JPS594280Y2 - Dissolved oxygen measuring device - Google Patents

Description

[Detailed description of the invention] This invention relates to a dissolved oxygen measuring device, and in particular, it makes it easy to insert and remove the dissolved oxygen measuring sensor attached to the flow rate adding mechanism, and makes maintenance and inspection easy. It is an object of the present invention to provide a dissolved oxygen measuring device that performs a self-cleaning function and further facilitates maintenance of the sensor.

Generally used dissolved oxygen measurement sensors are constructed by having a diaphragm attached to one end of a container, sealing an electrolyte in the container with this diaphragm, and a pair of electrodes provided within the electrolyte. By bringing the sample water into contact with the sample water, oxygen dissolved in the sample water enters the electrolytic solution through the diaphragm, and a current flows between the electrodes according to the amount of penetration, and the amount of dissolved oxygen in the sample solution is determined by the amount of current. It is said to be a structure that allows you to know.

Such a diaphragm type sensor has the disadvantage that if there is no flow in the sample water in contact with the diaphragm surface, an oxygen diffusion gradient will occur in the sample water near the diaphragm, making it impossible to maintain correct measurement conditions at all times.

Such a situation is encountered, for example, when measuring dissolved oxygen in settling basins in sewage treatment plants.

For this reason, measurement devices have conventionally been proposed in which a water flow is created by a pump and a diaphragm of a dissolved oxygen measurement sensor is brought into contact with the water flow.

Figure 1 is a diagram of Utility Application No. 52-156613 (
This figure shows a dissolved oxygen measuring device equipped with a flow velocity adding mechanism proposed in Japanese Utility Model Application Publication No. 54-82698.

In FIG. 1, numeral 1 indicates a flow velocity adding mechanism. This flow rate adding mechanism 1 is composed of a pump 2 and a suction pipe 3 connected to the suction port of this pump 2, and creates a water flow in the suction pipe 3 by sucking and discharging sample water 4 by the pump 2. This is what I did.

A dissolved oxygen measuring sensor 5 is attached to this flow rate adding mechanism 1.

This sensor 5 is connected to the suction pipe 3 that constitutes the flow rate adding mechanism 1.
It is attached to a position below the water surface of the sample water 4, and its tip surface is in contact with the water flow flowing through the suction pipe 3 to measure the amount of oxygen dissolved in the sample water 4.

Note that 6 indicates a strainer attached to the tip of the suction pipe 3.

In reality, the sensor 5 is installed in a branch pipe that is connected at right angles to the suction pipe 3 that is vertically lowered from the water surface, and the sensor 5 can be removed from the flow rate adding mechanism 1 if necessary. There is.

The pinch sensor 5 needs to be periodically lifted out of the sample water for cleaning, zero point adjustment, span adjustment, etc.

However, in the previously proposed device, the branch pipe that supports the sensor 5 is installed in a direction perpendicular to the plate pipe 3, and the installation position is also adjusted to prevent air from being sucked through the lead wire extraction pipe 7. Since the sensor is located relatively deep, it is difficult to extract the sensor from the branch pipe or insert the sensor into the branch pipe.

Therefore, to take out the sensor 5, remove the suction pipe 3 from the pump 2, pull up the plate pipe 3 above the water surface, and remove the sensor 5.
I am trying to check.

Therefore, maintenance and inspection of the sensor 5 is troublesome.

Furthermore, the sample water 4 is often relatively dirty, which causes floating matter to adhere to the diaphragm surface of the sensor 5, causing measurement errors.

For this reason, there is also a drawback that the sensor 5 must be taken out and the diaphragm surface must be cleaned at relatively short intervals.

The first purpose of this invention is to make it easy to insert and remove the sensor.
It is an object of the present invention to provide a dissolved oxygen measuring device equipped with a flow velocity adding mechanism that allows easy maintenance and inspection of the sensor.

The second purpose of this invention is to provide a dissolved oxygen measurement device that can perform self-cleaning in the sensor part, thereby reducing the rate of dirt adhering to the diaphragm of the sensor and extending the period during which cleaning is required. There is something to do.

In this design, a branch pipe is installed in the sample water of the suction pipe that constitutes the flow rate addition mechanism, with the pipe axis facing the water surface of the sample water. By attaching it to the suction pipe, the open end surface of the branch pipe faces the water surface, which allows the dissolved oxygen measuring sensor to be inserted into and removed from the branch pipe even from above the water surface.

Furthermore, in this invention, an opening is formed below the water surface on the upper side depending on the sensor mounting position of the branch pipe, and the sample water is sucked through this opening toward the suction pipe.

Therefore, according to this invention, only the sensor can be inserted and removed from the branch pipe without raising the suction pipe above the water surface, and maintenance and inspection of the sensor can be easily performed. The sensor is cleaned with the sample water.

Therefore, the rate of dirt adhering to the sensor diaphragm is reduced,
Maintenance of the sensor can be further facilitated.

An embodiment of this invention will be described below in detail with reference to the drawings.

FIG. 2 shows an embodiment of this invention.

In FIG. 2, parts corresponding to those in FIG. It is connected so that it faces the water surface.

In this example, the suction pipe 3 is inserted vertically into the sample water 4, and the branch pipe 8 is connected to the suction pipe 3 so as to face diagonally upward at the position where the suction pipe 3 is immersed in the sample water 4. shows.

Furthermore, this example shows a case in which the branch pipe 8 is extended above the water surface so that the open end 8a of the branch pipe 8 approaches the land portion 10.

On the other hand, the branch pipe 8 is provided with means for supporting the sensor 5 in a predetermined position.

For example, as shown in an enlarged view in FIG.
1, the sensor 5 is formed with an enlarged portion 12, and this enlarged portion 12 engages with the protrusion 11, thereby holding the tip surface of the sensor 5, that is, the diaphragm surface, in a position where it is in contact with the water flow passing through the suction pipe 3. can do.

With this configuration, the sensor 5 can be connected from the land section 10.
By pulling up the signal extraction cable 13 attached to the sensor 5, the sensor 5 is guided to the branch pipe 8 and pulled up.
The sensor 5 can be easily taken out at the land section 10.

Therefore, maintenance and inspection of the sensor 5 can be easily performed.

In this invention, an opening 15 is further formed in the branch pipe 8.

This opening 15 is formed above the support portion of the sensor 5 and below the water surface.

By forming this opening 15, negative pressure is also generated in the branch pipe 8 when the pump 2 sucks up the sample water 4 through the suction pipe 3.
It flows into the plate-top pipe 3 through the supporting part.

Therefore, the sensor 5 is cleaned by the flowing sample water 4, and the rate at which dirt adheres to the diaphragm surface can be reduced.

Therefore, the inspection period can be lengthened, and maintenance of the sensor 5 becomes easier.

Moreover, by forming the opening 15, even if the attachment position of the branch pipe 8 to the suction pipe 3 is made shallow, air will not be sucked into the suction pipe 3 through the branch pipe 8.

Therefore, there is an advantage that the shorter the branch pipe 8, the easier the sensor 5 can be inserted and removed.

In other words, if the branch pipe 8 is connected to the suction pipe 3 at a shallow water depth without forming the opening 15, there is a risk that a large negative pressure will be generated in the branch pipe 8 and air will be sucked in.

If air is sucked into the suction pipe 3 in this way, there will be a drawback that the air will come into contact with the sensor 5 and cause a large error in the measured value.

Therefore, by forming the opening 15 in the branch pipe 8 as in this invention, even if the branch pipe 8 is connected at a shallow position, air will not be sucked in, and a dissolved oxygen measuring device that is easier to maintain can be provided.

If it is desired to further reduce the negative pressure generated in the branch pipe 8, the diameter of the portion of the suction pipe 3 to which the branch pipe 8 is connected may be increased as shown in FIG.

With this configuration, the connection position of the branch pipe 8 can be made even shallower.

Further, in the above description, the case where the branch pipe 8 is connected diagonally to the suction pipe 3 has been described, but as shown in FIG. The branch pipe 8 may be branched at right angles from the horizontal portion.

In this case, by tilting the branch pipe 8 toward the land section 10,
The upper end of the branch pipe 8 can be brought close to the land section 10, and the sensor 5 can be easily inserted and removed as in the case of FIG.

Further, in the above description, a case has been described in which the upper end of the branch pipe 8 is projected above the water surface, but this is not necessarily necessary, and the upper end of the branch pipe 8 may be located below the water surface as long as it is close to the land portion 10.

In this case, the upper end of the branch pipe 8 acts as the opening 15, and there is no particular need to form an opening on the side surface of the branch pipe 8.

As explained above, according to this invention, the dissolved oxygen measuring sensor 5 can be easily inserted and removed from the flow rate adding mechanism 1, and therefore, maintenance and inspection of the sensor 5 can be performed easily.

However, since the sample water is sucked in through the opening 15 formed in the branch pipe 8 to clean the sensor 5, the inspection period can be extended, and this effect is extremely large in practical use.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining the dissolved oxygen measuring device equipped with the flow rate addition mechanism proposed earlier, Fig. 2 is a cross-sectional view showing an embodiment of this invention, and Fig. 3 is the main part of this invention. FIGS. 4 and 5 are enlarged cross-sectional views showing one example, and FIGS. 4 and 5 are cross-sectional views showing other embodiments of this invention. 1: Flow rate addition mechanism, 2: Pump, 3: Suction pipe, 4:
Sample water, 5: sensor, 8: branch pipe, 9: tube axis of branch pipe 8, 1
5: Opening.

Claims (1)

[Scope of utility model registration request] A pump that takes in and discharges sample water, a branch pipe connected to the suction port of this pump with its axis intersecting the water surface of the sample water at a position in the sample water, and a A sensor is installed at a position where the tip surface is in contact with the water flow flowing through the suction pipe, and an opening is formed in the branch pipe above the installation position of the sensor and between the water surface. Oxygen measuring device.