JPH0339734Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial field of application] This invention is a method for handling liquids that easily generate bubbles, such as sodium hypochlorite solution, which is used for sterilizing water in water supply and sewerage systems, using a diaphragm pump, etc. The system detects whether or not the liquid is actually flowing when the liquid is fed intermittently and with pulsation.

[Conventional technology]

Conventionally, electromagnetic flowmeters have been used as flowmeters as a practical method for detecting the flow of liquid in pipes, but they are expensive, are suitable for large volumes, and are not suitable for simplification due to the large size of the device. Worst of all, air adhered to the detection unit, causing misidentification.

In addition, some positive displacement flowmeters have a rotating top in the tapered tube section, but they have a narrow range of application to fluctuations in flow rate, and are inconvenient as they are not suitable for small volumes or pulsating flows.

It is unsuitable for detecting flows that involve injection of small volumes proportional to the amount of treated water, such as the delivery of sodium hypochlorite solution used for sterilization in water treatment such as water supply and sewage systems, but is not suitable for practical flow detection. There were no utensils.

[Problem that the invention attempts to solve]

A positive displacement pump such as a diaphragm pump is recommended for pumping a fixed amount of sodium hypochlorite solution, etc.
This liquid feeding is accompanied by pulsations because it is intermittently fed by the back-and-forth movement of the diaphragm and the check ball sealed in the pump inlet/outlet, so this invention has found a flow detector that fits this characteristic. It is something.

If air pockets occur in the pipe line due to damage to the pump suction side during liquid transfer or spontaneous bubble generation from the hypochlorite solution, the stagnant air may be removed even if the liquid is pumped. There was an inconvenience caused by the air obstruction, which caused a misunderstanding that the liquid was being fed even though the motor was only compressing it and not actually sending the liquid.

In addition, to prevent air from reaching the flow detection part, it is possible to take measures such as setting an air exhaust valve at the top of the float, which fluctuates depending on the liquid level, in the piping before the detection part. However, there were still problems in its adoption, as it required a lot of construction work, increased costs, and required a large installation space.

This invention eliminates these problems and promptly eliminates the air pockets generated on the inflow side of the flow detector, thereby ensuring reliable performance of the detector.

[Means to solve the problem]

This idea will be explained below based on the drawings.

A part of the pulsating solution flow path 13 containing bubbles is shielded by an upright transparent conduit 3 that can transmit light, and a constriction hole 4 is provided in the center of the conduit 14. Expanding tapered cavity 5 communicating with
A ceramic float 6 is installed in the detection channel 7 consisting of
is placed so as to close the aperture hole 4.

By drilling a short-circuit channel 8 having a loss resistance considerably smaller than the detection channel loss resistance including the weight resistance of the float 6 in parallel to the same pipe cross section shielding part 14 as this detection channel 7. Accordingly, the air 9 stagnant in the flow path below the float is preferentially discharged.

When the liquid supply capacity increases or the air pocket 9 becomes large, the short-circuit flow path 8 can be countered by increasing the diameter of the short-circuit flow path 8 or by drilling multiple short-circuit flow paths. I can do it.

Practically speaking, the short-circuit flow path inlet may be located near the inlet of the float detection section, and providing it above the inlet will improve the air venting effect.

The float 6 swings up and down in response to the stroke of the diaphragm when a pulsating solution is fed by a diaphragm pump.The floodlights are arranged facing each other slightly above the resting position of the float 6, spaced apart from the outer periphery of the transparent conduit. A photoelectric switch 12 consisting of a pair of a photodetector 10 and a photodetector 11 detects that the solution is actually flowing.

At this time, until the weight of the float, the loss resistance due to the detection channel, and the loss resistance due to the short circuit channel are balanced, the air in the air pocket 9 is preferentially removed to the short circuit channel 8, and the solution is also sent. The delivery amount is set within a range that does not affect the detected flow rate. At this time, the short-circuit channel is set so as to be out of the optical path of the photoelectric switch 12 for detection.

[Effect]

The solution taken out from the tank is pumped by the diaphragm pump 1, but due to the performance of the diaphragm pump, the solution is pulsated.
In addition, the solution is a sodium hypochlorite solution, and the solution is fed while generating oxygen bubbles during feeding, and passes through a flow detector.

