JPH08338540A - Pneumatic two-stage opening/closing valve device - Google Patents

Abstract

PURPOSE: To improve reliability of a seal by spherically forming a part of a valve body interlocked with a valve seat in the upper course of a flow passage in a valve means, rotatably arranging the valve body around a shaft which is eccentrically and perpendicularly arranged to a flow passage axis, making the valve body and the valve seat be in press contact with a closed valve seat without sliding, and thereby reducing abrasion. CONSTITUTION: In a valve means 2 of a two stage opening/closing valve device 1, a valve body 8 has a spherically formed seal part. A flexible plug arm 8a is integrated with a surface of the valve body 8 in a perpendicular manner. A semi-cylindrical hub 9 is integrated with the other end of the plug arm 8 on an eccentric position. A rotary shaft 9a for rotating the valve body 8 is arranged on an eccentric position in respect to an axial line O of the hub 9. A valve seat 7 interlocked with the valve body 8 is arranged on an inflow port 6a of a casing 6. When the valve body 8 is rotated from an opening position indicated by two-dot chain line to a closing position indicated by a solid line, the plug arm 8 is elastically deformed. Due to the elasticity, the valve body 8 is in pressure contact with the valve seat 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-actuated two-stage on-off valve device, and more particularly to an air-operated two-stage on-off valve device according to an opening / closing program.
Air-operated two-stage open / close valve device that combines a long-life open / close valve that is driven to open / close in stages and a valve drive device that uses an air cylinder that stably drives the open / close valve to batch shipments such as lory shipment and ship shipment. Used.

[0002]

2. Description of the Related Art When quantitatively filling a liquid, it is desirable to fill the liquid at a high flow rate and a high flow rate from the viewpoint of improving work efficiency. However, the liquid is flammable and low conductive petroleum,
When this petroleum is mounted on a lorry vehicle through a nozzle such as a loading arm, static electricity is generated in the oil liquid as the flow velocity of the oil liquid increases, and when the amount of static electricity increases, the static electricity is generated between the tip of the loading arm and the oil liquid surface. Since there is a risk of fire occurring due to discharge sparks during the discharge, the flow velocity is reduced during the period from the start of filling until the oil surface during filling contacts the tip of the loading arm, and the flow velocity is increased during the subsequent filling period.
The filling operation is performed by opening the valve in stages. On the other hand, if high-speed filling is continued until the filling progresses and reaches the set amount, the fluid inertia causes the valve closing to delay and overfilling occurs.As a filling error and a water hammer occur, overfilling is prevented when the filling amount nears the fixed amount is reached. The flow rate is reduced to improve the filling accuracy.

For this reason, the relationship between the filling flow rate and the flow velocity is programmed at the time of shipping of the truck, and the valve device is controlled in two stages according to this program. This two-stage control is usually a two-stage control of a small flow velocity region at the beginning of filling and just before the completion of filling, and a large flow velocity region at the middle of filling, as described above.
Such a two-stage on-off valve device (hereinafter referred to as a valve device) is
It is composed of a valve means and a drive device for driving the valve means, which are integrally formed, but are usually driven by air pressure from the viewpoint of explosion proof.

The valve device, for example, is frequently used per day when it is used for shipping trucks, and the number of times of opening and closing of the valve is enormous throughout the year. Therefore, the number of failures increases, so that failure repairs and periodic inspections are required. The time lost is enormous, which reduces the efficiency of the filling operation and increases the economic loss.
The normally used valve means is a ball valve, and as described above, a pneumatic actuator is used as the valve drive device from the viewpoint of explosion proof.

FIG. 6 is an exploded perspective view for explaining a seat portion of a ball valve, in which 20 is a ball valve main portion, 2
1, 22 are casings, 23 are balls, 24 are seats,
25 is a packing, 26 is a bolt, and 27 is a nut.

The ball 23 is a spherical body, has a through hole 23b penetrating the center thereof, and has a groove 23a engaged with a drive shaft 21a for rotating the ball 23 in a direction perpendicular to the axis of the through hole 23b. Has been. The ball 23 has a through hole 23.
b is sealed by an annular sheet 24 on the upstream and downstream sides,
The valve is opened and closed by rotating the drive shaft 21a which is liquid-tightly housed in the paired casings 21 and 22 and sealed by the bolt 26 and the nut 27 via the packing 25 and which engages with the groove 23a. There is.

A drive unit (operating unit) for driving the valve means
Is often used because it is inexpensive, reliable, and easy to operate. However, in the structure in which the valve means receives the fluid dynamic pressure according to the valve opening degree, the valve opening degree when the fluid is flowing is affected by the dynamic pressure even if the valve opening degree is normal under no load. The valve opening becomes unstable. In order to eliminate such instability of the opening degree, the positioner is used to detect the position of the valve opening degree to form a closed loop for controlling the valve opening degree to stably and correctly control the valve opening degree.

Although many types of positioners have been proposed, as a basic configuration, a signal detecting section using a bellows, etc., a pilot section which opens and closes according to its movement, and a movement of the output shaft in the pilot section It is composed of a link, a spring or the like for feeding back to the equilibrium state. The pilot part has a fixed nozzle and a flapper that is displaced according to the movement of a bellows or the like, and takes out the displacement of the flapper as a change in the nozzle back pressure.

[0009]

The valve normally used in the conventional valve device in which the valve body and the valve drive device are integrally formed is a ball valve. As shown in FIG. 6, in the ball valve, the ball 23 and the seat 24 are slidably provided, and a flexible resin such as Teflon is used as the seat 24. A ball valve with such a configuration
The ball 23 adheres closely to the seat 24 due to the differential pressure between the upstream and downstream sides,
The larger the differential pressure, the better the shut-off property. However, each time the ball valve is opened and closed, the ball 23 slides on the downstream seat 24 with a large pressure, so that the following defects occur.

(1) The larger the differential pressure is, the larger the friction is. Therefore, malfunction is likely to occur and an accident leading to an overflow is likely to occur. (2) The downstream seat 24 is repeatedly opened and closed for a long period of time to be worn, the gap between the ball 23 and the seat 24 becomes large, and when the differential pressure decreases due to the pump stopping, etc., forgetting to close the loading arm tip valve, etc. The phenomenon that the oil accumulated in the pipe drips indefinitely occurs. (3) When the pump discharge pressure is higher, a step difference is created in the seat portion due to the pressure difference when the intermediate opening of the first stage is made, and the closing speed becomes unstable when moving to the fully closed position of the second stage. This may cause frequent hammer and overfill alarms or overflow. (4) During the valve operation test, the manual valve provided on the upstream side is closed and the differential pressure is zero, so the valve operates smoothly unlike the condition of use, which delays the elucidation of the cause after an accident. (5) For the above reasons, ball valve manufacturers recommend that they be maintained once a year.

On the other hand, in a pneumatic valve driving device having a nozzle and a flapper, it is necessary to finely adjust the gap between the nozzle and the flapper, and moreover, the nozzle is clogged or blocked, so that the valve opening / closing cannot be performed. Since an accident such as an overflow occurs, regular inspection is required, maintenance cost is increased, and shipping work must be stopped during that period, resulting in inefficiency.

As described above, the valve device used for batch shipping of oil liquids such as conventional lory shipping has a system combining a ball valve and a two-stage open / close air cylinder driving device, and a cam flex valve. There has been a system in which a positioner type driving device is combined with the above. However, the former valve device
The drive device with a two-stage open / close air cylinder is durable and highly reliable, but the ball valve is not long-term reliable, and the latter valve device has a camflex valve that operates stably for a long period of time and is highly reliable. The mold driving device had a problem in reliability, and it was not possible to stably use the valve device of any of the conventional methods for a long period of time.

In order to solve the above problems, the present invention relates to a valve device including a valve device and a drive device that have been conventionally used for batch shipping and the like, and a cam flex valve as the valve device with a low failure rate and an air valve as the drive device. Combining cylinders,
It is an object of the present invention to provide a substantially maintenance-free air operated two-stage on-off valve device.

[0014]

In order to solve the above-mentioned problems, the present invention provides a two-stage on-off valve device attached to a flow tube for taking in a fixed amount of fluid flowing in the flow tube. An annular valve seat provided in parallel and a sealing surface that rotates around an eccentric shaft that is eccentric at right angles to the axis of the flow tube and that opens and closes the flow tube in cooperation with the valve seat have a spherical surface. A valve means comprising a valve body; a two-stage air cylinder having a plurality of pistons that move in two stages on the same axis, and a linear motion in which the piston moves by engaging the eccentric shaft and the moving shaft. The valve drive device includes a locking unit that converts the eccentric shaft into a rotational movement, and a drive unit that controls opening and closing of air pressure that drives the air cylinder to open and close the valve unit according to an opening and closing program. It is characterized by that.

[0015]

The valve element is rotated by an axis eccentric to the axis of the flow tube and is eccentric to the valve element, and comes into contact with the annular valve seat without sliding. The air-operated two-stage open / close valve device is capable of positioning an intermediate opening degree and is combined with a stable air cylinder type drive unit and is substantially maintenance-free.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view for explaining the structure of an air-operated two-stage on-off valve device according to the present invention, FIG.
FIG. 1 (b) is a front view seen from the flow direction.
Is an air operated two-stage on-off valve device, 2 is a valve means, 3 is an air cylinder, 4a and 4b are solenoid valves, and 5 is a pressure reducing valve (with a filter).

The air-actuated two-stage on-off valve device 1 engages an eccentric shaft 2a that rotationally drives a valve body (not shown) of the valve means 2 with an air cylinder 3 to eccentric the linear movement of the air cylinder 3. Engaging means (not shown) for converting rotational movement of the shaft 2a
And solenoid valves 4a, 4b that comply with explosion-proof regulations for driving the air cylinder 3 according to a valve opening / closing program, and a pressure reducing valve 5 having a filter for reducing the pressure to a pressure suitable for driving the air cylinder 3. The opening degree is indicated by the valve opening degree indicator 3c. Hereinafter, the valve means as a main part and the air cylinder 3 as a drive part will be described with reference to the drawings.

FIG. 2 is a sectional view for explaining the valve means applied to the present invention, as seen from the direction perpendicular to the flow. In the figure, 6 is a casing, 7 is a valve seat, 8 is a valve element, and 9 is a valve. It's a hub.

The valve means 2 shown in the figure is, for example, a cam flex valve manufactured by Niigata, Mensoneilan Co., Ltd. A plug arm 8a having a predetermined length and a semi-cylindrical hub 9 at an eccentric position on the other end side of the flexible plug arm 8a. The valve body 8, the plug arm 8 and the hub 9 are integrally formed. It is configured. The rotating shaft 9 is placed at a position eccentric to the axis O-O of the hub 9.
a is provided so that the valve body 8 can be driven to be rotatable around the rotation shaft 9a (from the position indicated by the two-dot chain line on the paper to the position indicated by the solid line).

The valve body 8 is rotatably installed in the center of the casing 6 having the inflow port 6b and the outflow port 6a on the axis OO. An annular valve seat 7 that cooperates with the valve body 8 is provided at the inlet 6b of the casing 6 in parallel with the cross section of the inlet 6b, and the valve body 8 is closed from the valve opening position indicated by the two-dot chain line by a solid line. When rotating to the valve position, since it is eccentric, the valve body 8 and the valve seat 7 do not come into contact with each other until just before they are sealed, and no friction occurs. When the valve is closed, the plug arm 8a is elastically deformed,
Due to this elasticity, the valve body 8 is stably pressed against the valve seat 7 and sealed.

As described above, the operation of the valve means 2 by the cam flex valve is such that the valve body 8 and the valve seat 7 do not slide until just before the valve is closed, and when the valve is closed, the elastic force of the plug arm 8a. Since the valve body 8 and the valve seat 7 do not friction with each other and are closed by the elastic force of the plug arm 8a after the valve is closed, the valve can be stably opened and closed without liquid leakage for a long period of time. You can

The air cylinder 3 is used as a drive device which operates in a similar and stable manner corresponding to the valve means 2 of the cam flex valve capable of stable operation for a long period of time, and the structure of the air cylinder 3 will be described below. Then, the control by the solenoid valves 4a and 4b for driving the air cylinder 3 according to the program will be described. First, the program for opening and closing the valve will be described.

FIG. 3 is a time chart for explaining an example of the valve opening / closing program, in which the horizontal axis represents the filling amount and the vertical axis represents the valve opening degree. In FIG. 3, the period from a to b to c is the first stage valve opening for filling with a small flow rate, and the period from c to d is the second stage valve opening for filling with a large flow rate, d → e
During the period up to, the second stage valve open state is maintained in the filling intermediate region, and the first stage valve is closed during the period of e → f → g near the set filling amount, and immediately before the fixed amount filling. It is completely closed in the period of g → h.

FIG. 4 is an example of a block diagram for explaining the valve opening operation. In the figure, 10 is a piston of the first stage opening / closing drive unit 3a, 11 and 12 are pistons of the second stage opening / closing drive 3b,
Reference numeral 13 is a locking member, 14 is an eccentric shaft fixing hole, 15 is a speed controller, 16 is a flow path, and 17 is a pressure gauge.

The air pressure is adjusted to a predetermined pressure while observing the pressure reducing valve 5 with the pressure gauge 17, and is supplied to the flow path 16. The two-stage valve opening operation in the periods a to d of FIG. 3 will be described below. (1) Operation of the first-stage valve (open) (period a → b → c in FIG. 3) [solenoid valve 4a: OFF solenoid valve 4b: ON] The solenoid valve 4b is turned off when the solenoid valve 4a is off. When the air is turned on, air is introduced into CY ₁ through E ₁ → OUT ₁ , and the piston 10 is pushed in the direction of arrow P ₁ (right side in the figure), and at the same time, the air in CY ₂ is exhausted through OUT ₂ → E ₂ . Since the piston rod 10a and the surface of the piston 11 are in contact with each other, the piston 11 is pushed in the direction of the arrow P ₂ (to the right in the figure) and the locking member 13 is rotated in the direction of the arrow "open" (clockwise) to move the piston. The valve is opened corresponding to 10 defined strokes. (2) Operation of the second stage valve (open) (period c → d → e in FIG. 3) [solenoid valve 4a: ON solenoid valve 4b: ON] The solenoid valve 4b continues to be turned on and the solenoid valve 4a is turned on. Causes the air to pass through E ₃ → OUT ₃ and enter CY ₃ , and the air in CY ₄ is released to the atmosphere by OUT ₄ → E ₄ , so that the piston 1
1, 12 are further pushed in the direction of arrow P ₂ and the locking member 13 is further rotated in the direction of “open” arrow to open the valve. At this time, the piston rod 10a and the piston 11 are separated.

FIG. 5 is an example of a block diagram for explaining the valve closing operation. The parts which operate in the same manner as in FIG. 4 are designated by the same reference numerals as in FIG. (3) Operation of the first stage valve (closed) (period e → f → g in FIG. 3) [solenoid valve 4a: OFF solenoid valve 4b: ON] The solenoid valve 4b continues to be turned on and the solenoid valve 4a is turned off. Causes air to enter CY ₄ through E ₃ → OUT ₄ and at the same time C
The air of Y ₃ is released to the atmosphere via OUT ₃ . Note that C
The flow rate of air flowing out from Y ₄ is adjusted by the speed controller 15 in which the check valve 15a and the variable nozzle 15b are connected in parallel so that a predetermined flow rate gradient is obtained when the valve is closed. (4) Second-stage valve (closed) operation (g → h period in FIG. 3) [solenoid valve 4a: OFF solenoid valve 4b: OFF] When the solenoid valve 4a is OFF, the solenoid valve 4b is OFF. Air enters CY ₃ from E ₁ through OUT 2 and CY
The air of ₁ is released to the atmosphere from OUT1 and moves in the direction of arrow F ₁ . At this time, since the air of CY ₄ is continuously supplied, the pistons 11 and 12 move in the arrow F ₂ direction and rotate the locking member 13 in the arrow “closed” direction.

According to the valve driving means using the air cylinder 3 described above, a sufficiently large driving force can be obtained, and since the piston 10 is mechanically provided with a stopper in the P ₁ direction, the opening of the first stage is the positioner. Unlike the above, it is stable, the position does not change, there is little maintenance, and stable long-term operation is possible.

[0028]

As is apparent from the above description, in the valve means and the drive device, which are the essential parts of the air-operated two-stage on-off valve device according to the present invention, the valve means is parallel to the cross section of the upstream flow pipe. The portion of the valve element that cooperates with the valve seat provided on the curved surface is a spherical surface, and the valve element is rotated around an axis eccentric to the flow tube axis at a right angle, and the valve element and the valve seat are closed. Since it has a structure in which it is pressed against the valve seat without sliding, there is no friction or wear even if it is repeatedly opened and closed for a long period of time, and the probability of an accident such as liquid leakage is low. Further, since the driving device is composed of the air cylinder and the solenoid valve that drives the air cylinder in multiple stages according to the opening / closing program, it operates mechanically and can be used stably for a long period of time. Therefore, the pneumatically operated two-stage on-off valve device constituted by the valve means and the drive device can be used maintenance-free with almost no need for uneconomical and cumbersome maintenance and inspection, which is highly economical.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the structure of an air operated two-stage on-off valve device according to the present invention.

FIG. 2 is a cross-sectional view seen from a direction perpendicular to a flow for explaining valve means applied to the present invention.

FIG. 3 is a diagram for explaining an example of a valve opening / closing time chart, in which the horizontal axis represents the filling amount and the vertical axis represents the valve opening.

FIG. 4 is an example of a block diagram for explaining a valve opening operation.

FIG. 5 is an example of a block diagram for explaining a valve closing operation.

FIG. 6 is an exploded perspective view for explaining a seat portion of the ball valve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air-operated two-stage on-off valve device, 2 ... Valve means, 3 ... Air cylinder, 4a, 4b ... Electromagnetic valve, 5 ... Pressure reducing valve (with filter), 6 ... Casing, 7 ... Valve seat, 8 ... Valve body, 9 ...
Hub, piston of the first stage opening / closing drive unit 3a, 11,
12 ... Piston of second stage opening / closing drive 3b, 13 ... Locking member, 14 ... Eccentric shaft fixing hole, 15 ... Speed controller, 16 ... Flow path, 17 ... Pressure gauge.

Claims (1)

[Claims] 1. A two-stage on-off valve device attached to a flow tube for taking in a fixed amount of fluid flowing in the flow tube, comprising: an annular valve seat provided parallel to a cross section of the upstream flow tube; Valve means comprising a valve body having a spherical sealing surface for pivoting around an eccentric axis that is eccentric to the axis of the valve and opening and closing the flow tube in cooperation with the valve seat; A two-stage air cylinder having a plurality of moving pistons, a locking means for engaging the eccentric shaft and the moving shaft, and converting a linear motion of the piston movement into a rotary motion of the eccentric shaft, and the valve. An air-actuated two-stage on-off valve device comprising a valve drive device including a drive unit that controls opening and closing of air pressure for driving the air cylinder to open and close the means in accordance with an opening and closing program.