JP2607305B2 - Plug valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug valve, particularly a lift-type plug valve used at high pressure and a filter device for a synthetic resin using the valve.

[Conventional technology]

The plug valve has a structure in which the plug is pressed against the valve body to prevent fluid leakage.The area for sealing is larger than other types of valves, so the plug is pressed against the valve body with a very large force. Have been.

Especially in the case of high pressure plug valves, it is not uncommon to be pressed with a force of several tens of tons, and in most metal plug valves, turning the plug while applying such a large force will peel off the surface, The so-called galling phenomenon easily occurs.

In order to prevent such galling, a method of coating various materials on the sliding surfaces of the plug and the valve body has been attempted, but it is not perfect for preventing galling, and therefore, only when sealing. There has been proposed a plug valve of a type in which surface pressure is applied and the plug is once lifted and rotated backward when rotating. It can be said that this type of plug valve achieves both anti-galling and sealing purposes.

In addition, when a plug valve is used for a high-viscosity fluid such as a polymer, the purpose of sealing is achieved even when the surface pressure pressing the plug against the valve body is smaller than that of a low-viscosity fluid such as water due to its high viscosity. In some cases, a type in which rotation is performed without a lift, limited to the use of a highly viscous fluid such as a polymer, has been put to practical use.

FIG. 2 shows the relationship between the plug of the plug valve and the taper of the valve body.

In FIG. 2, the taper of the plug 1 of the plug valve is
JIS specifies 1/6, that is, this taper is about 5
゜ Angles before and after are commonly used.

When pushing plug 1 into valve body 2, plug 1
Between the axial force P and the total pressure Q of the conical contact surface of the plug 1, the inclination angle β of the plug 1, and the coefficient of friction μ between the plug 1 and the valve body 2, P = Q (sin β + μcos β). 1) that the smaller the inclination angle β of the plug 1 is,
With the axial force P of the small plug 1, the larger plug 1
The total pressure Q of the conical contact surface is generated. JI
S adopts taper 1/6 based on this concept.

 When the plug 1 is extracted, the above relationship changes to P = Q (sin β−μcos β) (2).

Therefore, when β = 3 ° to 5 ° where μ = 0.05 to 0.1, P in the expression (2) becomes a negative number, and it can be seen that force is required to pull out the plug 1. In other words, at an angle defined by JIS, a so-called wedge effect requires more force than necessary to pull out the plug 1 and rotate the plug.

In a high-pressure plug valve, the above P and Q become very large forces, so that if it does not rotate after being lifted, a galling phenomenon will occur. It can be clearly understood from the equation (1) that when β is lifted, the smaller β is, the smaller the force P in the axial direction of the plug 1 is compared to the larger surface pressure, and the smaller the force required for lift is.

On the other hand, for plug valves that do not lift,
If the plug 1 is not set at an angle at which the wedge effect does not work, a large force is required for the rotation, which may cause galling. Therefore, in this case, the inclination angle is generally about 10 °. In addition, this method can seal a high-viscosity fluid only when the pressure is not extremely high.

[Problems to be solved by the invention]

As described above, the plug valve of the type in which the plug is lifted and then rotated is always required to perform two operations of "lifting" and "rotating", so that there is a problem that the operation is complicated.

For plug valves that do not lift,
It still leaves Kaziri's anxiety.

Therefore, in order to solve the above-mentioned problems, the present invention has conducted various experiments, and as a result, using a plug having a tilt angle as small as possible that can eliminate the wedge effect, leaving a lift mechanism, and in principle not lifting It is an object of the present invention to provide a plug valve which can be easily operated for rotation and can prevent occurrence of galling based on this.

[Means for solving the problem]

In order to solve the above-described problems, a first aspect of the present invention provides a plug valve in which a plug can be selected between a case where the plug is rotated without being lifted and a case where the plug is once rotated after being lifted. In this case, the inclination angles of the conical inner peripheral surface of the tapered hole provided in the valve body and the conical outer peripheral surface of the plug fitted to the taper hole with respect to the vertical axis are set to 6 ° to 10 °, respectively. In this configuration, the dynamic mechanism is provided with a torque regulating mechanism for interrupting the transmission of rotation when the rotational torque of the plug becomes larger than the force causing galling.

The second invention provides a plug valve of a type in which a plug can be selected between a case in which the plug is rotated without being lifted and a case in which the plug is once lifted and then rotated. Using two plug valves whose inclination angles with respect to the vertical axis of the conical inner peripheral surface and the conical outer peripheral surface of the plug fitted to this are set to 6 ° to 10 ° respectively, the plugs of both valves are synchronized by a rotating mechanism. The rotation mechanism is interlocked with the rotation mechanism, and the rotation mechanism is provided with a torque regulating mechanism that interrupts the transmission of rotation when the rotation torque of the plug becomes larger than the force that causes galling.

The third invention employs a configuration in which the plug valve is a three-way plug valve and is connected to the filter housing of the switching port of the valve.

[Action]

The rotation of the plug is performed without lifting. If, for some reason, the turning torque becomes larger than the force causing the galling, the turning operation is prevented by the operation of the torque regulating mechanism of the turning mechanism. In such a case, the rotation operation is temporarily stopped, the plug is lifted, and then the rotation operation is performed again.
Then, since the major cause of the rotation torque is removed by the lift of the plug, the rotation can be smoothly performed this time.

Of course, if the torque regulating mechanism of the movable mechanism does not work, the turning operation may be performed as it is.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the plug valve 11 has a plug 14 rotatably incorporated in a tapered hole 13 of a valve body 12 and a plug 14.
A lower shaft 15 is coupled to the lower end of the valve shaft, and a disc spring 18 is contracted between the adjustment nut 16 and a thrust bearing 17 located at a lower portion of the valve book 12 by being screwed to the lower shaft 15, and a disc spring 18 The plug 14 is constantly pulled downward to be in pressure contact with the tapered hole 13 to prevent fluid leakage, and the adjusting nut 16 adjusts the pulling force of the plug 14.

The turning mechanism 19 of the plug 14 is mounted on the upper shaft 20 connected to the upper end of the plug 14 in an externally fitted state with the worm wheel 21 connected by a key 22, and the worm 23 meshed with the worm wheel 21.
The handle 24 is fixed to the shaft 23a of the
The plug 14 is turned by the turning operation of.

The lift mechanism 25 of the plug 14 is formed by a nut 26 screwed to the upper end of the upper shaft 20, and the plug 14 is pulled up or down by loosening the nut 26.

The conical inner peripheral surface of the tapered hole 13 provided in the valve body 12 and the conical outer peripheral surface of the plug 14 fitted in the tapered hole 13 each have an inclination angle larger than 6 ° with respect to the vertical axis.
さ れ Set at a smaller angle, which allows plug 14
The condition is set so that the plug 14 can be rotated even when the plug 14 is not lifted.

In addition, the rotation mechanism 19 is provided with a torque regulating mechanism 27. When the rotation of the plug 14 by the handle 24 causes the rotation torque of the plug 14 to become larger than the force causing galling, the rotation transmission is interrupted. It is supposed to.

As the torque regulating mechanism 27, various types of torque limiters are used.

FIG. 1 shows that the plug valve has the above configuration, the plug 14 is set at a slightly larger inclination angle than the JIS specification, and the rotation of the plug 14 for opening and closing the flow path is performed without lifting. The operation is performed by operating the handle 24.

When the turning torque of the plug 14 becomes larger than the force causing the galling for some reason, the torque regulating mechanism 27 provided with the turning mechanism 19 works, and the middle of the turning transmission path is cut off. The turning operation of the plug 14 is prevented.

In such a case, temporarily stop the rotation operation and
To lift the plug 14 and lift it from the tapered hole 13 to perform the turning operation again.The cause of the increase in the turning torque due to the lift of the plug 14 has been eliminated. Can be rotated.

If the torque regulating mechanism 27 does not work when the plug 14 is turned, the turning operation may be performed without lifting.

By the way, a plug valve with a diameter of 50 mm was manufactured and 350
Even when used at 350 ° C. and 350 kg / cm ² , no galling occurred on the plug.

Next, FIGS. 3 and 4 show an example in which the plug valve is a three-way plug valve 11a and a filter device 31 made of a synthetic resin using two valves 11a.

