JPS6350223B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas treatment device for 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 and kerosene into individual tank rooms at a loading base, and when they arrive at a gas station etc., 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 the remaining gas must be discharged. 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 density 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 device for a tank lorry 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 device for a tank lorry according to 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,
The gas pipe 4 has an on-off valve 11 that adjusts its flow rate.
The on-off valve 11 is provided with a control means 13 that instructs the on-off valve 11 to open/close or change the degree of opening of the valve based on a 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, in which each tank chamber 1 is provided with a bottom valve 2 for discharging liquid from its bottom, and a discharge pipe 3 is connected to each bottom valve. 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 blower 10 that sucks the gas remaining in the tank chamber 1 and an on-off valve 1 that adjusts the amount of gas flowing through the tank chamber 1 are provided between the
1 is interposed. Although the blower 10 may be omitted in some cases, the air supplied to the combustion chamber of the engine 6 is introduced not only from the air intake pipe 7 but also from the gas pipe 4. It is preferable to provide the above-mentioned blower 10 when the distance from the open end 4A to the connection portion 4B is longer than the connection 4B in the air intake pipe 7 and the ventilation resistance is large. This blower 10 is not limited to the suction type, but is provided with a pipe line (not shown) for supplying outside air to the tank chamber 1, and a push-type blower is interposed in the pipe line to push out the gas stagnant in the tank chamber to the gas pipe 4. You can do it like this. In the air intake pipe 7 downstream of the connection part 4B where the accumulated gas led out by the blower 10 joins, there is a gas sensor 12 for detecting the gas concentration in the air flowing therethrough.
is provided. 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%.
Based on the concentration signal from the gas sensor 12, a command is given to open/close the on-off valve 11 or change the valve opening degree. Although it is desirable that the opening/closing valve 11 be capable of arbitrarily changing the opening degree of the valve, it may be a simple on/off valve. The valve opening operation is performed by bending a bimetal with a heat coil whose heating degree is changed or by excitation of a solenoid in response to a command from the control means 13. In addition, 14 is an air filter provided in the gas air intake pipe 7 to purify the intake outside air;
Reference numeral 15 denotes a safety valve attached to the manhole hatch 16, which provides relief when the pressure inside the tank chamber 1 exceeds a set value, and sucks in outside air when the pressure within the tank chamber 1 exceeds a set value.

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 each tank chamber 1 shown in FIG. 2 is loaded with a predetermined liquid and transported to a gas station, the bottom valve 2 of each tank chamber 1 is sequentially opened by rotating the operating lever 17, as shown in the figure. 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. When the valve 11 is in the open state, the gas remaining in the tank chamber 1 is also sucked in through the gas pipe 4. As a result, the flammable gas is gradually burned in the engine 6, and the safety valve 1
5, outside air is introduced into the tank chamber 1, and the concentration of the retained gas is reduced. 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, the air intake pipe 7
There are more combustion components in the combustion chamber than when outside air is taken in only from outside air. Therefore, combustion starts before the compression stroke is completed, causing knocking, which adversely affects the engine 6. Therefore, the intake air concentration after the accumulated gases are mixed is detected by the gas sensor 12 provided in the air intake pipe 7, and this concentration signal is input to the control means 13.
In the above-mentioned notsking, the concentration of this intake air is, for example, 0.5.
If it were to occur at ~1.0%, to avoid it we would need to maintain the inspired air concentration below 0.5%. For this purpose, the control means 13 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, a signal is output that closes the on-off valve 11 or decreases the valve opening, and if it is lower, a signal is output that opens the on-off valve 11 or increases the valve opening. do. As a result, the concentration of intake air supplied to the engine 6 from the air intake pipe 7 is always maintained 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 has been diluted to below the explosive limit, or, if the truck has been traveling for a long time, has been 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, tank chamber 1 where gasoline gas remains
The risk of explosion is greatest when loading diesel or kerosene into the tank. 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.

[Effects of the Invention] As can be seen from the description of the above embodiments, the present invention has the following advantages:
The gas piping that discharges the flammable gas that accumulates in the tank room is connected to the air intake pipe, and the gas piping's on-off valve is controlled according to the concentration signal from the gas sensor. While the vehicle is running, the gas accumulated in the tank chamber can be combusted without adversely affecting engine operation. 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 room, 4...Gas piping, 4B...Connection part, 6...Engine, 7...Air supply piping,
11...Opening/closing 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, and an on-off valve is interposed in the gas pipe to adjust the amount of flow of the gas, and a control means is provided to the on-off valve to instruct the on-off valve to open/close or change the degree of opening of the valve based on the signal from the gas sensor. A gas treatment device for a tank truck, characterized by: