JPH07127748A - Shaft sealing method for rotary valve - Google Patents

Abstract

PURPOSE:To prevent foreign matter and noise from producing by providing a gas feed hole to a space for filling shaft seal material, making an inner clearance larger slightly than an outer clearance, and blowing the fed gas to a valve through the inner clearance. CONSTITUTION:In a rotary valve, a gas feed hole 3 is drilled to a space for filling shaft seal material 4 which is located adjacent to a gland 2 around a shaft 1. Also air, nitrogen gas, etc., fed through the gas feed hole 3 made to flow into a product side, i.e., into a valve through an inner clearance 5. By this, powder and granular material is prevented from entering the gland 2, i.e., the inner clearance 5. Then the inner clearance 5 is made larger slightly than an outer clearance 6. and the outer clearance 6 is reduced as small as possible. In addition, packings 7 and 8 are the gas sealing material of the shaft 1. Thus production of foreign matter and noise at the shaft seal part can be eliminated, and also repair is not required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary valve shaft sealing method. More specifically, the present invention relates to a rotary valve shaft sealing method in which no foreign matter is mixed into a product, abnormal noise is not generated, and repair is unnecessary.

[0002]

2. Description of the Related Art A rotary valve is a valve used in a place where a sealing property and a fixed amount of supply are required, and is used for handling an inorganic or organic powder or granular material under various conditions. Fluororesin-impregnated asbestos lattice knit packing is used as the shaft sealing material for rotary valves.Since these are relatively fragile, they are used by coating them with a lubricating agent such as grease to impart wear resistance. ing. However, it is not so effective at high temperatures, and it becomes one of the causes of becoming foreign matter and contaminating products. In particular, when a resin powder such as a polycarbonate resin is used as the powder and the powder flows between the shaft sealing material and the shaft at high temperature, it is melted and deteriorated by frictional heat to promote wear, and Metal powder, shaft sealing material powder, altered resin powder, etc. are mixed in the product, and the contaminated product has a markedly reduced commercial value.
It cannot be used for precision optical products such as films, optical fibers and lenses. Further, when the powder and granules flow into the gap of the ground, not only foreign matter is generated but also a high-pitched noise is generated, which is one of the noises. Frequent repair is required to prevent such foreign matter and noise. The standard of repair is determined by the occurrence of abnormal noise, leakage of powder and granules to the outside, contamination of powder and granules, etc.
If these abnormalities are left unattended and the operation is continued as it is, the drive motor of the rotary valve is stopped or burned. Even if the shaft sealing material is renewed due to an abnormality, the abnormality often reoccurs frequently, and the labor cost required for this and the loss due to the process stoppage are enormous, and improvement is desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a shaft sealing method for a rotary valve, which does not generate foreign matter or noise in the shaft sealing portion and does not require repair.

As a result of various investigations aimed at achieving the above object, the inventor of the present invention has succeeded in eliminating the shaft sealing material, which is a major cause of foreign matter, by blowing air into the space filled with the shaft sealing material instead of the shaft sealing material. The present invention has been completed by researching that powder particles can be prevented from flowing into the gland portion without using them.

[0005]

According to the present invention, a gas supply hole is provided in a space for filling a shaft seal material of a rotary valve, and a gap inside the opening of the gas supply hole is slightly larger than a gap outside the gas supply gas. A method of sealing a shaft of a rotary valve, characterized in that gas supplied from a supply hole is blown into the valve through an inner gap.

The present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a gland portion of a rotary valve. In the figure, 1 is a shaft, 2 is a gland, 3 is a gas supply hole, 4 is a space for filling a shaft sealing material, 5 is an inner gap, and 6 is an outer gap. , 7 and 8 are packings.

The gas supply hole 3 is provided for blowing gas into the space 4 that has been conventionally filled with the shaft sealing material, and can be provided at any position where gas can be blown into the space 4, and one gas supply hole 3 can be provided. The gas blown from the gas supply holes 3 flows through the inner gap 5 to the product side, that is, the inside of the valve, and prevents the granular material from flowing into the ground part, that is, the inner gap 5. To do.

The gas used here may be any gas as long as it does not adversely affect the product powder or granules such as air, nitrogen gas, carbon dioxide gas or the rotary valve. Particularly, a clean gas from which foreign matters and oils and fats are removed by filtration or the like is preferable. The flow velocity of the gas may be higher than that which can prevent the inflow of the granular material into the gap 5 inside, and it is preferable to blow the gas so that the flow velocity in the gap 5 inside is usually about 4 m / sec.

The inner gap 5 must be slightly larger than the outer gap 6. In particular, the outer gap 6 should be as small as possible, and is preferably 0.1 mm or less, and the inner gap 5 is preferably about 0.5 mm. The packings 7 and 8 are shaft gas sealing materials, and are preferably a material having lubricity, wear resistance, and heat resistance, and may be an inorganic material, an organic material, or a combination of these materials. For example, Teflon is a good example. one of.

[0010]

EXAMPLES The present invention will be further described below with reference to examples. The foreign matter in the product was inspected by dissolving 100 g of the polycarbonate resin powder in 400 g of methylene chloride, suction-filtering with a filter medium having an opening of 50 μm, and visually counting the foreign matter on the filter medium.

[0011]

Example 1 In a process of continuously receiving dried 145 ° C. polycarbonate resin powder particles into a storage tank equipped with a rotary valve having a shaft diameter of 45 mm, a gap 5 on the inner side of the gland portion of the rotary valve is 0.5 mm and an outer side. The gap 6 is adjusted to 0.1 mm, the packing 7 is a Teflon plate with a thickness of 1 mm, and the dehumidified air filtered from the gas supply hole 3 is 2 m ³ /
It was blown for a time (flow velocity 4 m / sec in the inner gap 5). Table 1 shows the number of foreign matters, the number of abnormal noises, and the number of repairs in 1 kg of the polycarbonate resin powder particles on the 3rd day, 1st month, and 1st year after the start of operation.

[0012]

[Table 1]

[0013]

[Comparative Example 1] Instead of the air seal of the gland portion of the rotary valve, a fluororesin VALFLON-impregnated asbestos lattice knit packing was filled and continuous operation was carried out in the same manner as in Example 1, and the results are shown in Table 2.

[0014]

[Table 2]

[0015]

EFFECTS OF THE INVENTION According to the present invention, the generation of foreign matter from the shaft sealing portion of the rotary valve is eliminated, the contamination of the product is remarkably suppressed, the repair is required less than once a year, and the opportunity loss due to the stop of the rotary valve is lost. Furthermore, the effect produced by the rotary valve is exceptional, as it produces a comfortable working environment without the abnormal noise of the rotary valve.

[Brief description of drawings]

FIG. 1 is a sectional view of a gland portion of a rotary valve of the present invention.

[Explanation of symbols]

 1 Axis 2 Ground 3 Gas Supply Hole 4 Space for Filling Shaft Sealing Material 5 Inner Gap 6 Outer Gap 7, 8 Packing

Claims (1)

[Claims] 1. A gas supply hole is provided in a space for filling a shaft sealing material of a rotary valve, a gap inside the opening of the gas supply hole is made slightly larger than a gap outside, and the gas supplied from the gas supply hole is inside. A method for sealing a shaft of a rotary valve, characterized in that the air is blown into the valve through the gap.