JPS6350224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to gas treatment in a tank lorry, and more particularly to a gas treatment device in which flammable gas remaining in a tank chamber is combusted by an engine. This is used in the technical field to prevent flammable gases from exploding due to the charging phenomenon that occurs when loading liquids.

[Prior art]

Tank trucks usually load liquids such as gasoline or kerosene into individual tank rooms at a loading base, and when they arrive at a gas station or the like, they unload the liquids into underground tanks. At that time, if gas evaporated from the liquid stored in this underground tank remains, unloading will not be carried out smoothly, so it is necessary to discharge the remaining gas. However, simply releasing this gas causes air pollution, so it is introduced into the unloading tank room or another empty tank room and transported to the loading terminal, where it is treated. At the gas processing facility at the base, the gas, which has a higher specific gravity than air, is led out of each bottom valve in the tank chamber, passed through activated carbon or incinerated in a combustion furnace, and then released into the atmosphere as a harmless gas.

By the way, discharging the gas evaporated from the flammable liquid from the tank chamber is necessary not only to eliminate the above-mentioned air pollution, but also to prevent the flammable gas from exploding due to the charging phenomenon that occurs during loading. It is said that That is, in a tank truck, regardless of the number of tank chambers, the type of liquid loaded into the tank chamber and the type of gas introduced for gas treatment often differ each time. Liquid loading at the loading base is carried out by inserting a loading arm into a manhole installed at the top of the tank room. Static electricity is generated accordingly. In particular, when loading light oil or kerosene, the amount of gas generated increases, and a phenomenon occurs in which a tank containing positive liquid becomes negatively charged. On the other hand, gas evaporated from gasoline is significantly more flammable than gas evaporated from diesel oil. When such a gas is introduced into the tank room from an underground tank at a gas station and remains in the tank room at a concentration of about 1 to 6%, the above-mentioned static electricity will cause the surface of the liquid to contact the tank wall. This is because if a spark occurs between the two, the accumulated gas will ignite and explode, resulting in an extremely dangerous situation.

The above-mentioned gas processing is carried out at a well-equipped loading base, so it cannot be done unless the tank truck returns to the base, and the processing requires 1Kl of gas.
It takes 2 to 3 minutes per turn, so a large tank truck with a tank capacity of over 10Kl requires a lot of time. As a result, even if the tank truck arrives at the loading base, loading cannot be started immediately, which poses a problem that improves the operating efficiency of the tank truck. In addition, each base will be required to install a designated gas processing facility, and will be required to have a complete support system for transporting flammable liquids.

[Purpose of the invention]

The present invention was made in view of the above-mentioned problems, and its purpose is to burn off flammable gas in the tank chamber while the tank truck is traveling until it reaches the loading station, thereby avoiding air pollution, and to avoid air pollution during loading. To provide a gas treatment treatment for a tank truck that can avoid explosion within the tank even if sparks are generated due to generated static electricity.

[Structure of the invention]

The feature of the gas treatment treatment in the tank lorry of the present invention is that, as shown in FIG. connected to the air intake pipe 7 downstream of the connection part 4B,
A gas sensor 12 for detecting gas concentration is installed,
A gas on-off valve 10 that adjusts the flow rate is interposed in the gas pipe 4, and an air on-off valve 11 that adjusts the flow rate is interposed upstream of the connection portion 4B of the air intake pipe 7, and both on-off valves 10 , 11 are provided with a control means 13 for instructing opening/closing or changing the valve opening degree based on the signal from the gas sensor 12.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to drawings of embodiments thereof. FIG. 1 is an overall system diagram showing one embodiment of the gas treatment device. Each tank chamber 1 is provided with a bottom valve 2 for discharging liquid from the bottom thereof, and a discharge pipe 3 is connected to the bottom valve 2. ing. Furthermore, a gas pipe 4 for discharging the flammable gas staying therein is inserted into each chamber, and its open end 4A extends to the vicinity of the bottom of the tank chamber in order to completely discharge the gas having a large specific gravity. This gas pipe 4 is unified after passing through a valve 5 provided outside each tank chamber 1 shown in FIG. 2, and the other end is connected to an air intake pipe 7 that supplies air to a diesel engine 6. There is. A manual valve 8 is provided in the inlet pipe 4a of the gas pipe 4, and a manual valve 9 is provided in the outlet pipe 4b.
A gas on-off valve 10 for adjusting the amount of flammable gas flowing through is interposed between the air intake pipe 7 and an air on-off valve 11 for adjusting the amount of air flowing through the air intake pipe 7 . Each of these on-off valves 10, 11
Connection part 4B where the gas and air that have passed through join together
A gas sensor 12 is provided in the air intake pipe 7 downstream of the air intake pipe 7 to detect the gas concentration in the air flowing therethrough. This gas sensor 12 mainly detects the concentration of hydrocarbons, and has a function of detecting the amount of flammable gas sucked from the tank chamber. This is to sequentially output the concentration signal to the control means 13 described below in order to prevent knocking in the engine 6 and to promote the discharge of flammable gas if the amount is small. The control means 13 is, for example, a microcomputer, and stores the gas concentration at which the engine 6 knocks, for example, 0.5 to 1.0%, and controls the opening and closing of the gas and air on-off valves 10 and 11 based on the concentration signal from the gas sensor 12. Or, it is designed to command a change in the valve opening. The valve opening operation is performed by bending a bimetal with a heat coil whose heating degree is changed in response to a command from the control means 13, or by excitation of a solenoid. In addition, 14 is an air filter installed in the air intake pipe 7 to purify the intake outside air, and 15 is a safety valve attached to the manhole hatch 16, which is relieved when the pressure inside the tank chamber 1 exceeds a set value, and the following In this case, outside air is inhaled.

According to the embodiment having such a configuration, the flammable gas remaining in the tank chamber 1 can be burned and removed while the vehicle is running by operating as follows.

When a predetermined liquid is loaded into each tank chamber 1 shown in FIG. 2 and transported to a gas station, the bottom valve 2 of each tank chamber 1 is sequentially opened by rotating the operating lever 17. unloaded into underground tanks, etc. At this time, flammable gas that has evaporated from the remaining liquid remains in the underground tank.
While introducing this into the tank chamber 1 from a hose (not shown) through the introduction pipe line 4a of the gas pipe 4, the liquid in the tank chamber 1 is discharged to the underground tank. At this time, the manual valve 8 of the inlet pipe 4a and the valve 5 of the tank chamber 1 into which the flammable gas is introduced are opened, while the manual valve 9 of the outlet pipe 4b is closed and the air intake pipe for the flammable gas is opened. 7 is prevented. When unloading is completed, the bottom valve 2 is closed and the tank chamber 1 is filled with flammable gas. The tank truck returns to the loading base with the manual valve 8 closed, but at that time,
The manual valve 9 is opened, and the flammable gas remaining in the tank chamber 1 is gradually combusted by the diesel engine 6. That is, the engine 6 takes in outside air through the air intake pipe 7, purifies it with the air filter 14, and then takes it into the combustion chamber by suction negative pressure during the intake stroke, but at this time, the gas on-off valve 10 is in the open state. Then, the gas remaining in the tank chamber 1 is also sucked into the gas pipe 4. As a result, the flammable gas is gradually burned in the engine 6, and outside air is introduced into the tank chamber 1 via the safety valve 15 to replenish the amount of flammable gas, thereby reducing the concentration of the retained gas. In addition, it is necessary to dilute the concentration of the accumulated gas to 1% or less in the case of gasoline gas and 6% or less in the case of diesel oil to avoid ignition due to static electricity sparks. . On the other hand, when the flammable accumulated gas is sucked into the engine 6 from the tank chamber 1 in this way, the amount of combustion components in the combustion chamber increases compared to when outside air is sucked only from the air intake pipe 7.
Therefore, combustion starts before the compression stroke is completed, causing knocking, which adversely affects the engine 6. Therefore, the gas sensor 1 installed in the air intake pipe 7 measures the intake air concentration after the accumulated gases have mixed.
2, and this concentration signal is detected by the control means 1.
3 is input. If the above-mentioned knocking occurs when the concentration of this intake air is, for example, 0.5 to 1.0%, then
To avoid this, it is necessary to maintain the intake air concentration below 0.5%. For this purpose, control means 1
3 receives the gas concentration signal and determines whether or not suction from the gas pipe 4 is necessary or not. That is, if the gas concentration is higher than the set value, the gas on-off valve 10
The air opening/closing valve 1 outputs a signal to close the valve or reduce the opening degree of the valve, and also to avoid a rise in intake negative pressure in the engine 6 and maintain the intake air amount.
A signal is output to increase the opening degree of the valve 1, and if it is low, a signal is output to the gas and air on-off valves 10 and 11 to perform the opposite operation. As a result, the concentration of intake air supplied from the air intake pipe 7 to the engine 6 is
Always kept below the set value. In this way, by the time the tank truck returns to the loading base, the concentration of flammable gas in the tank chamber 1 is reduced and knocking is prevented, and the flammable gas is burned by the engine 6 and pollutes the air. is reduced.

When the tank truck arrives at the loading station, the flammable gas in the tank chamber 1 is diluted to below the explosion limit, or if the traveling time is long, it is completely replaced with air. By the way, it is known that when the accumulated gas is gasoline, its flammability is the highest, while when the loaded liquid is light oil or kerosene, its electrostatic property is the highest. Therefore, the risk of explosion is highest when loading diesel oil or kerosene into the tank chamber 1 where gasoline gas is retained. However, even in such a case, static electricity is generated during loading with the loading arm, and even if the amount of charge increases and sparks occur, since the gas concentration of gasoline is below the specified concentration, What happens when it explodes is avoided.

Although the above embodiments have been explained using a diesel engine as an example, the present invention can also be applied to gasoline engines and other engines. Furthermore, it goes without saying that the present invention is applicable not only to tank trucks having three tank chambers but also to all cases having one or more tank chambers and handling one or more types of liquid.

〔Effect of the invention〕

As can be seen from the description of the embodiments above, the present invention has the following features:
The gas piping for discharging the flammable gas accumulated in the tank chamber is connected to the air intake pipe, and the gas on-off valve of the piping and the air on-off valve of the air intake pipe are controlled according to the concentration signal from the gas sensor. , without adversely affecting engine operation while the tank truck is traveling until it reaches the loading base.
The gas stagnant in the tank chamber can be combusted.
Therefore, air pollution due to the release of flammable gas can be avoided, and the tank truck can immediately load liquid without requiring time for gas processing at the loading base, thereby improving its operating efficiency. Of course, even if sparks are generated due to static electricity generated during loading, an explosion within the tank is avoided, ensuring safety during loading operations.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of a gas treatment device in a tank lorry according to the present invention, and FIG. 2 is an overall schematic diagram of a tank lorry equipped with the gas treatment device. 1...Tank chamber, 4...Gas piping, 4B...Connection part, 6...Engine, 7...Air intake pipe, 1
0... Gas on-off valve, 11... Air on-off valve, 12...
...Gas sensor, 13...Control means.

Claims (1)

[Claims] 1. A gas pipe that discharges flammable gas accumulated in a tank chamber is connected to an air intake pipe that supplies air to the engine, and the gas concentration is detected in the air intake pipe downstream of the connection point. a gas sensor is attached to the gas pipe, a gas on-off valve for adjusting the flow rate is interposed in the gas pipe, and an air on-off valve for adjusting the flow rate is interposed upstream of the connection portion of the air intake pipe; A gas processing treatment for a tank truck, characterized in that the on-off valve is provided with a control means for instructing the on-off valve to open/close or change the degree of opening of the valve based on the signal from the gas sensor.