JPH0420142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a concentration measuring device for a suspension such as sludge, and particularly to a concentration measuring device for measuring the concentration in a state where the liquid to be measured is pressurized to eliminate air bubbles contained in the liquid. Regarding.

When measuring suspensions containing air bubbles, such as sludge generated in sewage treatment processes, using an ultrasonic concentration meter, measurement errors due to the effects of air bubbles contained in the liquid to be treated are large. Various concentration measuring devices equipped with pressurized defoaming means have been proposed, and some of them have been put into practical use. has been done.

For example, in Japanese Utility Model Publication No. 56-28526, sludge as a liquid to be measured is stored in a closed tank, and compressed air is supplied into the closed tank to maintain the sludge in a pressurized state to eliminate air bubbles in the sludge. A concentration measuring device equipped with pressurized defoaming means is shown. However, such pressurized defoaming means requires a large number of valves and piping for supplying and discharging the liquid to be measured into a closed tank and for supplying and discharging compressed air, making the device not only complicated but also difficult to operate. I can't say it's easy. Furthermore, depending on the installation state of the device, a compressed air layer may be present in the ultrasonic path, resulting in measurement errors.

To solve the above-mentioned inconveniences, a pressurized defoaming chamber is provided into which the liquid to be measured flows in contact with the side wall of the liquid to be measured pipe connected to the main pipe of sludge, etc.
The liquid to be measured is automatically introduced into the pressurized defoaming chamber by using the movement of the sludge flowing in the pipe, that is, the dynamic pressure, and the valve body provided at the introduction opening is closed to allow the liquid to be measured to be introduced into the pressurized defoaming chamber. After the pressure defoaming chamber is sealed, the liquid to be measured in the pressure defoaming chamber is pressurized using compressed air or other pressurizing means, and the concentration is determined when the air bubbles contained in the liquid are extinguished by the pressurizing force. A concentration measuring device designed to measure
This is disclosed in Publication No. 43534, etc. However, in the case of the above device, it is difficult to say that the liquid to be measured is introduced into the pressurized defoaming chamber with certainty, especially when the piping is connected to a negative pressure line (the piping is installed in the suction side piping of the pump). (e.g.), there was an inconvenience that the liquid to be measured could not be introduced into the pressurized defoaming chamber.

In addition, in Japanese Utility Model Application Publication No. 57-86453, a pressurized defoaming chamber into which the liquid to be measured flows is provided in contact with the side wall of the liquid to be measured piping connected to the main pipe, similar to the above-mentioned device.
A diaphragm is disposed in the pressurized defoaming chamber, and the liquid to be measured is introduced into the pressurized defoaming chamber and sealed by a rotary gate valve provided at the introduction opening, and the liquid to be measured is pressurized by the diaphragm and contained in the liquid. A concentration measuring device is disclosed that includes a pressurized defoaming means that dissolves and eliminates air bubbles. However, this device has the disadvantage that the pressure applied by the diaphragm is weak and cannot eliminate air bubbles sufficiently.If large pressure is applied to the diaphragm to increase the pressure, the amount of elastic deformation of the diaphragm increases, resulting in a loss of restoring force. This has the disadvantage that it may drop and intervene in the ultrasonic path, causing measurement errors.

In view of the current situation, the present invention was made with the aim of eliminating the above-mentioned drawbacks, and it is extremely difficult to introduce and discharge the liquid to be measured into the pressurized defoaming chamber. The present invention provides a concentration measuring device equipped with a pressurized defoaming means that can realize reliable and highly accurate sampling measurements.

That is, the concentration measuring device of the present invention is a concentration measuring device equipped with a pressure defoaming means that measures the concentration in a state where the liquid to be measured is pressurized to dissolve and eliminate air bubbles contained in the liquid. The pressurized defoaming means is fitted with a cylinder that is connected in communication with an opening provided in a side wall of the liquid piping to be measured, and is fitted in the cylinder to face each other and is slidable independently of each other. It consists of two possible pistons and actuating means for both pistons, and when the two pistons approach and pressurize the liquid to be measured introduced between the two pistons through the opening, one piston acts as a gate valve. The cylinder is configured to seal the opening, and a transmitter and a receiver of an ultrasonic concentration meter are provided on the outer wall of the cylinder.

Embodiments of the present invention will be described below based on the drawings. Reference numeral 1 denotes a liquid pipe to be measured, which has an opening 2 on one side wall for sampling the liquid to be measured, and is connected to the main sludge pipe (not shown) through flange parts 3 connected on both sides. connected to.

A cylinder 4 forms a pressurized defoaming chamber, and is attached to the side wall of the pipe 1 via a communication opening 5 protruding from the side wall, and the communication opening 5 communicates with the opening 2. The cylinder 4 is sealed at both ends, and air supply and discharge ports 9 and 10 are provided in each end wall 7 and 8, respectively.

Reference numerals 11 and 12 denote a first piston and a second piston that are fitted into the cylinder 4 facing each other, both of which are formed into hollow bodies with open rear ends, and are capable of sliding independently of each other. When pressurized air is supplied to the hollow part 11a through the air supply/discharge port 9, the first piston moves forward by the pressurizing force, and sucks the air in the hollow part 11a through the air supply/discharge port 9 with a vacuum pump or the like. When it is ejected, it is configured to retreat using its suction force.

Similarly to the first piston 11, the second piston 12 is
The second piston 12 moves forward or backward by supplying pressurized air to the hollow part 12a through the air supply/discharge port 10 or by suctioning and discharging the air in the hollow part 12a through the air supply/discharge port 10. The side wall portion is configured to function as a gate valve that seals the communication opening 5.

Reference numerals 13 and 14 are a transmitter and a receiver of the ultrasonic densitometer, which are attached to the outer wall of the cylinder 4 so as to face each other in the diametrical direction. In the figure, reference numeral 6 denotes a gate valve disposed between the opening 2 and the communication opening 5. The gate valve 6 is normally open and is closed only in an emergency such as maintenance of the concentration measuring device.
Reference numeral 15 is a stop step portion that limits the forward position of the second piston 12.

Next, the operation of the concentration measuring device of the present invention having the above configuration will be explained.

Figure 1 shows a first piston 11 and a second piston 12.
are close to each other, indicating a state in which there is no liquid to be measured in the cylinder 4. In this state, the hollow part 11a of the first piston 11 and the cylinder 4 above it
When the air inside is suctioned and discharged by a vacuum pump (not shown) connected to the air supply/discharge port 9, the first piston 11 moves back as shown in FIG. 2 due to the suction force, and both pistons 11 and 12 are separated. A negative pressure chamber 16 is formed therebetween, and the liquid to be measured flowing in the pipe 1 is sucked into the negative pressure chamber 16 through the opening 2 and the communication opening 5. Next, pressurized air is supplied from the air supply/discharge port 10 to the hollow portion 12a of the second piston 12, and the second piston 12 moves forward. As shown in FIG. 3, the second piston 12 moves forward until it comes into contact with the stop step 15, and its side wall surface seals the communication opening 5, thereby blocking the connection between the cylinder 4 and the pipe 1. As a result, the liquid to be measured introduced into the cylinder 4 is sealed in a sealed pressurized defoaming chamber 17 formed between both pistons 11 and 12. Subsequently, pressurized air is supplied from the air supply/discharge port 9 to the hollow part 11a of the first piston 11, and the first piston 11 moves forward with the pressurizing force.
While approaching the second piston 12, the liquid to be measured is gradually pressurized, and the transmitter 13 emits ultrasonic waves under the condition that the pressurized force dissolves and eliminates the bubbles contained in the liquid, The concentration of the liquid to be measured is measured based on the degree of attenuation of the ultrasonic waves received by the receiver 14. After the concentration measurement is completed, the pressurized air that has been supplied to the hollow part 12a of the second piston 12 is discharged from the air supply/discharge port 10, and the pressurized air is further supplied to the hollow part 11a of the first piston 11. 2 piston 12 retreats and connects the communication opening 5 and cylinder 4.
The inside is in communication state, and both pistons 11 and 12
approaches, the liquid to be measured sealed in the pressurized defoaming chamber 17 is forcibly discharged into the piping 1 through the communication opening 5 and the opening 3, and finally both pistons 11 and 12 as shown in FIG. comes into contact with each other and there is no liquid to be measured in the cylinder 4.

The above pressurized defoaming and concentration measurement operations are repeated at predetermined intervals, and the data obtained is used for monitoring and controlling the sludge treatment process.

FIG. 4 shows an example in which the first piston 11 is used as a piston for sucking in and discharging the liquid to be measured, and the second piston 12 is used as a pressurizing piston that also serves as a gate valve, and both pistons 11 and 12 are air cylinders, respectively. It is configured to be moved forward and backward within the cylinder 4 by means of devices 18 and 19. Moreover, the second piston 12 does not directly seal the communication opening 5 when moving forward, but as shown by the imaginary line,
The pressurized defoaming chamber 1 is sealed between both pistons 11 and 12 when the piston moves forward to the position passing through the communication opening.
7 is formed, and the second piston 12 has a communication opening 5.
be cut off from Therefore, since the liquid to be measured also flows into the cylinder 4 behind the second piston 12 through the conduction opening 5, an escape groove 20 (see FIG. 5) is provided on the inner circumferential wall surface of the cylinder 4.
It is designed so that there is no problem with the retreat of step 2.

FIG. 5 shows an example in which a diaphragm 21 is used in place of the first piston 11 in the embodiments of FIGS. 1 to 3. The diaphragm 21, like the first piston 11, performs suction, pressurization, and discharge functions.

As explained above, according to the present invention, the liquid to be measured can be introduced into and discharged from the cylinder very reliably, and highly accurate sampling measurement can be realized. In particular, it has the advantage that the liquid to be measured can be reliably introduced into the cylinder even when the piping is arranged in a negative pressure line. In addition, the gate valve can be omitted, and the device is robust and has few failures, which has excellent practical effects.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a longitudinal sectional front view of the concentration measuring device according to the invention, FIGS. 2 and 3 are longitudinal sectional front views of main parts showing the same operating state, and FIG.
The figure is a longitudinal sectional front view showing another embodiment, and FIG.
A sectional view taken along the line 5-5' in the figure, and FIG. 6 is a longitudinal sectional front view of yet another embodiment. 1... Measured liquid piping, 2... Opening, 4... Cylinder, 5... Communication opening, 6... Gate valve,
9, 10... Air supply/discharge port, 11... First piston, 12... Second piston, 13, 14... Transmitter and receiver of ultrasonic concentration meter, 16... Negative pressure chamber, 17... ...Pressurized defoaming chamber.

Claims (1)

[Scope of Claims] 1. A concentration measuring device equipped with a pressure defoaming means that measures the concentration in a state where the liquid to be measured is pressurized to dissolve and eliminate air bubbles contained in the liquid, comprising: The pressurized defoaming means includes: a cylinder that is connected in communication with an opening provided in a side wall of the liquid pipe to be measured; and two cylinders that are fitted oppositely into the cylinder and that are slidable independently of each other. one piston, and actuating means for the two pistons, and when the two pistons approach and pressurize the liquid to be measured introduced between the two pistons through the opening, one of the pistons acts as a gate valve through the opening. 2. A suspension concentration measuring device, wherein a transmitter and a receiver of an ultrasonic concentration meter are provided on the outer wall of the cylinder. 2. The suspension concentration measuring device according to claim 1, wherein one of the two pistons is a suction/discharge piston, and the other is a pressurizing piston that also serves as a gate valve. 3. The suspension concentration measuring device according to claim 1 or 2, wherein a diaphragm is provided in place of the piston, which does not function as a gate valve.