At this time, an air pocket 9 is formed below the detection sensor due to the separation of air parcels from the middle of the pipe due to the weight of the float or throttle resistance, air mixing due to external factors, or due to the accumulation of air bubbles that gradually occur. .

In this state, if there is no short-circuit flow path 8 as shown in FIG. Therefore, the photoelectric switch 12 detects the vertical movement of the float 6 when only a small amount of air is sent, resulting in a misunderstanding that the flow of the solution is detected even though no solution is actually being sent.

Therefore, as shown in Figure 1, by providing the short-circuit flow path 8, there is resistance in the detection flow path due to the weight of the float, and the difference in resistance causes air to escape toward the short-circuit flow path. . If the air escapes and only liquid remains, the liquid will flow into the short-circuit channel until the resistance difference due to the weight of the float is balanced out, but if the capacity exceeds that, the float will float, and liquid will also flow into the detection channel, causing the upper and lower parts of the float to Movement is detected using a photoelectric switch.

If the float does not move up and down even once within one minute, an alarm will be issued. At this time, the short-circuit channel diameter, detection channel diameter, and weight of the float are designed in advance for the liquid sending capacity, so it can be used for liquid sending amounts that are greater than the minimum detectable liquid sending capacity. .

[Effect of idea]

This idea uses a minimal mechanism, is simple, and is low in cost. In order to remove the obstruction of accumulated air, a short-circuit flow path is provided so that air can escape preferentially through this flow path. (1) If there is an air pocket, it will escape through only the short circuit path.

(2) When it is a solution, it flows out from both the detection channel and the short circuit channel.

This is extremely convenient.

For fluctuations such as when the liquid delivery capacity increases,
Even if the float cannot withstand use due to large vertical movements, there is no need to replace the detector, and the same detector can be used by providing multiple short-circuit channels or increasing the diameter. , the width over which the liquid supply capacity can be detected becomes larger. In addition, by providing a short-circuit flow path, the width of the vertical movement of the ceramic float is reduced, which reduces wear on the float and the acrylic seat that receives the float, which lengthens the life of the float seat. Ta.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the flow detector of this invention and its system diagram, and Figure 2 is a sectional view taken along line A-A in Figure 1.
FIG. 3 shows a longitudinal cross-sectional view when no short-circuit flow path is provided. In the figure, 1...diaphragm pump, 2
...flow detector, 3...transparent pipe line, 4...throttle hole, 5...
Expanding taper cavity, 6... Float, 7... Detection channel, 8
...Short circuit flow path, 9...Air pocket, 10...Floodlight, 11
...light receiver, 12...photoelectric switch, 13...solution flow path, 14...shielding part.

Claims (1)

[Claims for Utility Model Registration] (1) In an upright transparent conduit through which light can pass through a part of the pulsating solution flow path containing bubbles, this conduit is shielded and a throttle hole is provided in the center of the conduit. A float is enclosed in a detection channel consisting of an expanding tapered cavity that communicates with this throttle hole in the downstream direction, and the float is placed so as to close the throttle hole, and the same conduit as the detection channel is installed. A short-circuit flow path having a loss resistance smaller than a detection flow path loss resistance including the weight resistance of the float is provided in parallel in the cross-sectional shielding part, and air stagnant in the flow path below the float is preferentially discharged. Accordingly, when feeding a pulsating liquid, the float swings up and down in response to the pulsation by a floodlight that is spaced apart from the outer periphery of the transparent conduit and placed oppositely slightly above the resting position of the float. A flow detector characterized by detecting by a photoelectric switch consisting of a pair of light receivers. (2) The flow detector according to claim 1, wherein the liquid containing air bubbles is a liquid that tends to generate air bubbles during liquid feeding, such as a sodium hypochlorite solution. (3) Utility model registration claim No. 1, characterized in that the pulsating liquid is caused by intermittent liquid feeding by a positive displacement pump such as a diaphragm pump. Flow detector according to item 1. (4) Claim 1 of the Utility Model Registration Claim characterized in that a plurality of short-circuit channels are formed so as to deviate from the optical path of a photoelectric switch in response to an increase in the flow rate of the liquid to be sent or an increase in the number of accumulated bubbles. flow detector.