JPS6035585B2 - Sealing member of ball valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a sealing member for a ball valve that shuts off and opens fluid quickly and with minimal pressure loss.

Like a cock, ball valves can be opened and closed simply by turning the valve stem 90 degrees, and are extremely quick to operate.Moreover, the flow path is formed in a straight line without deforming the cross section of the flow path. Therefore, the fluid pressure loss is much smaller than that of a normal blocking valve.

For this reason, the fields of its use are expanding more and more, as exemplified by nuclear power plants.

However, the ball seat as a sealing member used in conventional ball valves is generally made of tetrafluoroethylene resin, and is a general-purpose ball seat that can only be applied to low-load and low-temperature regions up to about 150q0. It is a sexual thing.

However, recently in industry, there has been a demand for ball sheets made of phenolic resin, ball sheets made of bran-fed graphite, or ball sheets made of bran-fed graphite, which have heat resistance and mechanical strength, under conditions of high temperature or high pressure fluids. Ball seats made of expanded graphite and the like have been proposed.

Products made of phenolic resin tend to lack flexibility in molds and dimensions during manufacturing, and due to thermal expansion of the balls that make up the valve disc at high temperatures, they tend to seize on the rotating surface with the balls. In addition, since it is a hard resin, it has poor sealing properties on the rotating surface, is susceptible to surface assemblage, and has poor sealing properties. In addition, those made of sintered graphite have excellent heat resistance, but are mechanically fragile and have the disadvantage of being susceptible to damage such as cracking and chipping under high pressure and high temperature atmospheres.

Furthermore, binderless ones made of expanded graphite have good compatibility with the ball on the rotating surface and have low torque, but are brittle and have problems with sealing properties caused by collapse, cracking, wear, etc.

Therefore, this invention solves the above-mentioned drawbacks of ball sheets all at once, and has a structure that does not crumble or crack even when exposed to high temperatures or high pressures, has wear resistance, and is resistant to corrosion by chemicals. The purpose of the present invention is to provide a new ball valve sealing member that is practically effective and has excellent sealing properties.

An embodiment of the present invention will be described below in detail based on the drawings.
In Figure 1, 1 is the pole valve body, 2 is the ball, and 3
is a sealing member. The above-mentioned sealing member 3 includes a ball seat 5 having a contact surface 4 with the ball 2 as shown in FIG.
It is formed by a reinforcing ring 6 made of metal that holds the outer peripheral surface of the ball seat 5, and a flexible sheet 7 adhered to the back surface of the contact surface 4 of the ball seat 5.

The ball sheet 5 mentioned above is mainly made of expanded graphite in order to improve the heat resistance of the sheet itself and smooth spreading with the balls 4, and it is also made of heat resistant phenolic resin to improve resistance to collapse, cracking, and abrasion. It is formed by combining 10 to 15% of /winder.

In this way, the ball sheet 5 is made by combining 10 to 15% of the heat-resistant binder made of phenolic resin with expanded graphite. As can be seen, the effect of deformation and the effect of increasing torque is the least, and it exhibits excellent effects in all aspects such as torque characteristics, sealing characteristics, and load-bearing characteristics.Here, the experiment was conducted under the following conditions. Ta. (
Experimental conditions) Test machine: An improved version of a ball valve for nuclear power (size: lees, 150 pounds).

Ball seat size: In Figure 2, A: 8.5 Yanagi mouth: 91 C: 80 side 2: 94 No. H: 98 Yanagi smooth twill area S: 14.8 Liquid: Industrial water temperature: Room temperature 25oo Fluid pressure: 0.5-20k9' (carried out in stages)
The ball sheet 5 in the above experiment was made of a heat-resistant binder made of 12% phenol resin and expanded graphite particles (in the C-axis direction of graphite particles having a particle size distribution peak of 100 mesh (149 m) in original particle diameter). direction perpendicular to the graphite layer surface)
It was expanded by about 8 folds, and the graphite particles were worm-shaped.

) was mixed in a mixer and molded. However, if the amount of phenolic resin binder in the ball seat 5 is less than 10%, it will have a strong effect on deformation, and if it exceeds 15%, the torque will tend to increase, so the appropriate value is 10 to 15%. % is the most effective.

In addition, by forming the reinforcing ring 6 from a metal such as heat-resistant alloy steel, not only the heat resistance but also the prevention of collapse, cracking, and wear of the ball seat 5 are dramatically improved.
It also has a structure that can withstand high loads.

Furthermore, since the above-mentioned flexible sheet 7 is formed from an expanded graphite sheet having flexibility, the compressibility of the ball seat 5 can be compensated for by this flexible sheet 7, and the elasticity can be imparted to the ball seat 5. It also serves to increase the sealing effect between the ball valve body 1 and the back side of the ball seat 5. The sealing member of the ball valve of the present invention constructed in this way uses expanded graphite impregnated with 10 to 15% phenol resin as a binder, and its outer peripheral surface is held by a metal reinforcing ring, and the back side is Since it is constructed by positioning a flexible sheet made of expanded graphite, it has the following effects.

■ It can be used in high-pressure, high-temperature areas where conventionally only metal ball seats were applicable, and has many benefits such as significantly improved sealing performance and more compact valves compared to metal ball seats.

■ The phenolic resin binder compounded with the expanded graphite was set at 10 to 15%, so if it is less than 10%, it will have a strong effect on deformation, and if it exceeds 15%, it will have an effect on increasing the torque. Although not preferred, it is most effective to set the appropriate value within the above range, and the present invention provides excellent torque characteristics, sealing characteristics, load-bearing ability, etc. ■ The configuration includes a reinforcing ring that holds only the outer circumferential surface of the ball seat, and a movable seat located on the back of the ball seat, so it exhibits high load capacity with high safety as a sealing part of the ball valve. (See Figure 4) and not only has excellent compression and recovery properties, but also exhibits good sealing properties without causing stress or distortion due to thermal expansion of the ball sheet, particularly in high-temperature atmospheres.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view of a ball valve, FIG. 2 is a partially cutaway enlarged sectional view of a sealing part,
FIGS. 3 and 4 are comparison graphs comparing the product of the present invention with products made of other materials. 1...Ball valve body, 2...Ball, 3...
Seal club village, 4... support side, 5... ball sheet, 6
... Reinforcement ring, 7... Flexible sheet. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 A ball valve having a fluid sealing member, wherein the sealing member is made of a ball sheet made of expanded graphite combined with a binder made of 10 to 15 wt% phenolic resin, and a metal plate that holds the outer peripheral surface of the ball sheet. A sealing member for a ball valve, characterized in that it is formed by a reinforcing ring and a flexible sheet made of expanded graphite located on the back side of the contact surface of the ball seat.