JPS604104Y2 - Loading arm liquid level detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liquid level detection device for a loading arm used for handling liquids (hereinafter referred to as liquids) such as petroleum and gasoline.

Conventionally, the liquid is stored in a tank by a loading arm,
When loading a tank truck (hereinafter referred to as a tank), a predetermined amount of liquid was measured and loaded using a meter.
If the above quantitative meter malfunctions or if liquid remains in the tank before loading, the liquid may rise above the standard level of the tank, resulting in overfilling and even overflowing from the hatch. Therefore, workers had to constantly monitor the amount of cargo in the tank from outside the hatch.

However, during loading of the liquid, a portion of the liquid vaporizes due to the flow of the liquid, and the vapor that fills the space inside the tank is released from the hatch into the atmosphere, which not only poses a safety problem. It was also harmful to the health of workers.

Therefore, in recent years, a device has been proposed in which the hatch is shielded during liquid loading and vapor is recovered through a discharge pipe.1. In this case, since the amount of liquid loaded cannot be monitored from outside the hatch, the above-mentioned problems such as overfilling and overflow have come to the fore again.

This invention was made to solve the above problem.
It is an object of the present invention to provide a liquid level detection device for a loading arm that can prevent overfilling, overflow, etc. even if the hatch is filled with liquid while being shielded during liquid loading.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings showing embodiments thereof.

In FIG. 1, reference numeral 1 denotes a plug provided at the tip of a conventionally known loading arm, and a drop pipe 2 is slidably passed through the plug.

The blockage plug 1 consists of a sealing member 3 whose inner end surface is slidably attached to a drop pipe 2, and a spherical forest-like sealing plate 5 fixed to the lower part of the sealing member 3. A sealed chamber 6 is formed by the seal plate 5 and the sealed chamber 6.
is connected to a vapor processing device (not shown) via an exhaust pipe 7.

Further, there is a gap between the lower end of the seal plate 5 and the drop pipe 2, and this gap serves as a vapor suction port.

The outer surface of the seal plate 5 is coated with an elastic material 8 such as rubber, which prevents sparks from being generated due to impact when the seal plate 5 contacts the hatch H of the tank T.

A fixture 9 for crimping the sealing member 3 to the drop pipe 2 is attached to the upper part of the plug 1, and a plurality of support pipes 10, 11 are vertically installed at the lower part.

A support ring 21 surrounding the outer peripheral surface of the drop pipe 2 is fixed to the lower end of the support pipe 10, 11, and prevents the drop pipe 2 from swinging laterally.

One of the support pipes 10 and 11 also serves as a detection tube having a structure as shown in FIG.
is fixed by screwing into the sealing member 3 a threaded portion 12 provided on the outer surface of the upper part.

The outer cylinders 13a and 13b of the detection tube 11 are made of a non-magnetic material, and have two openings 14 and 15 at the top. The lower opening hole 15 communicates with the type alarm 23 and communicates with the atmosphere through the exhaust hole 4 of the sealing member 3.

A thin tube 16 is fixed inside the detection tube 11, and the upper part of the detection tube 11 is divided into two parts by the thin tube. The external chamber communicates with the lower opening 15 .

A movable member 17 made of a magnetic material is provided below the thin tube 16 so as to be able to move up and down. In normal conditions, the movable member 17 is urged upward by a coil spring 18, and a shaft portion 17a protruding from the upper end of the thin tube 16 The lower end opening (communication port) 16a is substantially closed.

Note that 17b is a permanent magnet attached to the lower surface of the movable member 17.

A float 19 having a permanent magnet 19a attached to its upper surface is housed in the lower chamber of the detection tube 11 so as to be movable up and down, and a coil spring 20 is placed on the upper surface of the float 19.

The upper and lower surfaces of both the magnets 17b and 19a are magnetized with different polarities, respectively, so that when the two magnets approach within a predetermined distance, they overcome the repulsive force of the coil springs 18 and 20 and rapidly attract each other. ing.

Note that either the permanent magnet 17b of the movable member 17 or the permanent magnet 19a of the float 19 may be made of a magnetic material such as a piece of iron, but it is better to make both permanent magnets so that the movable member 17
His movements are sharp.

Further, the coil spring 20 on the upper surface of the float 19 is provided for the following reason.

That is, if the weight of the float 19 is reduced to increase its buoyancy, when the liquid level drops after the permanent magnets 17b and 19a are attracted, the friction between the float 19 and the inner surface of the detection tube 11 or the viscous resistance of the liquid causes The float 19 will no longer move downward easily.

Therefore, the repulsive force of the coil spring 20 is used to forcibly separate the permanent magnets 17b and 19a to ensure that the float 19 moves downward.

The pneumatic alarm 23 roughly consists of an inverter 24, an amplifier 25, and a horn 26. The inverter 24 is divided into two upper and lower chambers by a diaphragm 24a, and the lower chamber is further divided into two chambers by a protruding valve seat 24e. 24c.

It is divided into 24d.

The upper chamber 24b communicates with the upper opening hole 14 of the detection tube 11 through piping 22, and the lower chamber 24c communicates with the pressure reducing valve 28 through piping 27.
It communicates with a supply air source 29 via.

Further, air from the supply air source 29 passes through a pipe 32 branched from the pipe 27 and flows into the pipe 22 via a pressure reducing valve 30.

Therefore, the thin tube 1 of the detection tube 11 communicating with the piping 22
A small amount of air always leaks from the lower end opening 16a, and this air flows out from the opening hole 15 below the detection tube 11 into the atmosphere.

The amplifier 25 has three diaphragm chambers arranged vertically, each having a valve body 33b, 34b, 35b, diaphragms 33a, 34a, 35a, a valve seat 33e,
34e and 35e are provided.

The upper chamber 33c of the diaphragm chamber 33 communicates with the lower chamber 24d of the inverter 24 through a pipe 31, and the lower chamber 33d of the upper diaphragm chamber 33 communicates with the supply air source 29 (1 to 5 ko/cJ) through a pipe 37 having an orifice 36. It communicates with the air and is always open to the atmosphere.

The upper chamber 34c of the middle diaphragm chamber 34 of the amplifier 25 is connected to the piping 3 together with the lower chamber 33d of the upper diaphragm chamber 33.
7, the lower chamber 34d communicates with the upper chamber 35c of the lower diaphragm chamber 35, and is always open to the outside air.

The valve body 34b of the middle diaphragm chamber 34 is connected to the valve body 35b of the lower diaphragm chamber 35 by a rod 38.

The upper chamber 35c of the lower diaphragm chamber 35 communicates with the air source 29 through a piping 39, and the horn 26 through a piping 40 that opens one end into the valve seat 35e, and the lower chamber 35d communicates with the air source 29 through a piping 40.
1 communicates with the air source 29, and has a compression spring 42 that always urges the valve body 35b upward.

Under normal conditions, the two valve seats 33e and 34e of the upper and middle diaphragm chambers 33 and 34 of the amplifier 25 are open, and only the valve seat 35e of the lower diaphragm chamber 35 is closed by the repulsive force of the spring 42. ing.

Next, the operation of the liquid level detection device having the above configuration will be explained.

First, the loading arm is moved above the tank T, and the drop pipe 2 is inserted into the tank T through the hatch H.

When the drop pipe 2 is inserted, the elastic member 8 on the lower surface of the plug 1 comes into contact with the hatch H, and then only the drop pipe 2 enters the tank T, and its tip reaches the bottom of the tank T and stops.

A valve (not shown) is then opened and the liquid is loaded into the tank T through the drop pipe 2.

At this time, the vapor filling the tank T is pushed upward by the liquid and is discharged from the sealed chamber 6 via the exhaust pipe 7 and sent to a vapor processing device (not shown).

Now, when the liquid level in the tank T rises and reaches the bottom of the detection tube 11, the float 19 begins to move upward, and the coil spring 20
comes into contact with the upper surface of the lower chamber.

Further, when the float 19 moves upward due to buoyancy, the coil spring 20 is compressed, and when the distance from the movable member 17 becomes less than a predetermined value, the movable member 17 suddenly moves against the coil spring 18 due to the attractive force of both magnets 17b and 19a. The shaft portion 17a opens the lower end opening 16a of the thin tube 16.

Then, air from the air source 29 communicated via the pipe 22 is blown out from the lower end opening 16a of the thin tube 16, and the internal pressure of the pipe 22 is rapidly reduced.

As a result, the pressure in the upper chamber 24b of the inverter 24 decreases, the diaphragm 24a is inverted upward, and the lower chamber 24c*2
4d communicates.

The air supplied from the pipe 27 is passed through the pipe 31 to the amplifier 25.
It flows into the upper chamber 33c of the upper diaphragm chamber 33, and the valve body 33b moves downward to close the valve seat 33e and open the orifice 3.
6, the supply air communicates with the upper diaphragm chamber 33.
It does not flow into the lower chamber 33d, but flows into the upper chamber 34c of the middle diaphragm chamber 34.

As a result, the valve body 34b is pushed down against the repulsive force of the spring 42, and the valve seat 34e is closed. At the same time, the valve body 35b, which is integrated with the valve body 34b,
5 is opened, compressed air from the air source 29 is sent to the horn 26, and the horn 26 is sounded to notify the operator that the liquid level has reached a predetermined position.

Incidentally, since the position of the liquid level to be detected may change depending on the size of the hatch H, etc., the detection tube 11 may be made to be able to slide up and down with respect to the plug 1 according to this change.

In the above embodiment, the pneumatic alarm 23 was used as the liquid level detection device, but instead, an automatic closing device that automatically closes the valve depending on the internal pressure change of the piping 22 may be used. Well, then the operator does not need to be in the vicinity of the tank T during loading.

In addition, in the above embodiment, the detection of the liquid level position when storing liquids such as oil or gasoline in a tank was described, but the present invention is not limited to this, and the present invention is also applicable to liquid level detection when loading other liquids. Of course, it can also be applied to

As is clear from the above description, the liquid level detection device according to the present invention uses air as an operating source to detect the liquid level without using any electrical equipment, and is therefore suitable for detecting the level of explosive liquids. It is.

In particular, when an explosive liquid such as gasoline is loaded into a tank, a large amount of vapor is generated, and if air gets mixed into the tank and the ratio of vapor to oxygen reaches a certain range, an extremely explosive atmosphere can occur. , there is a risk that the so-called explosion may become a concern.

In the present invention, the hatch of the tank is closed with a stopper, and all the air blown from the air supply pipe through the communication port is released outside the tank, so the inside of the tank does not feel like an explosion and is safe.

In addition, in a closed container such as a tank, as liquid is loaded, the pressure inside the tank increases, and this pressure change may affect the internal pressure of the air supply pipe, causing the alarm to malfunction. Since the inside of the detection tube is completely isolated from the inside of the tank, the operating value is completely unaffected by changes in the pressure inside the tank.

Furthermore, the operating mechanisms such as movable members and floats are housed vertically within a single detection tube that also serves as a support pipe, making it extremely compact and does not get in the way when inserting the drop pipe into the hatch. Since the movable member is protected on the outside by the detection tube, there is no need to worry about it being damaged by being hit by a hatchet or the like.

In addition, a spring material is provided on the upper surface of the float to urge the float downward, so even if the weight of the float is reduced, problems such as the inability of the float to move downward due to frictional force with the inner surface of the detection tube and viscous resistance of the liquid are avoided. The float can be reliably returned to its downward motion without causing any damage.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of a liquid level detection device according to the present invention;
FIG. 2 is a sectional view of the detection tube, and FIG. 3 is a schematic explanatory diagram of the pneumatic alarm when it is not in operation.

Claims (1)

[Scope of utility model registration request] In a loading arm, in which a plurality of support pipes are installed vertically on a plug that closes a tank hatch, and a support ring that guides the outer circumference of a drop pipe is attached to the lower end of the support pipe, one of the support pipes is installed. is a detection tube made of a non-magnetic material, the upper part of the detection tube is divided into two parts,
The chamber is opened to the outside of the tank, and an air supply pipe that communicates with the pneumatic alarm means is connected to another chamber, while the communication port between the two chambers is closed in the center of the detection tube by the biasing force of a spring material. A movable member is housed so as to be movable up and down, a float is housed at the bottom of the detection tube so as to be movable up and down, and a permanent magnet is provided on one of the lower surface of the movable member and the upper surface of the float, and the other is attracted to the permanent magnet. A magnetic material or a permanent magnet is provided on the upper surface of the float, and a spring material is provided on the upper surface of the float that urges the float downward and has a spring force smaller than the adsorption force of the permanent magnet, so that the float reaches a predetermined position along with the liquid level in the tank. Loading characterized in that when the movable member rises, it is sucked downward against the biasing force of the spring material to open the communication port, thereby lowering the internal pressure of the air supply pipe and activating the pneumatic alarm means. Arm liquid level detection device.