JPH0134110Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a gas suction device capable of suctioning a fixed amount of gas from a number of locations.

Experimental wind tunnels are often used to simulate the diffusion of smoke emitted from factory chimneys in a laboratory. As shown in Fig. 1, a scaled model B of the chimney and surrounding topography is placed inside the wind tunnel body A, and tracer gas is discharged from this model B to observe its diffusion. That is, a sampling hole C is made on the surface of the model B inside the cylinder A, gas inside the cylinder A is sucked through the sampling hole C, and the degree of diffusion is estimated from the amount of tracer gas contained.

Normally, the number of sampling holes C drilled in the model B reaches several hundred, and each hole C simultaneously and
A fixed amount of gas must be inhaled. Conventionally, a gas suction device as shown in the figure was used.

1 is a metering pot, in which multiple tubes with the same diameter are lined up on the same level. Reference numeral 2 denotes a gas sampling tube, one end of which is connected to the upper end of the quantitative pot 1, and the other end connected to the sampling hole C via a sampling pot 2A in which tracer gas suction liquid is stored. A discharge pipe 4 is connected to a header 3 that communicates the lower ends of the metering pot 1 with each other, and a discharge pump 5 is interposed in the middle of the discharge pipe 4.

6 is a water storage tank that stores water W to be injected into the metering pot 1 and the header 3, and 7 is a pump that pumps up the water W in the water storage tank 6 to the head tank 8. Note that the head tank 8 and the discharge pipe 4 are connected through a pipe 9 having a valve 10.

11 is a wind speed sensor such as a hot wire that measures the wind speed inside the shell A, and its output is input to an anemometer 12. 13 is A/ which receives the output of the anemometer 12;
The capacity of the discharge pump 5 is adjusted by the D converter via the calculator 14 and the suction flow rate setting device 15.

Water is injected into metering pot 1 and header 3 using valve 1.
0 is opened, the pump 7 is driven, and the water in the water storage tank 6 is temporarily pumped up into the head tank 8 through the pipe 9. The valve 10 is closed when water is injected to the vicinity of the upper end of the metering pot 1. In addition, header 3 is U
The water level in each metering pot 1 is kept constant since it functions as a straight communication pipe.

Thereafter, the discharge pump 5 is driven to discharge a fixed amount of water from the metering pot 1 through the discharge pipe 4. As mentioned above, since the water level in the metering pot 1 is kept constant and the pipe diameters are the same, the flow rate of water discharged from each metering pot 1 should also be equal.

That is, Q: Discharge amount of discharge pump 5 N: Number of quantitative pots 1 q: Emission amount from each quantitative pot 1 given that, q=Q/N will be required.

Therefore, by arbitrarily determining the capacity Q of the discharge pump 5, it should be possible to set the amount of gas sucked into the gas sampling pipe 2 connected to each metering pot 1 to an arbitrary value.

However, the resistance in the piping portion leading to the header 3 changes randomly due to the accuracy of the metering pot 1, which should be manufactured uniformly, or due to dirt inside the metering pot 1 due to aging. For this reason, although the header 3 acts as a U-shaped communication pipe,
The water level in each metering pot 1 at the time when the discharge pump 5 is stopped varies. On the other hand, since each metering pot 1 is in communication with the header 3, each level tends to be the same after the discharge pump 5 stops, and some metering pots 1 perform suction while others supply gas from the sampling tube 2. This will cause the flow to flow backwards.

Therefore, not only the amount of gas sucked from each gas sampling tube 2 is not constant, but also a situation occurs in which the absorption liquid in the sampling pot 2A is discharged due to the backflow of gas, making it impossible to perform measurement.

The gas suction device of the present invention consists of a plurality of metering pots lined up at the same level, a gas sampling tube each having one end connected to the upper end of the specified amount pot and the other end opening to a desired gas suction device; A header that communicates the lower ends of the pot with the above-mentioned metering pot, a liquid injected into the header, an overflow pipe whose one end is connected to the header and whose other end is opened at a level near the lower end of the metering pot, and the overflow pipe. It consists of a valve installed in the gas sampling pipe, a discharge pipe connected to the header, and a discharge pump installed in the middle of the discharge pipe, so it is possible to aspirate the same amount of gas from all the gas sampling pipes. can do.

As described above, in the present invention, a discharge pipe via a discharge pump and an overflow pipe equipped with a valve are connected to the header to which the metering pot is connected.
Therefore, by closing the valve and driving the discharge pump, gas sampling can be performed in the same manner as with conventional devices. In addition, when the water level in the metering pot approaches the lower end, if you stop the discharge pump and open the overflow pipe valve, the water in each metering pot will be discharged by the water head pressure, and the water level will almost reach the opening level of the overflow pipe. descends. In other words, since the water is discharged without any movement between the metering pots, the problems of conventional devices are solved.

Hereinafter, the present invention will be described with reference to an embodiment of the apparatus shown in FIG. 2, but the structures and functions of the members denoted by the same reference numerals as in FIG. 1 are the same, so the explanation will be omitted.

16 is an overflow pipe, one end 16A is connected to the header 3, the other end 16B is expanded (a separate container may be connected) and is open to the atmosphere, and an overflow opening 16C is provided on the side of the pipe.
is provided. This opening 16C is located at a level near the lower end of the metering pot 1, at a level L indicated by a chain line in the figure. 17 is overflow pipe 1
This is a solenoid valve inserted in the middle of 6.

Reference numeral 18 denotes a level monitor, which includes a gauge tube 18A communicating with the header 3, a liquid level gauge 18B inserted into the gauge tube 18A, and a controller 18C receiving the output of the liquid level gauge 18B. The controller 18C is
It turns on and off the discharge pump 5 and the solenoid valve 17.

Now, in the apparatus of this embodiment as well, water W is injected into the metering pot 1 and the header 3 as before. In that case, the solenoid valve 17 is opened and closed as appropriate to inject water W up to the opening 16C of the overflow pipe 16. Note that the liquid level of the gauge tube 18A is the same as that of the metering pot 1.

The solenoid valve 17 is closed and the discharge pump 5 is driven to discharge the water W in the header 3 from the discharge pipe 4. Since each metering pot 1 and the gauge tube 18A are communicated with each other through the header 3, their respective water levels fall at approximately the same level, and gas is sucked from the sampling tube 2.

When the liquid level in the gauge tube 18A drops to L',
The liquid level in each metering pot 1 is near the level L'. When the level gauge 18B of the level monitor 18 detects the level L', the controller 18C stops the discharge pump 5 and opens the solenoid valve 17.

The liquid level in each metering pot 1 and the gauge tube 18A is such that water W is at the opening 16C of the overflow tube 16.
It descends as it is discharged from the opening 16C.
It stops at a level almost equal to the level L of (more precisely, a difference occurs between the internal pressure of the metering pot 1 and the atmospheric pressure).

Therefore, even if there is a slight difference in the liquid level in each metering pot, it will naturally fall to the level L, so that the water W between the metering pots 1 and 2, as in the conventional device, will not increase. No movement occurs. As a result, the amount of gas suctioned from the sampling tube 2 as the liquid level in each metering pot 1 falls becomes equal.
Furthermore, since there is no backflow of water W, there is no problem such as the gas absorption liquid in the sampling pot 2A being discharged.

[Brief explanation of drawings]

FIG. 1 is a diagram of a conventional device, and FIG. 2 is a diagram of a device showing an embodiment of the present invention. 1... Metering pot, 2... Gas sampling pipe, 3... Header, 4... Discharge pipe, 5... Discharge pump, 16... Overflow pipe, 17... Solenoid valve.

Claims (1)

[Scope of utility model registration request] A plurality of quantitative pots are lined up at the same level, and one end is connected to the upper end of each quantitative pot.
A gas sampling tube whose other end opens at a desired gas suction position, a header which communicates the lower ends of the metering pot with each other, a liquid injected into the metering pot and the header, and a tube whose one end is connected to the header, and a header whose other end is connected to the header. an overflow pipe whose end opens near the lower end of the metering pot, a valve interposed in the overflow pipe, and a discharge pipe connected to the header;
A gas suction device comprising a discharge pump interposed in the middle of the discharge pipe.