JPS5824665A - Special valve - Google Patents

Abstract

PURPOSE:To prevent leakage from a valve applied to the gas purger of a tire vulcanizer or the like, by setting two passages different in inside diameter, a valve spindle provided in one passage and a spring for urging the spindle, in a prescribed relationship. CONSTITUTION:A special valve 11 has an L-shaped passage 18. A flexible hose 20 for gas purging is connected to the inlet port 19 of the lower part 18a of the passage 18. A valve spindle 21 is fitted in the upper part 18b (first passage) of the passage 18 and maintained in the closed position by a helical spring 26. A communication hole (second passage) 22 is provided to connect the parts 18a, 18b of the passage 18 to each other. The inside diameter A of the first passage 18b, the inside diameter B of the second passage 22, the force fs of the helical spring 26, positive pressure PI acting to the first passage and negative pressure PV acting to the second passage 22 are related to one another as fs=piA<2>/4PI and fs+piB<2>/4PV<piA<2>/4PI.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special valve that normally closes by overcoming positive pressure and opens by defeating the minimum necessary negative pressure, such as a gas venting device in a tire vulcanizer with a bladder set. It can be suitably adopted for such applications.

That is, the present invention provides a first passage having an inner diameter A, a second passage having an inner diameter B, a valve spindle disposed in the second passage and having a smaller diameter than the inner diameter B and a larger diameter than the inner diameter A, and a spring for each valve spindle. When a positive pressure pi acts on the first passage and a negative pressure PV acts on the second passage, f, -πA/4PI fs+gB2/4 PV < The present invention provides a special valve characterized by satisfying the iA2/4 PI relationship.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments in which the present invention is applied to a gas venting device in a tire vulcanizer will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the upper ring 3 attached to the center post 2 with a clip 9 has a bladder 8 held therein by a bladder presser 10, while the lower surface of the outer periphery of the upper ring 3 has a
A special valve 11 is screwed on with the inlet 19 directed toward the outer circumference, and a nipple 12 that penetrates the bladder holder 10 from above is connected to the upper ring 3 in correspondence with the special valve 11.
The special valve 11 and nipple 12 form a gas vent passage 13.

As shown in detail in FIG. 2, the special valve 11 has an inverted-shaped passage 18, and a flexible degassing hose 20 can be connected to the inlet 19 of the lower passage 18a. On the other hand, in the upper passage 18b, a valve spindle 21 is fitted into the passage 18b with a gas vent gap therebetween, and a communication hole 22 is provided to communicate the passage 18a and the passage 18b. A coil spring 26 is compressed between the sleeve screw 25 and the top portion 21 to maintain the valve spindle 21 in the closed position at all times.

The opening and closing force of the valve spindle 21 is set by adjusting the biasing force of the coil spring 26 depending on the screwing position of the sleeve screw 25.

The spring force fs of the coil spring 26 overcomes the pressure PI in the bladder 8 and closes the communication hole 22 by the valve spindle 21, while it overcomes the suction force PV of the ejector 38, which will be described later, and opens the communication hole 22. In order to
The relationship between the inner diameter B of the upper passage 18b and the inner diameter A of the communication hole 22 is made as large as possible.

That is, f, ) - P I 4 , the gas is absorbed by making the valve spindle 21 float by unbalancing pI and PV at the minimum necessary degree of vacuum.

The nipple 17 on the side of the center post 2 and the nipple 12 of the upper ring 3 are connected by a conduit 27, and the nipple 17 of the center post 2 is connected to the suction mechanism 42 through the opening 41 of the top ring 29 via the conduit 31. The suction mechanism 42 is connected to high pressure water (3
~21 Kg/ctA) to the ejector 38,
It is connected via a switching valve 39. Vacuum pumps can be used in addition to water pumps. When using the special valve 11, it is especially necessary to use a water filter 2 or a vacuum pump line in the piping system.

If the degassing device in a tire vulcanizer is configured as described above, when supplying and discharging a vulcanizing medium such as hot water, steam, gas, or cooling water into the bladder 8, the valve spindle 21 of the special valve 11 is connected to the coil. The biasing force of the spring 26 overcomes the positive pressure inside the bladder 8 and closes the communication hole 22, so the vulcanizing medium is shut out inside the bladder 8, so the bladder
There is no longer any risk of steam or gas leaking from external piping.

Next, during the degassing process in the bladder 8 (that is, when switching from the gas process to the cooling water process), when the switching valves 37 and 39 are opened to supply high-pressure water to the ejector 38, the ejector 3
Due to the suction power of 8, degassing hose 20 → special valve 1
1 → Nipple 12 → Conduit 27 → Nipple 17 → Piping 31
→ Gas can be quickly and sufficiently removed through the switching valve 39, and heating and cooling of the tire can be made uniform, so that insufficient vulcanization can be prevented in advance.

That is, the valve spindle 21 of the special valve 11 opens the communication hole 22 under the minimum necessary negative pressure of the ejector 38.

As is clear from the above description, the present invention is based on the first aspect. This is a special valve with a specific relationship between the second passage, the valve spindle, and the spring member, so if it is used in a gas venting device in a tire vulcanizer, steam or gas will not constantly pass through the bladder external piping. There is no risk of leakage, and the placement conditions can be made that much milder.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a gas venting device in a tire vulcanizer.
FIG. 2 is a sectional view of the special valve. 11... Special valve, 18... Passage, 18a...
Lower passage, '18 b... Upper passage (second passage),
19... Inlet, 21... Valve spindle, 22...
...Communication hole (first passage), 2s...Sleeve screw, 2
6... Coil Ha. Patent applicant: Sumitomo Rubber Industries, Ltd.
Patent attorney Aoyama Aoyama and 2 others Figure 2 180 18

Claims (1)

[Claims] (1) A first passage with an inner diameter A, a second passage with an inner diameter B, and a second passage with an inner diameter A.
The valve spindle is disposed in the passage and has a diameter smaller than the inner diameter B and larger than the inner diameter A, and a spring member that biases the valve spindle with a spring force f to close the first passage. A special valve characterized in that, when pressure PI and negative pressure PV act on the second passage, fs-=yrA/4 PI f5+πB2/4 PV (rA274 PI).