JPH0449421Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gasket that prevents gas or liquid from leaking from around a needle valve rod that slides back and forth, and particularly for a gasket with an outer diameter of 2 to 3 mm such as in a spray gun.
This invention relates to a packing device with a novel configuration suitable for use on valve stems.

[Prior Art] Conventionally, this type of needle valve gasket is made of a cylinder made of leather, tetrafluoride resin, or oil-impregnated asbestos with a thickness of several millimeters, or a cylinder made by laminating flat gaskets 1, as shown in Fig. 3. A type of paper was used.

[Problems to be solved by the invention] However, these gaskets lack durability compared to other parts of the spray gun, and this was considered to be one of the problems that should be improved.

In particular, when used for painting, the performance of the seal is influenced by the properties of the paint used. In other words, the disadvantages are that leather packings become hard due to absorption of moisture and volatile solvents, and that polyfluoride resins wear out quickly.

In addition, material improvements have been made to tetrafluoride resin sealing materials, which have improved wear resistance by adding fillers to tetrafluoride resins that are resistant to solvents and have a low coefficient of friction. However, the conventional packing structure still had problems with durability.

[Purpose of the invention] The purpose of the invention is to solve these problems, improve the durability of the packing, eliminate the increase in sliding resistance, and facilitate maintenance.

[Structure of the invention] The present invention has a needle valve rod with an outer diameter of several millimeters penetrating a part of the spray gun body, and prevents fluid from leaking between the spray gun body and the needle valve rod. In a packing device for a needle valve stem, which is equipped with a fluid seal to prevent fluid leakage, a thin plate-like flat packing is constructed by laminating a filler-containing tetrafluoride resin material having abrasion resistance and an elastic material having rubber elasticity. The rubber elastic material side of the thin plate-like flat packing is placed on the high pressure side and the tetrafluoride resin material is placed on the low pressure side, and further, the inner diameter part of the thin plate-like flat packing is reciprocated through the inner diameter part. The diameter is smaller than the outer diameter of the needle valve stem, and the inner diameter part of the thin plate-shaped flat packing is bent toward the high pressure side to form a lip part, and an escape groove for the lip part to enter is formed in the spray gun body, Furthermore, the needle valve stem packing device is constructed by attaching a packing pusher to the spray gun body, which allows the outer diameter side of the thin plate packing to be tightened from the low pressure side.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which a needle valve stem 2 is provided through a part of a spray gun body 3, and the spray gun body 3 and needle valve stem 2 are connected. A gasket 4 is provided in between to prevent paint from flowing out from the paint side inside the spray gun body 3 to the outside of the spray gun body 3. The packing 4 uses a thin plate-like flat packing made by pasting together a filler-containing tetrafluoride resin material 5 having wear resistance and an elastic material 6 having rubber elasticity. Paint side 1, which is the high pressure side
1 and is incorporated into the spray gun body 3. The thickness of the packing in this example is 0.5 mm, which is much thinner than the several millimeters of conventional packing. The outer diameter side of the gasket is closely fixed between the spray gun body 3 by a gasket pusher 7, and the inner diameter of the center part of the gasket 4 is smaller than the needle valve rod 2 to be inserted, so that the needle is connected to the low-pressure side 12. By inserting the valve stem 2, the inner diameter portion is bent and a lip portion 8 is formed on the high pressure side. A relief groove 9 is formed at the location where this lip portion 8 corresponds to the spray gun body 3, so that the lip portion 8 where the inner diameter portion of the thin flat packing 4 bends is formed in the relief groove 9 of the spray gun body. Get into it. Since this slightly curved lip part is approximately the same thickness as the packing 4, the inner diameter of the center of the packing 4 is smaller than the outer diameter of the needle valve stem 2 by about twice the plate thickness. It's summery. As a result, only the abrasion-resistant filler-containing tetrafluoride resin material 5 of the packing 4 comes into contact with and slides on the needle valve stem 2, maintaining sealing performance and reducing sliding resistance. A decrease is expected.

