JPS60228937A - Dust counter - Google Patents

Abstract

PURPOSE:To suppress the generation of dust from a dust measuring apparatus, by sending cooling air in order to cool the vacuum pump, which generates heat, used in a dust measuring apparatus and exhausting the same through a filter. CONSTITUTION:Air 2 to be measured is sent to a dust detection part 3 while sucked by a vacuum pump 4 to detect dust in air. Next, air is sent to a filter 5 from the pump 4 to remove dust with a particle size of 0.1mum or more and a part of the filtered air is sent to the detection part 3 as sheath air and the remainder is exhausted from an exhaust part 9. At this time, cooling air 10 is introduced in order to cool the pump 4 generating heat to cool the same and exhausted from a fan 11 through a filter 12. Because cooling air is exhausted through the filter, the contamination of air outside the dust measuring apparatus is prevented and this apparatus can be effectively used in IC, drug preparing fields and a medical field.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a measuring instrument for measuring cleanliness, and is particularly suitable for measuring dust in the air.

Conventional configurations and their problems In recent years, a highly clean, sterile, and dust-free environment has been required in many fields such as the IC semiconductor industry, pharmaceutical industry, and medical care. Against this background, dust counters play a very important role in determining cleanliness.

The conventional dust counter as described above will be explained below with reference to the drawings.

FIG. 1 shows a flow sheet of a conventional example. Main body 1, sample air suction line 2, optical system detection section 3, and detection section 3
a vacuum pump 4 for supplying sample air to the sample air; a membrane filter 6 for removing part of the task of the sample air taken in; and a membrane filter 6 for removing dust and purifying the air. A sheath air line 6 that supplies sheath air of the air to be measured to the detection unit 3, a flow rate adjustment valve 7 for adjusting the amount of sample air, a flow meter 8 for checking the flow rate adjustment, and an exhaust line 9. ,
A cooling air intake port 1o inside the device provided in the main body 1;
Cooling fan 11 that takes in cooling air and exhausts it to the outside of the device
It is well structured.

The operation of the dust counter configured as described above will be explained below.

Air to be measured is sent to an optical system dust detection section 3 by a vacuum pump 4 through an air suction line 2 to be measured which partially exits from the main body 1 to the outside of the apparatus. At this time, the sucked air to be measured is purified by a pleated membrane filter 5 that removes 0.1 micron dust, and a part of it is used as sheath air of the air to be measured by the vacuum pump 4. The remaining particles supplied to the detection section 3 are discharged from the discharge port 9. The amount released is determined by looking at the flowmeter 8.
This is done with a flow rate control valve 7.

Also vacuum pump 4. The heat generated from the optical system dust detection section 3 passes through the cooling air intake port 10 provided in the main body 1.
The cooling air drawn into the device by the cooling fan 11 is cooled and discharged to the outside of the device.

However, with the above configuration, when measuring dust, the exhaust emitted from the cooling fan 11 contains a very large amount of dust, and the dust counter itself becomes a source of dust, making it impossible to measure dust accurately. There were drawbacks.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention aims to suppress dust generation from a dust counter.

Structure of the Invention To achieve this object, the dust counter of the present invention includes an optical dust detection section, a vacuum pump for supplying sample air consisting of sheath air and purge air to the detection section, and a vacuum pump for supplying the sheath air to the detection section. A membrane filter to keep it clean, a flowmeter and a flow rate adjustment valve to control the amount of sample air, a cooling fan to cool the vacuum pump, and dust inside the device from the exhaust port of the cooling fan. It consists of a HEPA filter to prevent the air from being released into the atmosphere.

With this configuration, the dust inside the device, which was conventionally released into the atmosphere from the exhaust port of the cooling fan, is completely captured by the HEPA filter attached to the exhaust port, preventing dust contamination of the atmosphere. .

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a flow sheet of an embodiment of the present invention.

In Fig. 2, 1 is the main body, 2 is a suction line for sample air, 3 is a dust detection section of the optical system, and 4 is a vacuum pump 5 for supplying sample air to the dust detection section. A membrane filter 16 for removing dust from the membrane filter 5 is a sheath airline line that supplies the clean air after removing dust from the membrane filter 5 to the detection section 3 as sheath air of the air to be measured, and 7 is a sample air volume. 8 is a flow meter for checking the flow rate adjustment; 9 is an exhaust line; 10 is a cooling air intake port 11 inside the device provided in the main body 1; This is a cooling fan for taking in cooling air and supplying it to the HEPA filter 12 for removing dust in exhaust air.

The operation of the dust counter configured as above will be explained below. Note that explanations of parts that overlap with the conventional example have been omitted.

The heat generated by the vacuum pump 4 and the dust detection part 3 of the optical system is cooled by the cooling air taken into the device by the cooling fan 11, and the cooling air passes through a HEPA filter installed immediately after the cooling fan 11. By passing through the air, the dust is removed and released as warm exhaust gas.

The reduction in the dust level in the exhaust gas in this example is shown in FIG.

As described above, according to this embodiment, the dust level of the air used for cooling discharged from the apparatus can be reduced to about 150 times by passing it through the HEPA filter 12.

Effects of the Invention As described above, the present invention has a practical advantage in that by attaching a HEPA filter to the cooling air exhaust port, it is possible to prevent the dust inside the device body from being discharged to the outside of the device together with the cooling air and contaminating the atmosphere. The effects are huge.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of a conventional example, FIG. 2 is a flow sheet of an embodiment of the present invention, and FIG. 3 is a graph of the results of an effect experiment of an embodiment of the present invention. 3...Dust detection section, 4...Vacuum pump, 6...Membrane filter-17...
・Flow rate adjustment ill half, 8...Flowmeter, 11
...Cooling fan, 12...HE PA filter (filter). Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] A dust detection section, a vacuum pump for supplying sample air consisting of sheath air and purge air to the dust detection section, a membrane filter for keeping the sheath air clean, and an amount of the sample air. with a flow meter and flow control valve to control the flow rate. A dust counter comprising a cooling fan that cools the vacuum pump and a filter attached to an exhaust port of the cooling fan.