JPS639150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball valve, and particularly to a so-called metal touch type ball valve in which a metal seat ring is brought into contact with a ball.

Since metal touch type ball valves are used in high-temperature fluid flow paths, they have a structure that allows the seat ring to slide freely according to the thermal expansion of the ball. Therefore, it is necessary to provide a sealing structure between the seat ring and the valve body. The seal structure needs to be an elastic seal, so-called soft touch, so that the seat ring can slide smoothly following the thermal expansion of the ball.
Conventionally, therefore, a rubber O-ring is used when the fluid temperature is below 200°C, and a cloth gland packing is used when it exceeds that temperature.

Therefore, conventionally, two types were required, and it was necessary to use one depending on the temperature.

The present invention aims to eliminate the above-mentioned inconvenience and provide a ball valve that can be applied over a wide range of temperatures.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The embodiment shown in FIG. 1 is basically a conventional metal touch type ball valve, in which a metal seat ring 3 is brought into contact with a ball 2 built into a body 1. The seat ring 3 includes an inner ring 3a and an outer ring 3 that contact the ball 2.
b, and both are integrally connected by a screw joint 4 and inserted into an opening in the body 1. A recessed step 5 (see FIG. 2) is formed on the outer periphery of the inner ring 3a in proximity to the threaded joint 4, and this step 5 and the outer ring 3
A seal ring 6, which will be described later, is placed in the recess formed between b.
is intervened.

A sheet retainer ring 7 is screwed into the open end of the body 1, and a disc spring 8 is interposed between the retainer ring 7 and the outer ring 3b, and the tip of the protrusion 9 of the outer ring 3b and its The presser ring 7 fitted with the protrusion 9 is inserted into the recess 10.
An appropriate gap a is provided between the two.

Therefore, when the ball 2 thermally expands, the seat ring 3 can slide within the gap a while compressing the disc spring 8.

Now, as shown in FIG. 3 as a partially enlarged view of the seal ring 6, the seal ring 6 has an endless spiral spring 12 tightly inserted into a highly ductile metal covering 11. A slit 13 is formed on the outer peripheral surface of the covering 11 over the entire circumference. When a force is applied to the seal ring 6 in the direction of increasing or decreasing its diameter, the helical spring 12
The cover 11 has a flexible property that plastic deformation occurs due to the deformation of the cover 11. (For example, "Erichofrex" manufactured by Sephiraque in France) Since the seal ring 6 used in this invention has the above-mentioned properties, the helical spring 12 is compressed around the outer periphery of the seat ring 3. By pressing the seat ring 3 against the inner periphery of the body 1, a seal is formed between the seat ring 3 and the body 1.

In FIG. 2, the seal ring 6 is inserted so that the slit 13 faces inside (towards the ball), but it may be inserted so that it faces outside.

Furthermore, the configuration of the body 1 and seat ring 3 is as follows:
As shown in FIGS. 4 and 5, the sheet holding ring 7 described above may be omitted, and the outer ring 3b and disc spring 8 may be directly opposed to the body 1.

The ball valve of the present invention is constructed as described above. At room temperature, the seal ring 6 is interposed between the seat ring 3 and the body 1 with the helical spring 12 compressed, and the helical spring 12 is compressed. Due to its elasticity, it comes into elastic pressure contact with the inner surface of the body 1. Therefore, when the ball 2 thermally expands, the seat ring 3 can follow the expansion and slide smoothly. Moreover, since the seal ring 6 is made of metal, it can be applied to a wide temperature range, so there is no need to use different structures depending on the temperature range as in the past, and it is only necessary to manufacture one type. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view, FIG. 2 is a partially enlarged sectional view, and FIG. 3 is a perspective view of a portion of the seal ring.
FIG. 4 is a sectional view of another example, and FIG. 5 is a partially enlarged sectional view thereof. 1... Body, 2... Ball, 3... Seat ring, 3a... Inner ring, 3b... Outer ring, 4... Threaded joint, 5... Recessed step,
6... Seal ring, 11... Covering body, 12...
Spiral spring, 13...slit.

Claims (1)

[Claims] 1. In a metal touch type ball valve in which a metal seat ring is brought into contact with a ball, an annular covering made of a highly ductile metal is covered with an endless spiral spring, and slits are formed around the entire circumference of the covering. A seal ring is provided, and the seat ring is composed of an inner ring and an outer ring screwed to the inner ring, and the seal ring is inserted into the screw joint to create a seal between the seat ring and the body. A ball valve characterized by: