JPH0159192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overflow prevention device that prevents liquid overflow due to malfunction or erroneous operation of equipment such as liquid cargo handling equipment when handling liquids such as petroleum to tank trucks or tank wagons.

When loading petroleum such as gasoline, kerosene, diesel oil, or other liquids into the tank (receiving tank) of a tank truck or tank wagon using a loading arm (liquid handling device), the amount of liquid loaded into the tank. is set in advance and loading is started, and when the preset loading amount is reached, the main valve installed upstream of the loading arm automatically closes, but due to equipment failure or incorrect operation, liquid may overflow from the tank. In such cases, especially petroleum overflows create an atmosphere of dangerous gases,
In addition, there were many tank trucks and tank wagons coming and going near cargo handling facilities, and the engines of these vehicles could become a source of ignition, so one wrong move could lead to a major disaster.

Therefore, conventionally, as shown in FIG. 7, an overflow prevention device 2 was attached to the loading arm 1. This overflow prevention device 2
This prevents overflow from the tank 3 without using an external drive source such as an electric source or compressed air source. During normal liquid cargo handling, the main valve (valve) 4 is closed as shown in Figure 8. When the pilot valve 5 is opened, the needle 6 and the ball 26 are opened.
The main valve 4 and the pilot valve 5 are restrained by a restraining mechanism 7 consisting of the like, and the main valve 4 and the pilot valve 5 are fixed in the open state, and the liquid is supplied into the tank 3 through the drop pipe 8. Also, at this time, since the flow divider valve 10 is open, liquid flows through the flow divider pipe 9 and the bench lily 11, and the bench lily 11 sucks air from the negative pressure pipe 9b, but the valve 12 is always open and the sensor section 13, the upper chamber 15 of the diaphragm 14 does not have a negative pressure and the lower chamber 16
maintains an equal pressure state. On the other hand, if the liquid level in the tank 3 rises above a predetermined level due to equipment failure or erroneous operation, the open end 9a of the negative pressure pipe 9b is blocked and the upper chamber 1 of the diaphragm 14 is closed, as shown in FIG.
5 is sucked in by the bench lily 11 and becomes negative pressure, the needle 6 rises and the restraint of the pilot valve 5 is released, and the pilot valve 5 and the main valve 4 are sequentially closed by the biasing force of the spring 17 as shown in FIG. 10. (A similar device is Utility Model Application No. 58-125199.) However, in the above-mentioned overflow prevention device 2, if the flow rate of the liquid flowing in the loading arm 1 is small, the flow rate of the liquid flowing in the bench lily 11 becomes small. However, there was a drawback in that the bench lily 11 could not provide sufficient negative pressure to release the pilot valve 5 from its fixation.

In order to compensate for this drawback, we changed the valve structure to a hydraulic valve (a valve that opens the valve using the differential pressure between the pressure on the upstream side and the pressure on the downstream side of the valve), and incorporated the above-mentioned bench lily into the overflow valve. There are oil supply devices with a prevention function, but since the valve closes when the flow of liquid stops, the oil supply device is always filled with liquid, which has the following drawbacks.

(1) There is a risk of liquid leakage.

(2) When the outside temperature rises, there is a risk that the liquid inside the device will expand and the pressure inside the device will become abnormally high.

(3) The loading arm 1 is normally operated by one worker, but since the weight of the liquid is added, the weight of the loading arm 1 in the above device is lower than that of other conventional types. If the diameter of the tube is 4 inches, it will be 1.5 to 2.0 times as large, making it extremely difficult to operate.

The present invention was made in view of the above circumstances, and
A liquid that operates reliably regardless of the flow rate of the liquid flowing inside the liquid cargo handling device, and since no liquid remains inside the liquid cargo handling device, it is safe with no risk of leakage, etc., and has good operability. The purpose of this invention is to provide an overflow prevention device for cargo handling equipment, etc.

In order to achieve the above object, the present invention provides a housing having an inlet and a discharge port, and a housing that is provided in the housing so as to be vertically movable, and in a lowered state, the communication between the inlet and the discharge port is cut off, and in a raised state, the inlet is inhaled. A main valve that communicates a discharge port with a mouth, a main diaphragm that partitions the inside of the housing into a first upper chamber and a first lower chamber and is provided to support the main valve, and a shaft hole that opens at the upper and lower parts. and the above-mentioned first
A pilot valve provided in the upper chamber and in contact with the upper surface of the main valve to close the communication hole of the main valve, a spring that biases the pilot valve downward, and a second upper chamber and a second upper chamber provided in the upper part of the housing. A second diaphragm stretched to partition the lower chamber; A needle is provided vertically on the second diaphragm, and a needle is provided on the upper part of the pilot valve so as to be movable in the radial direction of the pilot valve, and when the pilot valve is raised, the tapered part of the needle causes the outer side of the housing to extend upwardly on the inclined surface. A plurality of balls are pushed out and restrain the free downward movement of the pilot valve, and a plurality of balls are inserted into the shaft hole of the pilot valve so as to be able to move up and down, and when rising, the needle is moved upward to release the restraint of the pilot valve by the balls. Rod and
a shaft provided with a pressing pin and rotatable in the circumferential direction of the housing; a lever having its tip locked with the pilot valve and freely fitted to the shaft; and a lever fixed to the shaft and rotatably mounted on the shaft. a cam plate that comes in contact with the lever and rotates the lever when rotated at a predetermined angle; , a link for raising the rod, a drop pipe attached to the discharge port of the housing, and a cylindrical part in the lower part with through holes formed in the upper part, lower part, and side part, and an inlet in the upper part. an attached detection tube, and a float that is formed to have a larger diameter than the through hole, is inserted into the cylindrical part so as to be able to move up and down, and floats up with the liquid that has entered the cylindrical part to close the upper through hole. and a communication tube whose lower end is disposed between the inflow port and the cylindrical portion, inserted into the detection tube, and communicated with the second lower chamber.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the figures, reference numeral 20 indicates that the end of the outboard arm 1a of the loading arm 1 is connected to the side suction port 20a in a downward direction. A drop pipe 8 is connected to each discharge port 20b of the housing. Inside the housing 20, as in the conventional case, there is a main valve 4 that opens and closes a flow path in the housing 20, and an upper chamber 2 that connects an upstream flow path partitioned by the main valve 4.
The main diaphragm 23 has a main diaphragm 23 partitioned into a lower chamber 22 that communicates with the main valve 1 and the suction port 20a, and a shaft hole 5a at the center. It is raised by the handle 25 via the mechanism 24, and communicates the upper chamber 21 and the downstream flow path 4c through the communication hole 4b of the main valve 4, and also moves the main valve 4 upward from the middle of the rise. A pilot valve 5 is provided which is pushed to an open state, is urged downward by a spring 17 to cut off communication between the upper chamber 21 and the flow path 4c, and is pushed down to close the main valve 4 when descending. ing. The clutch mechanism 24 includes a shaft 24a connected to the handle 25 and a pin (pressing pin) 24 fixed to the shaft 24a.
b and the cam plate 24e are fitted to the shaft 24a so as to be relatively rotatable, and the tip thereof is connected to the pilot valve 5.
and a lever 24c engaged with the lower end of the
When the lever 24c opens the main valve 4 with the handle 25, the cam plate 24e abuts against the cam surface 24g formed on the end surface of the lever 24c at a predetermined clockwise rotation position of the shaft 24a in FIG. The lever 2 rotates integrally with the shaft 24a to push up the pilot valve 5 and close the main valve 4.
4c is in a locked state, and only the shaft 24a can rotate counterclockwise in FIG. Further, a plurality of balls 26 are provided on the upper side of the pilot valve 5.
(only one is shown in FIG. 2) is allowed to move in the radial direction of the pilot valve 5 and is locked,
Moreover, at the upper position of the pilot valve 5, there is a tapered part 6a which becomes smaller in diameter as it goes downward to the middle part.
The needle 6 is formed with a diameter 6b smaller in diameter than the shaft hole 5b in the upper part of the pilot valve 5 on the lower end side.
is arranged, and at the upper end of the needle 6,
A diaphragm 14 urged downward by a spring 27 is provided to partition an upper chamber 15 and a lower chamber (operating chamber) 16. And pilot valve 5
is raised by the handle 25 via the clutch mechanism 24, the pilot valve 5 initially
Next, the main valve 4 is opened, and the tip of the detail 6b of the needle 6 is inserted into the shaft hole 5 of the pilot valve 5.
b, and the ball 26 at the top of the pilot valve 5
However, the tapered part 6a of the needle 6 and the housing 20
The inside of the ball 26 is in contact with the tapered part 6a of the needle 6, and the inner half is in contact with the pilot valve 5, and the outer half is in contact with the inclined surface 20 of the housing 20.
The ball 26 and the needle 6 constitute a restraining mechanism 7. Further, a rod 28 is inserted into the shaft hole 5a of the pilot valve 5, and when the handle 25 is operated to open the main valve 4, the rod 28 is connected to a link 29 rotatably supported by the lever 24c. When the handle 25 is operated to close the main valve 4, a pin 24b fixed to the shaft 24a of the clutch mechanism 24 contacts the base end of the link 29, and as a result, the link 29 is rotated clockwise about the pin 29a in FIG. , the needle 6 is pushed upward. On the other hand, in the holder 8a of the drop pipe 8, a detection tube 31 having a liquid inlet 30 at a predetermined position has one open end (upper end) 31a attached to the holder 8a. 8a (the inlet 30 may not be provided, and the open end (upper end) 31a may be located at a predetermined height), and the other end (lower end) 31b is located at a predetermined height (quantitative amount) of the tank 3. The other end 31b of the detection tube 31 is provided with through holes 32a, 32b, 32 of a predetermined diameter in the upper, lower and side parts.
The cylindrical portions 32 each having a diameter of
A spherical float 33 with a larger diameter is inserted. When the cylindrical portion 32 is immersed in the liquid, the liquid flows into the cylindrical portion 32 from the through holes 32b and 32c in the lower and side portions, and the float 33 rises due to the buoyancy of the liquid, causing the float 33 to rise above the upper portion. The through hole 32a is closed and the other end 31b of the detection tube 31 is closed, while when the cylindrical portion 32 is pulled out of the liquid, the liquid inside the detection tube 31 passes through the upper and side through holes 32a and 32c in sequence. When the liquid level in the tank 3 exceeds the predetermined height, the liquid passes through the inlet 30 and is discharged from the detection tube 3.
1.

Furthermore, inside the detection tube 31, one end (upper end) is provided.
A communication pipe 34 whose 34a communicates with the lower chamber 16 of the diaphragm 14 via a tube 35 is disposed with the other end (lower end) 34b located below the inflow port 30. The diaphragm 14 is adapted to be actuated by the positive pressure of the liquid generated therein.

In the overflow prevention device configured as described above, when the handle 25 is operated, the lever 24c is rotated upward by the cam plate 24e fixed to the shaft 24a of the clutch mechanism 24, the pilot valve 5 is pushed up, and at the same time the link The rod 28 in contact with the rod 29 is also pushed up, and the pilot valve 5 opens first. When the pilot valve 5 opens, the upper chamber 2
The liquid in the main valve 1 flows downward through the communication hole 4b, and the main diaphragm 23 is bent upward by the liquid pressure to raise the main valve 4 and open the flow path. The stepped portion formed at the lower end of the shaft of the pilot valve 5 presses the main valve 4 upward after the pilot valve 5 has risen a little, thereby helping the main valve 4 to open. As the pilot valve 5 rises, the lower end of the detail 6b of the needle 6 enters the shaft hole 5b of the pilot valve 5, and the ball 26 is guided by its tapered portion 6c and the inclined surface 20c of the housing 20 and pushed outward. This pushed-out ball 26 restricts the free downward movement of the pilot valve 5. If the liquid level has not reached the detection tube 31, the float 33
As shown in the figure, the through hole 32b at the bottom of the cylindrical part 32 is closed, but as the liquid is loaded and the liquid level rises and the cylindrical part 32 is immersed in the liquid, Liquid flows into the through holes 32b and 32c in the lower and side portions of the cylindrical portion 32. and,
As shown in FIG. 4b, the float 33 rises due to buoyancy and closes the through hole 32a in the upper part of the cylindrical portion 32, so that no liquid flows into the detection tube 31. Even if it were to flow in, it would only be a small amount of liquid, so no positive pressure would be generated.

On the other hand, when the amount of liquid in the tank 3 reaches a predetermined amount,
When the equipment is operating normally, the main valve upstream of loading arm 1 closes based on the detection signal from the flow meter (not shown) and the liquid supply is automatically stopped. However, if the equipment malfunctions or If the main valve does not close due to an erroneous operation and the liquid level in the tank 3 rises above a predetermined height, liquid will flow into the detection tube 31 from its inlet 30, causing the communication tube to open as shown in Figure 4c. A positive pressure of rhmmAq is generated within 34. Here, r
is the specific gravity of the liquid, and h is the difference between the liquid level in the tank 3 and the liquid level in the communication pipe 34. By this positive pressure, the pressure in the lower chamber 16 of the diaphragm 14 is higher than the pressure in the upper chamber 15, which is open to the atmosphere, and this pressure difference causes the diaphragm 14 to curve upward and become springy. The needle 6 is pushed up against the urging force of the pilot valve 5, and the inside of the ball 26 comes into contact with the detail 6b of the needle 6, and the outside of the ball 26 is pushed inward from the upper outer periphery of the pilot valve 5. The fixation of the pilot valve 5 is released. The pilot valve 5 is pushed down by the biasing force of the spring 17, and in conjunction with this, the main valve 4 is closed to prevent liquid from overflowing from the tank 3.

In addition, in the normal case where the main valve upstream of the loading arm 1 is closed and the supply of liquid is automatically stopped and the loading work of the liquid is completed, the loading arm 1
When the remaining liquid has been drained, return the handle 25. Then, the shaft 24 of the clutch mechanism 24
a rotates relative to the locked lever 24c, and the pin 24b of the shaft 24a abuts the base end of the link 29, causing the link 29 to rotate clockwise relative to the pin 29a in FIG. Since it is rotated, the rod 28 is connected to the pilot valve 5 via the link 29.
The needle 6 is pushed up relative to the needle 6, the ball 26 is pushed inward, the fixation of the pilot valve 5 is released, and the pilot valve 5 is pushed down by the elasticity of the spring 17. The main valve 4 lowers and closes.

In this way, the overflow prevention device described above has the following features: (1) Since the positive pressure of the liquid generated in the communication pipe 34 is utilized, the diaphragm 14 can be reliably pressed regardless of the flow rate of the liquid flowing inside the loading arm 1. can be activated to prevent overflow.

(2) Since the main valve 4 is not opened or closed by liquid pressure, its opening degree can be increased to quickly drain the remaining liquid in the loading arm 1. Therefore, it takes less time to drain the remaining liquid. It can be shortened to within 2 to 3 seconds.

(3) Since no liquid remains in the loading arm 1 after cargo handling is completed, there is no risk of liquid leakage or increase in internal pressure, resulting in high safety. In addition, the entire loading arm 1 is light, has extremely good operability, and is safe even when working at high places on a tank truck or the like.

(4) No need for the conventional bench lily 11,
Since there is no need to provide the flow divider pipe 9, flow divider valve 10, etc., the structure is extremely simple and easy to manufacture.

(5) Products using conventional Benchlily 11 are liquids with high viscosity (generally liquids of 5 to 7 CP or more).
However, the above device can be used with high viscosity liquids without any problems.

(6) Since the detection tube 31 is fitted to the outside of the communication tube 34 to create a double tube structure, positive pressure is applied to the lower chamber 16 of the diaphragm 14 only when liquid overflows.
Therefore, there is no malfunction and high reliability. If only the communication pipe 34 were used, positive pressure would act on the lower chamber 16 even during normal loading, pushing the diaphragm 14 up.
Easy to malfunction due to vibration, etc.

(7) Even if liquid flows into the detection tube 31 at the time of overflow, the float 33 falls when the drop pipe 8 is pulled out from the tank 3, so the liquid is discharged to the outside through the through holes 32a and 32c. Furthermore, even if rain accumulates inside the detection tube 31 when the above device is not in use, it will be discharged to the outside through the through holes 32a and 32c.
Don't worry too much about malfunctions.

By the way, when handling volatile liquids such as gasoline or liquids that generate bad odors, as shown in FIG. The rubber stopper 36 may be closed and the gas recovery pipe 37 connected to the rubber stopper 36.
The internal pressure within the tank 3 increases during liquid handling. Therefore, in this case, the inner space of the rubber stopper 36, which has the same pressure as the pressure inside the tank 3, and the upper chamber 15 of the diaphragm 14 may be interconnected by a pressure equalizing pipe 38, as shown in the drawing.

Furthermore, when handling petroleum, the lower end of the drop pipe 8 must always reach the inner bottom of the tank 3 in order to prevent the generation of static electricity. Even if the size of the tank 3 is different, it is necessary to ensure that the holder 8a of the drop pipe 8 is seated in the receiving port of the tank 3. For this reason, the drop pipe 8 usually has a telescoping double pipe structure, but as shown in FIG. In this way, there is no need for the drop pipe to have a telescopic double pipe structure, and the structure becomes simpler. In addition,
In the figure, 39a and 39b are upper and lower limit stopper members, respectively.

As explained above, an overflow prevention device such as a liquid cargo handling device of the present invention includes a housing provided with an inlet and a discharge port, and a housing that is provided in the housing so as to be vertically movable so that the inlet and the discharge port are connected to each other in the lowered state. a main valve that cuts off the communication and communicates the discharge port with the suction port in a raised state; a main diaphragm that partitions the inside of the housing into a first upper chamber and a first lower chamber and is provided to support the main valve; a pilot valve that is provided in the first upper chamber and has a shaft hole that opens at the bottom thereof and that contacts the upper surface of the main valve to close the communication hole of the main valve; and a spring that urges the pilot valve downward. , a second diaphragm extending over the upper part of the housing to partition a second upper chamber and a second lower chamber; A needle is provided vertically on the second diaphragm so as to be freely inserted into the upper shaft hole of the pilot valve; A plurality of balls are inserted into the shaft hole of the pilot valve so as to be freely moved up and down, and the needle is inserted into the shaft hole of the pilot valve so as to move up and down. a rod that moves the valve upward to release the restraint of the pilot valve by the ball; a shaft that is provided with a press pin and is rotatable in the circumferential direction in the housing; a lever that is freely fitted, a cam plate that is fixed to the shaft and contacts the lever and rotates the lever when the shaft rotates at a predetermined angle; and a cam plate that is rotatably provided on the lever with a pin and that presses the lever. A link whose base end is pushed by the pin and rotates around the pin to raise the rod, a drop pipe attached to the discharge port of the housing, and through holes formed in the top, bottom, and sides. A detection tube having a cylindrical portion at the bottom and an inlet at the top and attached to the drop pipe, and a detection tube formed with a larger diameter than the through hole and inserted into the cylindrical portion so as to be able to move up and down and enter the cylindrical portion. a float that floats up due to the liquid and closes the upper through hole; and a communication tube that is inserted into the detection tube with its lower end disposed between the inflow port and the cylindrical portion and communicated with the second lower chamber. Since the structure includes the following, the effects (1) to (7) above are achieved.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a half-sectional view, FIG. 2 is an enlarged sectional view of FIG. 1, and FIG. 3A is an enlarged sectional view of FIG. FIG. 3B is a cross-sectional view taken from FIG. Further, FIGS. 5 and 6 are sectional views showing other embodiments, FIG. 7 is a schematic diagram of a loading arm, and FIGS. 8 to 10 are sectional views of a conventional device. 4... Main valve (valve), 5... Pilot valve, 6...
... Needle, 7 ... Restriction mechanism, 16 ... Lower chamber (operating chamber), 31 ... Detection tube, 33 ... Float,
34...Communication pipe.

Claims (1)

[Claims] 1. A housing 20 provided with an inlet 20a and an outlet 20b, and a housing 20 that is provided in the housing 20 so as to be vertically movable, and in a lowered state, the communication between the inlet 20a and the outlet 20b is cut off, and in an elevated state, the inlet 20a is provided with an outlet. 20b, a main diaphragm 23 that partitions the inside of the housing 20 into a first upper chamber 21 and a first lower chamber 22 and is provided to support the main valve 4, and a main diaphragm 23 that is open at the upper and lower parts. A pilot valve 5 is provided with shaft holes 5b and 5a, and is provided in the first upper chamber 21 and closes the communication hole 4b of the main valve 4 by contacting the upper surface of the main valve 4.
and a spring 17 that urges the pilot valve 5 downward.
A second upper chamber 15 is provided in the upper part of the housing 20.
and a second diaphragm 14 stretched to partition the second lower chamber 16, and the lower part is a detail 6b.
a needle 6 which is vertically disposed on the second diaphragm 14 and has a tapered part 6a extending upwardly on the second diaphragm 14 so that the detail 6b can be freely inserted into the upper shaft hole 5b of the pilot valve 5; It is provided on the upper part of the pilot valve 5 so as to be movable in the radial direction of the pilot valve 5. When the pilot valve 5 is raised, the outer part is pushed out by the tapered part 6a of the needle 6 onto the upwardly expanding inclined surface 20c of the housing 20, and the pilot valve 5 is moved upwardly. A plurality of balls 26 that restrict free movement downward, and shaft holes 5a, 5b of the pilot valve 5.
The needle 6 is inserted vertically freely into the
by moving the valve upward to open the pilot valve 5 using the ball 26.
a shaft 24a provided with a pressing pin 24b and rotatably provided in the circumferential direction of the housing 20; The combined lever 24c is fixed to the shaft 24a and the shaft 2
A cam plate 24e contacts the lever 24c and rotates the lever 24c by rotating the lever 4a at a predetermined angle, and a cam plate 24e is rotatably provided on the lever 24c with a pin 29a and has its base end pushed by the pressing pin 24b. pin 29
a link 29 that rotates around a and raises the rod 28; and a discharge port 20 of the housing 20.
The drop pipe 8 is attached to the drop pipe 8, and has a cylindrical part 32 at the lower part in which through holes 32a, 32b, and 32c are formed in the upper, lower, and side parts, and an inlet 30 at the upper part, and is attached to the drop pipe 8. The detection tube 31 and the through holes 32a, 32
a float 33 which is formed to have a larger diameter than the cylindrical portions b and 32c and is inserted into the cylindrical portion 32 so as to be able to move up and down, and which floats due to the liquid that has entered the cylindrical portion 32 and closes the upper through hole 32a; 34b is disposed between the inlet port 30 and the cylindrical portion 32, and a communication pipe 34 is inserted into the detection tube 31 and communicated with the second lower chamber 16. overflow prevention device.