In addition, a relief groove 9 is formed at a portion of the lip portion 8 corresponding to the spray gun body 3, and when the lip portion 8 enters the relief groove 9, the elastic force of the elastic material having rubber elasticity allows Since it has the function of returning the tetrafluoride resin material 5 to the needle valve stem 2 side, when the paint on the high pressure side is applied to the lip part 8 of the seal 4, this high pressure paint causes the seal 4 to
The lip portion 8 is pressed against the needle valve stem 2 toward the other low pressure side and moves in the axial direction, thereby ensuring a seal between the reciprocating needle valve stem 2 and the inner diameter of the packing 4. This prevents the high-pressure paint from leaking from the axial direction, and stabilizes the sealing effect of the lip portion 8.

In the embodiment shown in FIG. 2, two sets of unit packings 4 are used, and a washer 10 is provided between each packing. In this case, the washer 10 corresponding to the lip portion 8 is also provided with an escape groove 9 for the same reason as described above.

[Effect of the invention] From the above structure, the reciprocating needle valve rod 2 and the inner diameter part of the packing 4 slide closely, are pressed and deformed toward the low pressure side by the high-pressure paint, and slide while maintaining a close state. The lip portion 8 reliably prevents leakage. Moreover, the one that slides directly with the needle valve stem 2 is
Only the filler-containing tetrafluoride resin material 5 having wear resistance is used, and since the resin material 5 is a thin plate and has low sliding resistance due to its material, the needle valve stem 2 can be lightly reciprocated in the axial direction. I can do it.

In addition, the elastic material 6 having rubber elasticity does not come into direct contact with the needle valve stem 2, but is pressed from the high pressure side so that the filler-containing tetrafluoride resin material 5 having wear resistance is always in close contact with the needle valve stem 2. By doing so, it is possible to maintain a stable leak prevention effect over a long period of time. According to the embodiment, conventionally, it was necessary to tighten the needle valve 2 with the seal pusher 7 after 200,000 to 400,000 reciprocating operations of the needle valve stem 2, but the present proposal
Can be used continuously without retightening even after 10,000 reciprocating operations, and the needle valve stem 2 that is in contact with the 4 parts of the seal
Almost no wear was observed.

As described above, according to the present invention, durability and stability are improved compared to conventional needle valve stem packings, and maintenance is facilitated. In addition, since the sliding resistance of the needle valve stem due to the gasket is small, the needle valve stem can be moved toward the paint side, reducing the load on the valve spring (not shown) that stops paint spouting, making it possible for paint spouting operations. At the same time, the operation of moving the needle valve stem toward the side opposite to the paint becomes easier, and therefore, the fatigue caused when moving the needle valve stem is reduced, and many other effects can be obtained.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing each embodiment of the needle valve rod packing device of the present invention, and FIG. 3 is a sectional view showing an example of a conventional needle valve packing. 2...Needle valve stem, 4...Putskin, 7...
Push the seal, 8... Lip part, 9... Relief groove,
10...Washer.

Claims (1)

[Scope of utility model registration request] A needle valve stem 2 with an outer diameter of several millimeters is provided to penetrate a part of the spray gun body 3, and a fluid seal is provided to prevent fluid from leaking between the spray gun body 3 and the needle valve stem 2. In the needle valve stem packing device, a thin plate-like flat packing 4 is constructed by laminating a filler-containing tetrafluoride resin material 5 having abrasion resistance and an elastic material 6 having rubber elasticity. The thin plate-shaped flat packing 4 is arranged so that the rubber elastic material 6 side is on the high pressure side and the tetrafluoride resin material 5 side is on the low pressure side, and the inner diameter part of the thin plate-shaped flat packing 4 is moved back and forth between the inner diameter parts. The diameter is smaller than the outer diameter of the needle valve rod 2 that passes through the needle valve rod 2, and the inner diameter of the thin plate-shaped flat packing 4 is bent toward the high pressure side to form a lip portion 8, and an escape groove 9 for the lip portion 8 to enter. is formed on the spray gun body 3, and a seal pusher 1 is attached to the spray gun body 3 to allow the outer diameter side of the thin plate-like seal 4 to be tightened from the low pressure side.