When the tanker is filled, the reason why it cannot be filled in;

1. The pressure inside the car is too high;

2. Pipeline valve and tank car shut-off valve are not open;

3. The spot valve is frozen and blocked;

4. The loading pump is evacuated.

Processing method:

1. Pressure relief, reduce the pressure in the tank car;

2. Identify the position and open the valve;

3. Find out the reason and deal with it by means of steam purging;

4. According to the pump evacuation processing procedures for processing.

Reasons for over-filling of tanker;

1. Failure of level gauge;

2. After filling, the pump is not stopped and the valve is not closed in time;

3. The pull-out height of the sliding pipe level gauge is incorrect;

4. Use the highest liquid level control valve of the tank car for metering.

Processing method:

1. Handle the level meter and pour out the excess part;

2. After filling, stop the pump, close the valve and pour out the excess part in time;

3. When filling, carefully check the pull-out height of the sliding tube level gauge and pour out the excess part;

4. It is strictly prohibited to use the highest liquid level control for measurement, and pour out the excess part according to the filling amount of the tank car.

slide level gauge

Slide tube liquid level gauge is by means of the valve outlet to spray liquid or gas medium, through the sliding tube to pull out the height, into the container medium (when the liquid level reaches the lower end of the sliding tube) volume of a safety device.

1. Purpose

The sliding tube level gauge is suitable for various automobiles, railway tankers, solid storage tanks and other equipment that store and transport liquefied petroleum gas, liquid ammonia and other media. The liquid level height of the liquid in the container can be measured by the sliding tube level gauge, which can control the filling volume of the medium. It is a reliable device for medium control and safe transportation of liquefied gas tankers.

2. Technical characteristics

Take HGY----25 type liquid level gauge as an example, its technical characteristics are shown in the following table

Project Unit Parameters

Nominal pressure Kgf/cm 25

Nominal caliber mm 3

Maximum slide-out height of slide tube mm 1400

Effective working height of slide tube mm 0 --- 1000

Applicable medium liquid ammonia, liquefied petroleum gas

Accuracy Class

3. Structure and characteristics

1) the structure;

The sliding tube level gauge is mainly composed of body, valve body, valve flap, sliding tube, locking gland, threaded gland, O-shaped steel, post, limit sleeve and protective cover.

2) characteristics;

It has the characteristics of locking the sliding tube and ensuring the separation of the two parts of the sealing performance, so when the sliding tube is loosened, it can ensure reliable sealing; when the sliding tube is locked, it can stay in any position. It not only brings convenience to use, but also strengthens the sealing performance, and has the characteristics of compact structure, small size and good seismic performance.

4. Measurement principle and operation method

1. Measurement principle

The level gauge detects the gas and liquid conversion surface through the up and down movement of the sliding pipe, on which the gas ejected from the valve outlet is converted into liquid, and the level gauge detects the liquid level in the storage tank through the relative height of the sliding pipe movement and the benchmark.

2. Method of operation

1) The protective cover of the level gauge is an important part to protect the internal parts of the level gauge. When the gas leaks due to damage to the seal, it can also prevent these gases from escaping. Therefore, when not in use, it should be properly tightened. If it is started, there may be gas leakage, so it should be loosened slowly.

2) When detecting the liquid level, use a wrench to loosen the locking gland before moving the sliding tube. According to the detected liquid level position, tighten the locking gland to fix the sliding tube. After measurement, loosen the locking gland, pull back the sliding tube, and tighten the locking gland.

3) Loosen the valve flap. If the sliding tube is immersed in liquid, the liquid will be ejected from the outlet of the valve body along the inner wall of the sliding tube by storing the internal pressure. Move the sliding tube according to the actual situation and measure the gas conversion surface of the discharged liquid. When the internal pressure of the storage tank is low or the sliding tube is pulled out too long, even if the liquid is converted into a layer of gas at the end of the sliding tube, there will be certain deviation. Therefore, if the above mentioned conversion point is found, the sliding tube must be slowly moved up and down two or three times during measurement to make the liquid level reading the same (the sliding tube pull-out height is equal). The distance from the bottom of the storage tank to the end of the sliding pipe is the liquid level, which can be measured by the height of the sliding pipe pulled out higher than the top end surface of the benchmark, and the filling volume can be found out through the V---H diagram.

5. Precautions

1) When using, when you want to loosen the locking gland, people should not face the top of the sliding tube to avoid hurting people.

2) When starting the valve flap, it is necessary to rotate one or two buttons to spray liquid or gas. Do not unscrew the valve flap or even lose it, causing a large amount of liquid leakage.

3) When using, people should not face the valve outlet to avoid hurting people when the medium is sprayed.

4) When moving the sliding tube up and down, the lower part of the sliding tube should be held as much as possible, and the sliding tube is not allowed to bend and collide.

4. Rotary tube level gauge

This kind of level gauge is mainly composed of rotating tube, dial, pointer, valve core and so on. The liquid level display principle of the rotary tube type liquid level gauge is exactly the same as that of the liquid level gauge. It is to determine the liquid level position by jetting out the gas phase or liquid phase medium through the small holes in the curved rotating tube. The difference is that the tube rotates instead of sliding up and down, so that the specific size and height of the liquid level can be indicated by the meter dial, and it can be installed in the middle of the head of the tank or on the cylinder for convenient observation.

The rotary tube level gauge has the advantages of accurate, intuitive and firm structure as the slide tube level gauge, and also has the disadvantages of ejection time error when the medium needs to be ejected and the action is too fast. Several domestic manufacturers have adopted this rotary tube level gauge for automotive tankers.

V. Float (Ball) Magnetic Type Level Gauge

The working principle of this level gauge is to use the buoyancy of the liquid to the float (ball). When the level gauge in the tank changes, the float (ball) also moves up and down. The float (ball) is used as a sensing element, which drives a pair of permanent magnets to rotate through a mechanical transmission mechanism. Another pair of magnets or pointers made of magnetized materials are installed outside the tank corresponding to the magnets. The inner and outer magnets are separated by blind plates made of non-magnetic materials such as stainless steel. When the inner magnet rotates due to the movement of the float, it also attracts the outer magnet (or magnetic pointer) to rotate, the pointer can then indicate the position of the liquid surface on the dial.

The magnetic level gauge is made of the principle that the magnetic lines of force penetrate the stainless steel blind plate and the liquid level is indicated by the pointer dial outside the tank body. It has the advantages of sealing, safety, reliability and intuitive indication. However, the structure is complex and the improvement of accuracy is limited.

6. Calculation method of tanker filling quantity

1. First confirm the filling quantity of the tank car

1) The filling capacity of the liquefied gas tanker is calculated as 0.42v,

2) Refined propylene tank car filling amount is calculated as 0.43v,

2. Find out the pull-out height or liquid level height of the sliding tube liquefaction meter on the v-h curve according to the filling volume.

3. The calculation of the filling amount of the above-mentioned tank car is generally only used as a control method for the filling amount of the tank car, and the actual filling weight must be checked by electronic weighing.