The filter device 31 includes two three-way plug valves 11
a, 11a, and a pair of filter housings 32, 32.

As shown in FIG. 4, the three-way plug valves 11a, 11a
The valve body 12 is provided with a synthetic resin inflow / outflow port 33 and two switching ports 34, 35, and a switching passage 36 is formed in the plug 14,
The rotation of the plug 14 switches the communication between the switching ports 34 and 35 with respect to the inflow / outflow port 33.

The structure of the other parts of the three-way plug valves 11a, 11a is the same as that of the plug valve 11 shown in FIG.

The filter housings 32 and 32 are formed by incorporating a filter 38 inside a resin passage 37 penetrating therethrough, and removing impurities in the resin by the filter 38, and providing an air vent at the highest portion of the resin passage 37. It has a structure.

As shown in FIG. 3, a pair of filter housings 32, 32
Is a three-way plug valve with its resin passage 37 located at both ends
When the filter 38 is connected to communicate with the switching ports 34, 35 of 11a, 11a and the resin 38 passes through one of the filter housings 32, and the filter 38 becomes clogged, the three-way plug valves 11a, 11a are switched, and the other This will change the flow of resin to 32.

The plugs of the three-way plug valves 11a and 11a at both ends are connected to each other by a rotation mechanism 19, and are rotated by one handle 24.

The rotation mechanism 19 is configured such that a worm 23 meshing with the worm wheel 21 of the plug 14 is interlocked by a single shaft 23a, and a torque regulating mechanism 2 is provided between a handle 24 attached to an end of the shaft 23a and the shaft 23a.
7, the three-way plug valves 11a, 11a are simultaneously switched by the operation of the handle 24, and when the torque increases when the plug 14 rotates, the torque regulating mechanism 27 is activated, and the handle 24 Is not transmitted to the plug 14.

In such a case, the plug 14 may be lifted up by operating the lift mechanism 25, and the turning operation may be performed again.

〔effect〕

As described above, according to the present invention, the inclination angle of the conical inner peripheral surface of the tapered hole provided in the valve body and the conical outer peripheral surface of the plug fitted therein to the vertical axis is set to 6 ° to 10 °. Therefore, in principle, the plug can be rotated without lifting operation, and the torque regulating mechanism can reliably prevent the occurrence of galling of the plug. Obtainable.

In addition, the two plug valves are linked by a rotating mechanism, and a torque regulating mechanism is provided in the rotating mechanism, so that the two plug valves can be switched in synchronization with each other, and the plugs of both valves can be prevented from galling. Can be.

Further, since the filter is constructed by connecting the filter housing to the switching port of the three-way plug valve, it is possible to realize a filter device using the plug valve.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a plug valve according to the present invention, and FIG.
The figure is an explanatory diagram showing the relationship between the plug and the taper of the valve body,
FIG. 3 is a partially cutaway front view of a filter device constituted by using two plug valves, and FIG. 4 is a transverse sectional view of the same. 11 Plug valve, 12 Valve body, 13 Tapered hole, 14 Plug, 19 Rotating mechanism, 25 Lift mechanism, 27 Torque regulating mechanism.

Claims (3)

(57) [Claims] 1. A plug valve having a tapered hole provided in a valve main body, wherein the plug can be rotated without lifting the plug or when the plug is once lifted and then rotated. The angle of inclination of the inner peripheral surface of the plug and the outer peripheral surface of the conical cone of the plug to be fitted to the vertical axis are set to 6 ° to 10 °, respectively. A plug valve provided with a torque regulating mechanism that shuts off transmission of rotation when the force exceeds a force to be generated. 2. A plug valve having a tapered hole formed in a valve body, wherein the plug can be rotated without lifting the plug or when the plug is once lifted and then rotated. Using two plug valves with the angle of inclination of the inner peripheral surface and the conical outer peripheral surface of the plug fitted to the vertical axis to 6 ° to 10 ° respectively, the plugs of both valves are tuned by a rotating mechanism. A plug valve, wherein the rotation mechanism is provided with a torque regulating mechanism that cuts off the transmission of rotation when the rotation torque of the plug becomes larger than the force that causes galling. 3. The filter device according to claim 1, wherein the plug valve is a three-way plug valve, and is connected to a filter housing of a switching port of the valve.