JPS6118235Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an oil-less dry suction pump, and particularly to a sealing means for a rotor shaft.

The bearing of an oil-less rotary vane pump has a bearing 4 on the shaft 3 of the rotor 2, as shown in Fig. A bearing portion 5 that is supported apart from the pump body 1 is provided in a protruding manner on the pump body 1 . A bearing space 6 formed between the pump body 1 and the bearing 4 communicates with the outside air. For this reason, the pump has shaft 3 and pump body 1.
It leaks from the gap between the pump and the pump, but because the gap is small, the amount of leakage is small compared to the pump's capacity, so it is usually ignored. However, when a large amount of gas must be sampled in a closed loop, this pump may have to be used because other low-leakage pumps cannot provide the flow rate. If the sampling gas is toxic or the components of the sampling gas are affected when outside air is drawn in, it is necessary to suppress leakage from the bearing.

In such a case, the bearing space 6 shown in FIG.
If you simply block up the space, the pressure in this space becomes negative,
Bearing oil is sucked into the pump, causing the bearing to run out of oil and increasing rotary vane wear. Further, since the bearing part 5 is cooled by the flow of outside air caused by leaking from the gap between the pump body 1 and the shaft 3 through the bearing part space 6,
If the bearing space 6 is blocked, the temperature will rise by the amount that the flow of outside air is stopped. For the above reasons,
If the bearing space 6 is blocked, the pump cannot be operated continuously.

Therefore, conventionally, the bearing space 6 was not blocked, and the pump was surrounded by a hood, so that even if the sampling gas leaked, it would not spread to the surrounding area. Also, when this was done, the pump generated heat, so it was necessary to exhaust a large amount of air with a hood or install a cooling device to cool the inside of the box. In addition, if the sampling gas has a different component from air, or if there is a problem with suctioning oxygen from the air, it is necessary to fill the surrounding area with gas of the same composition, but it is also necessary to replenish the gas or reduce the surrounding pressure. There were various problems, such as the need to control the pressure to a level that did not affect the pump's performance, and this was accompanied by great difficulties in terms of cost and technology.

SUMMARY OF THE INVENTION An object of the present invention is to provide an oil-less dry suction pump equipped with a shaft sealing means that solves the above-mentioned problems. For this reason, in the present invention, the communication port to the outside air provided in the pair of bearings of the suction pump is blocked, and the communication port connected to the suction port of the suction pump is A shaft pipe with low pressure loss is provided, one end of which is branched and connected to the sampling pipe, the other end of which is branched and connected to the pair of bearings, and opens into the bearing space, supplying a portion of the sampling gas to the bearing space. This reduces the pressure drop in the bearing space and prevents bearing oil from being sucked into the pump. At the same time, the flow rate of leak gas that is sucked into the pump from the gap between the rotor shaft and the pump body is supplied from the shaft piping. The desired result was achieved by maintaining a sufficient size with sampling gas and keeping the bearing well cooled.

Embodiments of the present invention will be described below with reference to the drawings. Figures 2 and 3 show an embodiment of a shaft-sealed dry suction pump according to the present invention.
FIG. 2 is a sectional view showing the bearing part, and FIG. 3 is a system diagram showing the piping of the suction pump. Note that parts equivalent to those in FIG. 1 are given the same reference numerals and their explanations will be omitted.
As shown in FIG. 2, the communication port 7 of the bearing portion 5 to the atmosphere is hermetically sealed with a sealing plate 8. And the third
As shown in the figure, one end of the sampling pipe 9 connected to the suction port of the suction pump 1 is connected to a sampling pipe 9 upstream of equipment 10 such as a measuring device interposed therebetween, and the other end is branched to connect the pair of sampling pipes 9 to A shaft pipe 11 is provided which is connected to the bearing part 5 and opens into the bearing part space 6 as shown in FIG.

In the suction pump of the embodiment of the present invention configured as described above, the pressure on the discharge side of the pump is slightly higher than atmospheric pressure, but the pressure on the suction side of the pump is -20
Since the pressure is negative (cmHg), most of the leakage from the gap between the pump body 1 and the shaft 3 is sucked out, and therefore the bearing space 6 that is blocked by the sealing plate 8 is There is negative pressure. The pressure of the sampling gas in the sampling pipe 9 at the point where the shaft pipe 11 branches is approximately equal to atmospheric pressure because it is just before pressure loss occurs due to the device 10. Therefore, the sampling gas flows into the bearing space 6 due to the pressure difference between the pressure of the sampling gas at the branch point and the negative pressure in the bearing space 6, and the pressure there can be prevented from becoming too negative. Pump body 1 within bearing space 6
The amount of suction leakage from the gap between the shaft 3 and the shaft 3 is small compared to the pump capacity, so by appropriately selecting the relationship between the length and thickness of the shaft piping 11, the pressure loss between the branch point and the bearing space 6 can be reduced. is several tens of mmH ₂ O, which is sufficiently small compared to the pressure difference between the inside of the pump and the bearing space 6.
It can be: In this way, the leak gas sucked into the pump through the gap is sufficiently secured by the sampling gas flowing in from the shaft pipe 11, and a state similar to the conventional state when communicating with outside air can be maintained. Can be done. Therefore, it is possible to prevent the temperature of the bearing 4 from rising and from running out of oil, so that the pump can be operated continuously without accelerating deterioration of the bearing. Furthermore, since the shaft is sealed with sampling gas, maintenance such as gas replenishment is not required. Moreover, since it is sufficient to simply provide the shaft piping 11 around the pump without requiring any special equipment, space and cost can be reduced. Furthermore, since outside air is not sucked into the closed loop, there is no effect on the sampling gas. Furthermore, since the bearing space 6 is sealed from the outside air, leakage of the sampling gas to the surroundings is completely prevented.

In addition, when the pressure of the sampling gas is higher than atmospheric pressure, a pressure regulating valve may be provided in the shaft pipe 11 to reduce the pressure to atmospheric pressure. Furthermore, if the pressure of the sampling gas is lower than atmospheric pressure, a small pump may be provided in the shaft piping to increase the pressure to atmospheric pressure.

As detailed above, according to the present invention, the bearing part is sealed and the gas inside the pump does not leak to the outside.
In addition, a portion of the sampling gas sucked in by the pump is used to sufficiently cool the bearing, which prevents the bearing from rising in temperature and running out of oil, and since outside air is not sucked into the closed loop, it does not affect the sampling gas. It is possible to provide a shaft-sealed dry suction pump that does not cause any adverse effects.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of the bearing part of a conventional oil-less dry suction pump, and FIG. 2 is a cross-sectional view showing the structure of the bearing part of a shaft-sealed dry suction pump according to an embodiment of the present invention. FIG. 3 is a system diagram showing the piping of the shaft-sealed dry suction pump. DESCRIPTION OF SYMBOLS 1... Pump body, 2... Rotor, 3... Rotor shaft, 4... Bearing, 5... Bearing part, 6... Bearing space, 7... Communication port, 8... Sealing plate, 9 ...Sampling piping, 10...Equipment, 11...Shaft piping.

Claims (1)

[Scope of utility model registration request] A sealing plate that seals each communication port with the outside air provided in a pair of bearing parts that protrude from the pump body and support the rotor shaft bearing at a distance from the pump body; A shaft portion with low pressure loss that has one end branched and connected to the sampling pipe upstream of the equipment intervening in the sampling pipe connected to the port, the other end branched and connected to the pair of bearing parts, and opens into the bearing space. and supplying the sampling gas to the bearing space based on the pressure difference between the pressure of the sampling gas in the shaft pipe and the pressure in the bearing space to alleviate the pressure drop in the bearing space. In addition to preventing bearing oil from being sucked into the pump, the flow rate of leak gas sucked into the pump from the gap between the rotor shaft and the pump body is made to a sufficient level by the sampling gas supplied from the shaft piping. A shaft-sealed dry suction pump that maintains good bearing cooling.