolecular pump due to an abnormality in the air cooling fan.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an air-cooled turbo-molecular pump according to the present invention, which includes a turbo-molecular pump body 1, an oil tank 2 connected to a machine room B of this body 1, and an air-cooling fan for cooling this tank 2. 3. The turbo molecular pump main body 1 has rotor blades 4a protruding from the outer circumferential surface of the rotor 4 arranged alternately with stators gt5a protruding from the inner circumferential surface of the stator 5 in the upper rotor chamber A.
On the other hand, motors 6a and 6b for rotationally driving the drive shaft 9 that rotates the rotor 4 at high speed are installed in the lower machine room B, and bearings are installed at two upper and lower locations in the machine room B. (Pole bearing) 7.8 supports the drive shaft 9 for free rotation.

An oil tank 2 for storing lubricating and cooling oil 0 is provided in connection with the machine room B, and the oil sucked up through the inside of the drive shaft 9 whose lower end is immersed in the tank 2 is pumped into the bearing 7. 8, and then passed through the machine room B and returned to the tank 2.

Furthermore, an air cooling fan 3 is attached to the lower end of the oil tank 2 together with a drive source (not shown), which cools the oil 0 in the tank z by applying air from a fan f to the outer wall surface of the oil tank 2. . Note that I is the intake port of this pump, and II is also the exhaust port.

The air-cooling fan 3 in the air-cooled turbomolecular pump having such a configuration is attached with a fan sensor 11 for detecting the rotational state of the fan f. In the illustrated example, the fan sensor 11 is of a type that directly detects a change in magnetic flux caused by the rotation of the fan f through a change in pulse voltage, and compares this with a set rotation speed to detect an abnormality. Shows when to use. However, in the air-cooled turbo molecular pump equipped with this fan sensor 11,
As shown in Fig. 2, the main body 1 and the air cooling fan 3 are connected to a separate power supply unit 12 through power supply lines a and b, as is the usual method, so that the necessary operating power is supplied manually. , this power supply unit 12 and fan sensor 11 are connected by two pairs of lines c and d. One line C is a power supply line that supplies the power necessary for the detection operation of the sensor 11, and the other line d is a power supply line that supplies the power necessary for the detection operation of the sensor 11.
This is a signal line that outputs a normal signal when the fan f is detected to be in a normal rotational state, and an abnormality signal when an abnormality is detected in the rotational state to the it source 2 nearer 1 and 12. In the power supply unit 12, when power is being sent from the supply line a to the turbomolecular pump main body l, that is, when it is detected that the main body l is in an operating state, a signal line d is connected to the power supply unit 12. Not only when the abnormal signal is being output to λ, but also when the
Or, if it is detected that continuity is interrupted in any one of C, an alarm @13 attached to this
It has a built-in discrimination circuit designed to issue an alarm.

With this configuration, for example, even if the air cooling fan 3 breaks down, the fan sensor 11 attached thereto will detect the abnormality, and in response to the output signal of the sensor 11, the power supply unit 12 can be identified. The circuit will signal an alarm, which can be detected immediately. In addition, the above alarm system not only alerts you when the air cooling fan 3 malfunctions, but also when you forget to connect the cord to the air cooling fan 3 or fan sensor 11, or if they are disconnected. However, even if the fan sensor 11 itself is out of order, an abnormality is notified in the same way. In other words, it notifies you not only when a failure actually occurs in the air cooling fan 3, but also all abnormalities that lead to non-cooling operation of the turbomolecular pump. Therefore, if an alarm occurs during operation, inspection is required. By doing so, repairing or replacing the necessary parts, and connecting the specified cords, it is possible to ensure normal air cooling operation at all times.

Although the above-described embodiment is a preferred example of the present invention, modifications can be made in the following points. First, the fan sensor attached to the air cooling fan does not necessarily have to be of the type that directly detects the rotation of the fan as in the embodiment. In addition, although the embodiment employs a system that issues an alarm by inputting the output signal of the fan sensor, it is also possible to go further and stop the operation of the turbomolecular pump body at the same time. Although it is preferable to configure the system by considering all the conditions that lead to non-air cooling operation as in the example, it is preferable to configure the system by taking into consideration all the conditions that lead to non-air cooling operation. Of course, it is also possible to adopt.

[Effects of the Invention] Since the present invention has the above-described configuration, it is possible that the oil tank may be operated incorrectly due to a failure of the air cooling fan, etc., and the oil tank is not cooled as necessary. Therefore, it is possible to reliably prevent accidents in which the performance of the turbomolecular pump deteriorates or breaks down.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of an air-cooled turbomolecular pump showing an embodiment of the present invention, and FIG. 2 is a schematic diagram showing an alarm system thereof. l-...turbo molecular pump body, 2...oil tank, 311...air cooling fan, 11...φ fan sensor, O
···oil.

Claims (1)

[Claims] A turbo molecular pump body, an oil tank that stores cooling oil that also serves as lubricating oil for the bearings of the turbo molecular pump body, an air cooling fan that cools this oil tank, and a fan sensor that detects the rotational state of this air cooling fan. An air-cooled turbomolecular pump characterized by: