JPH094751A - Bottom valve for tank lorry - Google Patents

Abstract

PURPOSE: To improve sealing ability and to prevent the damage and the defect of a packing and a wear ring by a method wherein the inner surface of an upper valve casing with and over which, the outer cylinder part of a valve element is brought into pressure contact and slid is coated with rigid resin having a low friction factor. CONSTITUTION: The second inner surface of an upper valve casing 2 with and over which the outer cylinder part 18 of a valve element 3 is brought into pressure contact and slid through a packing 26 and a wear ring 27 is coated with resin being rigid and low in a friction factor. Teflon is representatively used as resin and the inner surface of the upper part of an upper valve casing 2 in the shape of a cylinder is covered in a film-form manner with a formed coating part C and forms the pressure contact and slide surface of the outer surface of the outer cylinder part 18. As a result, sealing ability between the outer cylinder part 18 of a valve element 3 and the upper valve casing 2 is improved and the damage and the defect of a packing 26 and a wear ring 27 on the outer cylinder part 18 side of the valve element 3 brought into pressure contact are prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tank lorry bottom valve. That is, loading gasoline, light oil, kerosene, etc.,
The present invention relates to a bottom valve of a tank, which is used for unloading and loading in a tank truck for transporting and unloading.

[0002]

2. Description of the Related Art As a bottom valve for such a tank of a tank truck, a mechanical opening / closing type valve which has been directly opened / closed by a manual handle on the tank via a connecting mechanism has been used. Air-opening and closing type that is opened and closed using air pressure is being adopted. FIG.
FIG. 4 is a front sectional view of a conventional example of such an air opening / closing bottom valve, and this bottom valve A is composed of the following lower valve box 1, upper valve box 2,
It consisted of a valve body 3, a spring 4, an air pipe 5, a piston 6 and the like.

That is, in this type of bottom valve A, the lower valve box 1 is connected to the pipe 7 and has a valve hole 8 formed on the upper surface thereof, and a valve seat 9 is provided on the periphery of the valve hole 8 to form a tank. 1
It is attached and fixed to the opening 11 at the bottom. The upper valve casing 2 is vertically fixed in the tank 10 from the outside of the valve seat 9 of the lower valve casing 1, has a cylindrical shape with a top surface closed by a cap 25, and has an inflow port 12 formed in the lower portion. There is. The valve body 3 is
A cylindrical cylinder portion 14 that is vertically movable in the upper valve box 2 and has a closed top surface 13, and a lower end portion 15 that is formed in an outer flange shape at the lower end of the cylinder portion 14 and that can be pressed against the valve seat 9. ,
The packing 1 is provided on the inner surface of the upper valve box 2 and is erected from the lower end portion 15.
The outer cylinder portion 18 is press-contacted via 6 and the wear ring 17, and is slidable up and down. The spring 4 is interposed between the cap 25 that closes the top surface of the upper valve box 2 and the lower end portion 15 of the valve body 3, and biases the valve body 3 downward. The air pipe 5 is fixed upright from the lower valve box 1 and inserted into the cylinder portion 14 of the valve body 3. The piston 6 is fixed to the upper portion of the air pipe 5 and is in sliding contact with the inner surface of the cylinder portion 14 of the valve body 3, and an air chamber 19 communicating with the air pipe 5 is formed between the piston 6 and the top surface thereof.

Therefore, in this air opening / closing bottom valve A, as shown by the solid line in the figure, the valve element 3 is pressed downward by the urging force of the spring 4, and the lower end portion 15 of the valve element 3 is constantly pressed. Is pressed against the valve seat 9 of the lower valve box 1, the valve hole 8 is closed, and the bottom valve A is closed. On the other hand, when air is pressed into the air chamber 19 on the piston 6 from an external high-pressure air source via the air pipe 5, the air pressure in the air chamber 19 rises and the spring 4 is attached to the lower side. The valve body 3 is pushed upward against the force, and the lower end portion 15 of the valve body 3 and the valve seat 9 are separated from each other. Therefore, as shown by the imaginary line in the figure, the valve hole 8 is opened and the bottom valve A is opened, and the tank 10 of the tank 10 and the pipe 7 are connected via the inflow port 12 as shown by the arrow in the figure. Unloading from the chamber 20 is performed, and conversely, loading into the tank chamber 20 is performed.

[0005]

By the way, the following problems have been pointed out in such a conventional example. That is, in the conventional air-opening / closing bottom valve A, although the outer cylinder portion 18 of the valve body 3 has the packing 16 and the wear ring 17 as described above, the upper valve made of a light alloy such as aluminum is used. It is slidable up and down while being pressed against the inner surface of the box 2, and is slid up and down along the inner surface of the upper valve box 2 each time the bottom valve A is opened or closed, that is, the valve body 3 is raised or lowered as a whole. . As a packing 16 for sealing, which is attached to the outer cylinder portion 18 side of the valve body 3 and is slid while being pressed against the inner surface of the upper valve housing 2, a Teflon (tetrafluoride of DuPont, USA) is used. Those made of ethylene resin, which is a registered trademark, the same shall apply hereinafter) and those made of rubber were used.

Then, firstly, in the conventional bottom valve A of this kind in which the packing 16 made of Teflon is used, the characteristic of Teflon is that it is hard and has a small friction coefficient, but is poor in elasticity. It has been pointed out that due to the above, the sealability between the outer cylinder portion 18 of the valve body 3 and the upper valve housing 2 is likely to be impaired. It has been pointed out that if the sealing property is impaired, gasoline, light oil, kerosene, etc., which are loaded in the tank chamber 20 of the tank 10 and have low lubricity, leak out.

Secondly, in this conventional bottom valve A in which the other packing 16 is made of rubber, the seal is caused by the characteristic of rubber that it has a large elasticity but a large friction coefficient. However, it has been pointed out that the packing 16 is likely to be damaged or chipped due to its large frictional resistance. As described above, it has been pointed out that the rubber packing 16 is easily damaged or chipped and has a short life.

Thirdly, in this conventional bottom valve A,
With respect to the upper valve housing 2 on which the packing 16 on the outer cylinder portion 18 side of the valve body 3 is pressed and slid, careful finishing of the inner surface of the upper valve housing 2 and precise dimension matching with other components are required. Therefore, the problem of high cost was pointed out. Fourthly, in this conventional bottom valve A, the friction resistance between the packing 16 on the outer cylinder portion 18 side of the valve body 3 and the upper valve casing 2 was large. In this way, since the frictional resistance between the both pressed and slid is large, the bottom valve A is opened and closed by moving the valve body 3 up and down, so that extremely high pressure air is required, and the air consumption increases, It was pointed out that the cost would be high in this respect as well.

Fifth, in particular, in this conventional bottom valve A, the upper valve box 2 is mechanically finished, so that the finish of the inner surface is difficult to be geometrically smoothed, and it is enlarged. As a result, the concavo-convex shape on the inner surface was sharply formed and large. Therefore, the frictional resistance between the inner surface of the upper valve box 2 mechanically finished in this way and the packing 16 on the outer cylinder portion 18 side of the valve body 3 increases, and from this aspect, the above-mentioned second and It was pointed out that the problem of No. 4 would be prominent.

In view of the above situation, the present invention has been made to solve the problems of the above-mentioned conventional example, in which the outer cylinder portion of the valve body is pressed and slid via packing and wear ring. By coating the inner surface of the upper valve box with a resin such as Teflon that is hard and has a small friction coefficient, firstly, the sealing property between the outer cylinder of the valve body and the upper valve box is excellent, and secondly, packing or Damage and loss of the wear ring is prevented, and the third
In addition, finishing and dimensioning of the upper valve box is easy and easy.
Fourth, it can be opened and closed with relatively low air pressure, and fifth
In addition, because the inner surface of the upper valve box is finished geometrically smoothly,
It is an object of the present invention to propose a bottom valve for a tank truck in which the above-mentioned second and fourth points are more prominent.

[0011]

The technical means of the present invention for achieving this object is as follows. That is, the bottom valve of the tank of this tank truck is an air opening / closing type equipped with the following lower valve case, upper valve case, valve body, spring, air pipe, piston and the like. First, the lower valve box is laterally connected to a pipe, has a valve hole formed in the upper surface, a valve seat is provided at the periphery of the valve hole, and is attached and fixed to the opening at the bottom of the tank. . Also, the upper valve box is
The lower valve box is vertically fixed in the tank from the outside of the valve seat, has a vertical cylindrical shape with a closed top surface and an open bottom surface, and has an inflow port formed in the lower part of the side surface. The valve body is
A cylindrical cylinder part that is vertically movable in the upper valve box and has a closed top surface and an open bottom surface, and an outer flange formed on the lower end of the cylinder part in the valve seat of the lower valve box. A lower end portion that can be press-contacted, and an outer cylinder portion that is erected from the lower end portion and that has an upper portion press-contacted to the inner surface of the upper valve box via a packing or a wear ring, and that can slide up and down. It becomes.

The spring is interposed between the closed top surface of the upper valve body and the lower end of the valve body, and biases the valve body toward the valve seat of the lower valve body. The air pipe is vertically fixed from the lower valve box, the lower part is connected to an external high-pressure air source through an air pipe, and the upper part is connected to a cylinder of the valve body through a valve hole of the lower valve box. Coaxially inserted in the section. The piston is fixed to the upper portion of the air pipe, is in sliding contact with the inner surface of the cylinder portion of the valve body, and is in communication with the upper portion of the air pipe between the closed top surface of the cylinder portion and the like. Form a chamber. Then, the inner surface of the upper valve casing, which is brought into pressure contact with and slides on the outer cylinder portion of the valve body through the packing and the wear ring, is coated with a resin that is hard and has a small friction coefficient.

[0013]

The present invention comprises the above-mentioned means, and operates as follows. First, the bottom valve of the tank of this tank truck is normally closed. That is, the valve body is pushed down by the spring, the lower end of the valve body is brought into pressure contact with the valve seat of the lower valve box, the valve hole is closed by the valve body, and the bottom valve is closed. Next, at the time of unloading and loading using a pump, the bottom valve is opened. That is, air is press-fitted into the air chamber via an air pipe or the like to push up the valve body against the spring, and the valve body rises while the cylinder portion slides against the piston, and the lower end portion of the valve body and the lower valve box By releasing the pressure contact between the valve seats and separating them, the valve hole is released and the bottom valve is opened. Further, when unloading and loading are completed, the bottom valve is closed. That is, by releasing the air that has been press-fitted into the air chamber to the outside through an air pipe or the like, the biasing force of the spring prevails and pushes down the valve element, and the lower end of the valve element is the lower valve box. When pressed against the valve seat, the valve hole is closed by the valve body, and the bottom valve is closed.

In this bottom valve, the outer cylinder portion of the valve element is pressed against the inner surface of the upper valve box through the packing and the wear ring so that it can slide up and down. The inner surface of the valve box is coated with a resin such as Teflon that is hard and has a small friction coefficient. Therefore, the outer cylinder portion, packing, wear ring, etc. of the valve body are slid up and down while being pressed against the inner surface of the upper valve body coated in this way when the bottom valve is opened / closed by moving the valve body up and down as described above. Move.

Therefore, in the bottom valve of this tank truck, firstly, a hard resin having a small friction coefficient, such as Teflon, is inevitably used for coating on the upper valve box side. Since Teflon or the like is not necessarily used for the packing on the tubular portion side, a situation in which the sealing property is not deteriorated due to the lack of elasticity of Teflon or the like does not occur. Second,
By being pressed against the inner surface of the upper valve housing coated with a resin that is hard and has a low coefficient of friction, the packing and wear ring on the outer cylinder side of the valve body have low frictional resistance and slide smoothly. , Its damage or loss is prevented. Thirdly, since the inner surface of the upper valve casing is coated in this way, the inner surface finishing and dimensional matching of the upper valve casing can be facilitated easily.

Fourthly, by coating the inner surface of the upper valve box in this way, the packing and the wear ring on the outer cylinder side of the valve body have small frictional resistance and can be slid smoothly, so that the bottom valve The air that is pressed into the air chamber for opening and closing may be of low pressure, and the air consumption will be small. Fifthly, since the inner surface of the upper valve box is finished in shape smoothly by coating such as baking, the frictional resistance is reduced also from this surface, and the above-mentioned second and fourth points become more remarkable. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. 1, 2 and 3 show an embodiment of the present invention, FIG. 1 is a front sectional view of an upper valve box and the like in a closed state, FIG. 2 is a front sectional view of a lower valve box and the like in a closed state,
FIG. 3 is a front sectional view of the upper valve box in the open state. FIG. 5 is a side view of the tank truck.

First, as shown in FIG. 5, in the tank 10 of the tank truck, a plurality of tank chambers 2 of about 3 to 7 chambers (6 chambers in the illustrated example) are provided by partition plates P along the width direction.
It is divided into 0. And gasoline, light oil, kerosene,
Other oils or the like are loaded from a storage tank or the like on the side of the loading facility via the inlet at the top of each tank chamber 20 or a bottom valve B at the bottom of each tank chamber 20 using a pump,
Oils of different types are often loaded in each tank chamber 20. Then, the tank truck loads and transports these, and unloads them to the underground tank or the like on the unloading facility side such as the gas station at the destination via the bottom valve B and the pipe 7. Note that the pipes 7 (see FIG. 2 and the like) are also called discharge pipes, and one end side is branched and connected to each tank chamber 20 via each bottom valve B and is gathered, and the other end side is the tank 10.
It is located at the bottom of both sides of the outlet and is equipped with outlets, outlet valves, etc.

The bottom valve B is provided at the bottom of each tank chamber 20 in the tank 10 of such a tank truck. The bottom valve B is shown in FIGS.
Etc., the lower valve box 1, the upper valve box 2, the valve body 3,
Equipped with spring 4, air pipe 5, piston 6, etc.,
Overall, it is made of light alloy such as aluminum, other metal, and air-openable type. Hereinafter, these will be described in detail.

First, the lower valve casing 1 of the bottom valve B will be described. As shown in FIG. 2 and the like, the lower valve box 1 is connected to the pipe 7 laterally, a valve hole 8 is formed on the upper surface, and a valve seat 9 is provided on the peripheral edge of the valve hole 8 to form a tank. 10 is attached and fixed to the opening 11 at the bottom of the tank chamber 20. That is, the lower valve box 1 has a valve hole 8 formed on the upper surface thereof, and a valve seat 9 having a larger diameter and an inner flange shape is provided on the periphery thereof. Further, a curved tubular portion and a lateral short tubular portion are integrally provided under the upper surface, and the flow path 2 is provided inside them.
1 is formed, and piping 7 for unloading and loading is connected to the end of the short tube portion. In the lower valve box 1 as described above, the outer peripheral surface of the upper surface is aligned with the valve hole 8 and the valve seat 9 coaxially with the flange-shaped opening 11 provided at the center of the bottom of the tank chamber 20, and the gasket is formed. It is attached and fixed from below with bolts 23 and the like through 22 and the like.

Next, the upper valve box 2 of the bottom valve B will be described. As shown in FIGS. 1 and 3, the upper valve casing 2 is vertically fixed in the tank chamber 20 of the tank 10 from the outside of the valve seat 9 of the lower valve casing 1, the top surface is closed and the lower surface is opened. It has a vertical cylindrical shape and has an inflow port 12 formed in the lower portion of the side surface.
That is, the upper valve box 2 is provided on the upper surface of the lower valve box 1 described above.
However, the valve seat 9 and the outer peripheral portion are integrally provided upright, and the lower valve casing 1 and the upper valve casing 2 form a valve casing having a substantially L-shaped cross section. The upper valve box 2 has a vertical cylindrical shape and is erected on the bottom of the tank chamber 20. The top of the valve box 2 is closed by a cap 25 screwed with a screw 24, and the bottom of the side surface is closed. A plurality of inflow ports 12 are formed, and the outside of the inflow port 12, that is, the tank chamber 20 side is covered with a metal net (not shown) to prevent dust and the like from entering from the inside of the tank chamber 20. The cap 25, which is a cover, functions as a receiver for the upper end of the spring 4 and also as a stopper that regulates the rising limit of the valve body 3.

Next, the valve element 3 of the bottom valve B will be described. As shown in FIGS. 1 and 3, the valve body 3 is arranged in the upper valve box 2 so as to be vertically movable, and has a cylindrical cylinder portion 14 having a top surface 13 closed and a bottom surface opened, and a cylinder. An outer flange is formed at the lower end of the portion 14, and a lower end portion 15 that can be pressed against the valve seat 9 of the lower valve housing 1 is erected from the lower end portion 15, and an upper part is provided with a packing 26 or an inner surface of the upper valve housing 2. Wear ring 27
And an outer cylinder part 18 that is press-contacted via the outer cylinder part and is vertically slidable.

That is, the cylinder portion 14 of the valve body 3 has a cylindrical shape coaxial with the above-mentioned cylindrical upper valve box 2 and having a small diameter, and the top surface 13 is closed and the lower surface is opened, and the upper valve box 2 is formed. The height dimension is set shorter so that the upper valve box 2 can be moved up and down. Lower end 15 of the valve body 3
Is integrally connected to the lower end of the cylinder portion 14 in the form of an outer flange, and the lower surface of the cylinder portion 14 is pressed against the valve seat 9 of the lower valve box 1 from above via a packing 28 provided around the lower surface. It is separable, and the valve hole 8 is opened and closed.
Further, a plurality of through holes 29 are vertically formed in the lower end portion 15. Through such through holes 29, an oil chamber 30 formed between the upper valve box 2 and the valve body 3 and a lower portion are formed. The flow path 21 in the valve box 1 is in communication. The outer cylinder portion 18 of the valve body 3 is
It is integrally connected to the outer periphery of the lower end portion 15 described above, is coaxial with the upper valve box 2 and the cylinder portion 14, and is set to have a slightly smaller diameter than the upper valve box 2 and a larger diameter than the cylinder portion 14. . On the upper part of the outer cylinder part 18, that is, on the outer peripheral side of the upper part of the outer cylinder part 18 that is pressed against and slid on the inner surface of the upper valve housing 2, ring-shaped packings 26 and wear rings 27 are arranged from top to bottom. , Packing 26 is attached by utilizing the respective circumferential grooves.

Next, the spring 4 of the bottom valve B will be described. As shown in FIGS. 1 and 3, the spring 4 is interposed between the cap 25 that closes the top surface of the upper valve box 2 and the lower end portion 15 of the valve body 3 to connect the valve body 3 to the lower valve. Valve seat 9 in box 1
Is urged toward. That is, the spring 4 is a compression spring that urges the valve body 3 as a whole while utilizing the lower surface of the cap 25 and the upper surface of the lower end portion 15 of the valve body 3 as upper and lower seats, respectively.

Next, the air pipe 5 of the bottom valve B will be described. As shown in FIG. 1, FIG. 2, FIG. 3, etc., the air pipe 5 is vertically fixed from the lower valve box 1, and the lower part is connected to an external high pressure air source via an air pipe (not shown). ), The upper portion is coaxially inserted into the cylinder portion 14 of the valve body 3 through the valve hole 8 of the lower valve housing 1. That is, the lower portion of the air pipe 5 in the illustrated example is fixed to a mounting hole 31 that is a through hole vertically provided in the bottom portion of the lower valve box 1, and thus vertically fixed as a whole. An air inlet / outlet 32, which is a through hole, is laterally formed in the mounting hole 31, and an air inlet / outlet port 32 is provided at a lower portion of the air pipe 5 via the mounting hole 31.
Therefore, it can be switched and connected to an air source or an opening (not shown) through the air inlet / outlet 32 and an external air pipe. In FIG. 2, D is color and 3
3 is a nut, and 34 is a cap that closes the lower end of the mounting hole 31.

Next, the piston 6 of the bottom valve B will be described. As shown in FIGS. 1 and 3, the piston 6 is fixed to the upper portion of the air pipe 5 and is in sliding contact with the inner surface of the cylinder portion 14 of the valve body 3 and the closed top surface 13 of the cylinder portion 14. An air chamber 19 communicating with the upper portion of the air pipe 5 is formed between the air chamber 19 and the like. That is, the piston 6 of the illustrated example has a vertical hole H that is a vertical through hole formed in the center,
The lower part is attached and fixed to the upper end part of the air pipe 5 so that the vertical holes H communicate with each other coaxially, and the outer surface of the valve body 3 is fixed.
The packing 35 and the wear ring 3 are provided on the inner surface of the cylinder portion 14 of the
It is slidably contacted via 6. The piston 6 communicates with the upper end of the air pipe 5 via the vertical hole H and forms a closed air chamber 19 between the upper surface of the piston 6 and the top surface 13 of the cylinder portion 14 or the upper portion of the inner surface thereof. .

The bottom valve B is of an air opening / closing type having such a lower valve case 1, an upper valve case 2, a valve body 3, a spring 4, an air pipe 5 and a piston 6. As shown in FIGS. 1 and 3, in the bottom valve B, the outer cylinder portion 18 of the valve body 3 is further pressed and slid through the packing 26 and the wear ring 27, so that The inner surface is coated with a resin that is hard and has a low coefficient of friction by baking or the like. Then, the upper portion of the outer tubular portion 18 of the valve body 3 is pressed against and slid on the inner surface of the upper valve housing 2 on which the coating portion C is thus formed. Teflon is typically used for the coating, but it is also possible to use various other resins that are hard and have a low friction coefficient. The formed coating portion C covers the inner surface of the upper portion of the cylindrical upper valve box 2 in a film-like manner, and serves as a pressure contact and sliding surface for the outer surface of the outer tubular portion 18 of the valve body 3. Then, such pressure contact and sliding are carried out entirely or partially through the packing 26 and the wear ring 27 attached to the outer cylinder portion 18 of the valve body 3.

The present invention is configured as described above. Then it becomes as follows. The tank truck is installed in each tank chamber 20 in the tank 10 with gasoline, light oil, kerosene,
Other oils, etc. are loaded, transported and unloaded. First, the bottom valve B attached and fixed to the opening 11 at the bottom of each tank chamber 20 of the tank 10 is normally closed as follows. That is, as shown in FIGS. 1 and 2, the valve body 3 is pressed downward by the urging force of the interposed spring 4, and the lower end portion 15 formed in the outer flange shape of the valve body 3 is removed. , And is pressed against the valve seat 9 of the lower valve housing 1 via the packing 28. As described above, the valve hole 8 of the lower valve casing 1 is always provided with the lower end portion 15 of the valve body 3 and further the cylinder portion 14,
It is closed by the outer cylinder portion 18 and the like, so that the bottom valve B is closed.

Next, at the time of unloading or loading using a pump, the air-opening / closing bottom valve B is opened as follows from the above-mentioned normally closed state. That is, as shown in FIG. 3, an air chamber 19 formed between the piston 6 and the cylinder portion 14 from an external high pressure air source through an air pipe (not shown), the air pipe 5, the vertical hole H of the piston 6, and the like. When the air is pressed in, the air pressure in the air chamber 19 rises and pushes the valve body 3 upward against the downward biasing force of the spring 4. As a result, the air chamber 19 is expanded upward, the valve body B rises while the inner surface of the cylinder portion 14 is in sliding contact with the piston 6, the spring 4 is compressed, and the lower end portion 15 of the valve body B and the lower valve housing 1 are The pressure contact between the valve seats 9 via the packing 28 is released and separated. The valve body 3 is brought into contact with the cylinder portion 14 under the cap 25 that closes the top surface of the upper valve box 2,
The rise stops. In this way, the valve hole 8 of the lower valve box 1 is released and the bottom valve B is opened. So, tank 1
Due to gravity, the oil or the like loaded in the tank chamber 20 of 0, such as the inflow port 12 of the upper valve casing 2, the opened valve hole 8, the flow passage 21 of the lower valve casing 1, etc. After passing through the bottom valve B and flowing out and passing through the pipe 7, it is unloaded to an underground tank or the like (not shown) on the unloading facility side such as a gas station, or a storage tank on the loading facility side. Oil (not shown) or the like is loaded into the tank chamber 20 of the tank 10 through the pipe 7 and the open bottom valve B using a pump.

Further, when the unloading and loading are completed in this way, the air opening / closing bottom valve B is changed from the above-mentioned opened state shown in FIG.
The closed state shown in is set. That is, the air chamber 1
The air press-fitted in 9 is discharged to the outside through a vertical hole H of the piston 6, an air pipe 5, an air pipe, and the like, from an open port (not shown) that is switched and connected instead of the high pressure air source. Then, the air pressure in the air chamber 19 decreases, and the biasing force of the spring 4 becomes greater, so that the spring 4
Presses the valve element 3 downward while the valve extends. As a result, the air chamber 19 is contracted downward, the valve body 3 is pushed down while the inner surface of the cylinder portion 14 is in sliding contact with the piston 6, and is lowered, and the lower end portion 15 of the valve body 3 is inserted through the packing 28 to the lower valve housing 1 Pressing the valve seat 9 onto the valve seat 3 stops the lowering of the valve body 3. In this way, the valve hole 8 of the lower valve box 1 is closed by the valve body 3, the bottom valve B is closed, the flow of oil or the like is completely cut off, and the above-mentioned closed state is restored.

By the way, in the bottom valve B, as shown in FIGS. 1 and 3, the outer cylinder portion 18 of the valve body 3 is pressed against the inner surface of the upper valve housing 2 via the packing 26 and the wear ring 27. Although it is slidable up and down, in the present invention, the inner surface of such an upper valve box 2 is coated with a resin such as Teflon which is hard and has a small friction coefficient.
Are formed. Therefore, the outer cylinder portion 18, the packing 26, and the wear ring 27 of the valve body 3 can be slid up and down while being pressed against the coating portion C on the inner surface of the upper valve box 2 as described above. Opening and closing bottom valve B of
That is, when the valve body 3 is raised and lowered as a whole, the outer cylinder portion 1 of the valve body 3 is
8, the packing 26, and the wear ring 27 are adapted to slide up and down along the coating portion C on the inner surface of the upper valve body 2 thus coated. Now, in such a tank lorry bottom valve B,
The following are the first, second, third, fourth and fifth.

First, in this bottom valve B, a hard resin having a small friction coefficient such as Teflon is inevitably used for coating the upper valve box 2 side, and the coating portion C formed in this way is used. Is used in combination with, for example, a rubber packing 26 or a resin wear ring 27 on the outer cylinder portion 18 side of the valve body 3. That is, unlike the bottom valve A of this type of conventional example shown in FIG. 4, the packing 26 (16) for sealing on the outer cylinder portion 18 side of the valve body 3 does not necessarily use Teflon or the like. Therefore, packing 26 made of Teflon, etc.
Due to the lack of elasticity of (16), the outer cylinder portion 1 of the valve body 3
8 and the upper valve housing 2 will not lose their sealing ability.

Secondly, in the bottom valve B, the inner surface of the upper valve box 2 is coated with a resin such as Teflon which is hard and has a small friction coefficient, and is pressed against the coating portion C thus formed. As a result, the packing 26 and the wear ring 27 on the outer cylinder portion 18 side of the valve body 3 have small frictional resistance and can be slid smoothly. Therefore, even if the packing 26 made of rubber is used, that is, even if the packing 26 made of rubber having high elasticity and excellent sealing property but a large friction coefficient is used, such packing 26 is pressed and slid. Since the inner surface of the upper valve box 2 is made of a resin coating C such as Teflon which is hard and has a small friction coefficient, the frictional resistance between the two is relatively small and smooth sliding is realized. Therefore, as compared with the bottom valve A of this type of conventional example shown in FIG. 4, the packing 26 and the wear ring 27 on the outer cylinder portion 18 side of the valve body 3 are prevented from being damaged or missing.

Thirdly, in the bottom valve B, the inner surface of the upper valve casing 2 is coated with a resin such as Teflon which is hard and has a small friction coefficient, so that the coating portion C is formed. With respect to itself, finishing of the inner surface and dimensional matching with other components are easily facilitated. That is, like the bottom valve A of this kind of conventional example of FIG. 4 described above, the outer cylinder portion 18 of the valve body 3, its packing 26 (16) and wear ring 27 (17) are made of a light alloy such as aluminum. Since the inner surface of the upper valve box 2 is not directly pressed and slid as it is, it is not necessary to carefully finish the inner surface of the upper valve box 2, and the upper valve box 2 is particularly suitable for other components. Eliminates the need for precise dimensioning.

Fourthly, in the bottom valve B, since the inner surface of the upper valve box 2 is coated with a resin such as Teflon which is hard and has a small friction coefficient, it is pressed against the coating portion C thus formed. As a result, the packing 26 and the wear ring 27 on the outer cylinder portion 18 side of the valve body 3 also have a small friction resistance and can be slid smoothly with a relatively small force. Therefore,
In this air opening / closing bottom valve B, the air press-fitted into the air chamber 19 for opening / closing the bottom valve B by moving the valve body 3 up and down is supplied to the bottom valve A of the conventional example shown in FIG. Compared to
It can be of lower pressure and consume less air.

Fifthly, in the bottom valve B, the inner surface of the upper valve box 2 is finished in a shape smooth by coating such as baking. That is, the finish of the inner surface is not smooth like the above-described conventional example of FIG. 4, that is, when the inner surface of the upper valve box 2 is mechanically finished. It is surely prevented that the uneven shape is formed to be sharp and large. That is, the inner surface of the upper valve box 2 on which the coating portion C is formed by baking or the like has a gentle and small unevenness on the inner surface when viewed in a magnified view with, for example, a microscope. It is finished smoothly.

Therefore, due to such a coating portion C, the frictional resistance between the inner surface side of the upper valve housing 2 and the packing 26 or the wear ring 27 on the outer cylinder portion 18 side of the valve body 3 is small also from this surface. Become. Therefore, the prevention of damage and loss of the second packing 26 and the wear ring 27 described above is further ensured, and the air pressure required to open and close the fourth bottom valve B described above is further reduced. Will be able to.

Here, the functions of the through hole 29 and the oil chamber 30 shown in FIG. 1 and the like will be described. The oil chamber 30 is a space formed between the upper valve box 2 and the valve body 3, that is, the coating portion C on the inner surface of the upper valve box 2 and the cap 2 on the top surface.
5, cylinder portion 14 of valve body 3, lower end portion 15, outer cylinder portion 18
It is composed of a space surrounded by etc., and oil or the like can flow into the inside through the through hole 29. Therefore, with respect to the tank chamber 20 which is not the loading target, in the state where the bottom valve B is closed (see the states described above with reference to FIGS. 1 and 2),
When the bottom valve B of the other tank chamber 20 to be loaded is opened (see FIG. 3, the state described above) and oil or the like is loaded using the pump (so-called bottom loading is performed). In case of), it becomes as follows. In this case, as for the bottom valve B of the tank chamber 20 which is not loaded and is not loaded, the bottom valve B is connected via the pipe 7.
Oil or the like that has been pressure-fed to the valve hole 8 therein causes an upward pressing force to be applied, but this bottom valve B applies the downward urging force of the spring 4 and, in the following manner, ensures that it is closed. It is supposed to be maintained.

That is, the upper valve box 2 forming the oil chamber 30
The diameter and the cross-sectional area of the coating portion C on the inner surface of are set to be much larger than the diameter and the cross-sectional area of the valve seat 9 and the valve hole 8 on the lower valve box 1 side. Therefore, the lower end portion 15 of the valve body 3
The downward pressing force of the oil or the like that has been pumped into the oil chamber 30 from the through hole 29 is much larger than the upward pressing force of the oil or the like near the valve seat 9 or the valve hole 8. . As a result, the valve body 3 is strongly pressed downward, and the lower end portion 15 of the valve body 3 is strongly pressed against the valve seat 9 of the lower valve box 1 via the packing 28, and thus the tank chamber 20 that is not a loading target The bottom valve B surely remains closed. In this way, it is possible to reliably prevent oil or the like from flowing into the tank chamber 20 that is not the loading target via the bottom valve B.

[0040]

As described above, in the bottom valve of the tank truck according to the present invention, a Teflon or the like is formed on the inner surface of the upper valve box where the outer cylinder of the valve body is pressed and slid through the packing and the wear ring. The following effects are exhibited by coating with a hard resin having a small friction coefficient.

First, the sealability between the outer cylinder of the valve body and the upper valve box is excellent. That is, in this bottom valve, Teflon or the like is not necessarily used for the packing on the outer cylinder side of the valve body as in the conventional example of the type described above, but a hard Teflon or the like is used for coating on the upper valve box side. Since a resin with a low coefficient of friction is used, the situation in which the sealability between the outer cylinder of the valve body and the upper valve box is not compromised, and the leakage of gasoline, light oil, kerosene, etc. loaded in the tank chamber does not occur. Avoided.

Secondly, the packing and the wear ring are prevented from being damaged or missing. That is, in this bottom valve, since the inner surface of the upper valve box is coated with a resin such as Teflon that is hard and has a low friction coefficient, the packing and the wear ring on the outer cylinder side of the valve body to be pressure-welded have a friction resistance. It becomes small and smoothly slid, and its damage and loss are prevented,
The life is longer than that of the conventional example of this kind described above.

Thirdly, the finishing and size adjustment of the upper valve box can be simplified and facilitated. In other words, with this bottom valve, the inner surface of the upper valve box itself was coated with a resin such as Teflon that is hard and has a low friction coefficient. However, compared to the above-mentioned conventional example of this kind, it can be simplified easily,
Excellent in cost.

Fourth, it can be opened and closed with a relatively low air pressure. In other words, in this bottom valve, the inner surface of the upper valve housing is coated with a resin such as Teflon that is hard and has a small friction coefficient. The friction resistance is small and smooth sliding can be achieved. Therefore, opening and closing of the bottom valve by raising and lowering the valve element can be performed with lower pressure air compared to the above-mentioned conventional example of this kind, and the air consumption is small. There is.

Fifth, since the inner surface of the upper valve box is finished in a smooth shape, the above-mentioned second and fourth points become more remarkable. That is, in this bottom valve, the inner surface of the upper valve box is finished in a geometrically smooth shape by coating such as baking, and compared with the case where it is mechanically finished as in the conventional example of this kind described above, pressure contact is also made from this surface. , The frictional resistance between the sliding body and the packing or wear ring on the outer cylinder side of the valve body is reduced. Therefore, the above-mentioned second packing and wear ring are prevented from being damaged or lost more reliably, and the above-mentioned fourth opening / closing at a low air pressure is further promoted. As described above, the effects of the present invention are remarkably large, such as the problems existing in this type of conventional example are eliminated.

[Brief description of drawings]

FIG. 1 is a front sectional view of an upper valve box and the like in a closed state, showing an embodiment of a bottom valve of a tank truck according to the present invention.

FIG. 2 is a front sectional view of the lower valve box and the like in the closed state of the same embodiment.

FIG. 3 is a front sectional view of the upper valve box and the like in the open state of the embodiment.

FIG. 4 is a front sectional view of a bottom valve of a conventional tank truck.

FIG. 5 is a side view of the tank truck.

[Explanation of symbols]

 1 Lower Valve Box 2 Upper Valve Box 3 Valve Body 4 Spring 5 Air Pipe 6 Piston 7 Piping 8 Valve Hole 9 Valve Seat 10 Tank 11 Opening 12 Inlet 13 Top Surface 14 Cylinder 15 Bottom End 18 Outer Tube 19 Air Chamber 26 Packing 27 Wear ring B Bottom valve C Coating part

Claims (1)

[Claims] 1. A bottom valve for a tank truck, comprising:
It is equipped with a lower valve box, an upper valve box, a valve body, a spring, an air pipe, a piston, etc., and is an air opening / closing type. The lower valve box is laterally connected to piping and has a valve hole on the upper surface. , A valve seat is provided on the periphery of the valve hole and is fixedly attached to the opening of the tank bottom, and the upper valve box is vertically fixed in the tank from the outside of the valve seat of the lower valve box. The top face is closed and the bottom face is open, and a vertical tubular shape is formed, and an inflow port is formed in the lower part of the side face.The valve body is arranged in the upper valve box so as to be vertically movable, and the top face is A cylindrical cylinder portion which is closed and whose lower surface is opened, a lower end portion which is formed in an outer flange shape at a lower end of the cylinder portion and which can be pressed into contact with a valve seat of the lower valve box, and which is erected from the lower end portion and has an upper portion. Is pressed against the inner surface of the upper valve box via packing and wear ring. An outer cylinder part that is slidable up and down, and the spring is interposed between the closed top surface of the upper valve box and the lower end part of the valve body, and the valve body is connected to the lower part. It is biased toward the valve seat of the valve box, and the air pipe is
Standingly fixed from the lower valve box, the lower part is connected to an external high-pressure air source through an air pipe, and the upper part is coaxially inserted into the cylinder portion of the valve body through the valve hole of the lower valve box, Further, the piston is fixed to the upper portion of the air pipe, is in sliding contact with the inner surface of the cylinder portion of the valve element, and communicates with the upper portion of the air pipe between the closed top surface of the cylinder portion and the like. The inner surface of the upper valve casing, which forms a chamber and in which the outer cylinder portion of the valve body is pressed and slid through the packing and the wear ring, is coated with a resin that is hard and has a small friction coefficient. The bottom valve of the tank tank that features.