JP5506833B2 - Chemical supply device - Google Patents

Description

  The present invention relates to a chemical solution supply device, and more particularly, to a chemical solution supply device that includes a chemical solution storage tank that stores a chemical solution and is configured to supply chemicals in the chemical solution storage tank to a supply location.

  Conventionally, this kind of chemical solution supply device is used, for example, to supply a sodium hypochlorite aqueous solution as the chemical solution to a pipe for water supply through which clean water flows.

  The chemical supply apparatus is disposed in the chemical solution storage tank, a transfer pipe for supplying the chemical liquid in the chemical solution storage tank to a supply location, and the transfer pipe so that the chemical liquid can be transferred in the transfer pipe. And a pump.

  However, when the sodium hypochlorite aqueous solution is transferred to the water supply pipe using the chemical solution supply apparatus, the sodium hypochlorite aqueous solution is transferred in the transfer process in which the sodium hypochlorite aqueous solution is transferred through the transfer pipe. Since gas such as chlorine gas is generated as bubbles from the sodium hypochlorite aqueous solution, the bubbles adhere to the inner peripheral surface of the transfer pipe, and the bubbles gradually aggregate. When the aggregated bubbles (hereinafter, also referred to as “aggregated bubbles”) are transferred into the pump, a gas lock is generated in the pump, and the aqueous sodium hypochlorite solution is added to the clean water at a predetermined mass flow rate. It will not be possible to supply the pipes stably. If the sodium hypochlorite aqueous solution cannot be stably supplied to the water supply pipe at a predetermined mass flow rate, the sodium hypochlorite concentration in the water in the water supply pipe is not constant, and the quality of the water There may be cases where the criteria are not met.

  From this point of view, there is known a chemical liquid supply device provided with a mechanism for suppressing the supply of aggregated bubbles generated in the transfer process to the pump (for example, Patent Document 1).

JP 2003-80004 A

  By the way, using such a chemical supply device, after transferring the sodium hypochlorite aqueous solution to the water supply pipe, the pump is stopped for the purpose of maintenance of the water supply pipe and the sodium hypochlorite aqueous solution. Is stopped, and the pump is operated again to transfer the aqueous sodium hypochlorite solution to the water supply pipe.

However, since the sodium hypochlorite aqueous solution stays in the transfer pipe when the pump is stopped, bubbles attached to the inner peripheral surface of the transfer pipe are not caused to flow outside the transfer pipe due to water flow. Furthermore, new bubbles are generated from the sodium hypochlorite aqueous solution staying in the transfer pipe. Therefore, the longer the pump stop time, the more bubbles in the transfer pipe. In addition, when the pump is stopped, the pressure applied to the sodium hypochlorite aqueous solution in the transfer pipe becomes smaller than that during the operation of the pump, bubbles are likely to be generated, and the bubbles in the transfer pipe increase. When the bubbles in the transfer pipe increase, the aggregated bubbles generated in the transfer pipe also increase.
After the pump is stopped, when the pump is operated to transfer the sodium hypochlorite aqueous solution to the water supply pipe, the coagulated bubbles generated when the pump is stopped are transferred into the pump, and the gas lock is applied to the pump. Is likely to occur. As a result, there is a problem that the aqueous sodium hypochlorite solution cannot be stably supplied to the water supply pipe at a predetermined mass flow rate.
In addition, even if an attempt is made to transfer the sodium hypochlorite aqueous solution to the supply location while the transfer pipe is filled with the sodium hypochlorite aqueous solution, the amount of the coagulated bubbles generated in the transfer pipe when the pump is stopped is reduced. A location where no sodium chlorate aqueous solution exists is formed in the transfer pipe. Therefore, when the pump is operated after the pump is stopped and the aqueous sodium hypochlorite solution is transferred again to the water supply pipe, the aqueous sodium hypochlorite solution may not be transferred by the amount of the aggregated bubbles. . Therefore, there is also a problem that the sodium hypochlorite aqueous solution cannot be stably supplied to the water supply pipe at a predetermined mass flow rate.

  Such a problem may occur not only when the sodium hypochlorite aqueous solution is supplied to the water supply pipe, but also when a chemical solution that may generate bubbles is supplied to a supply location.

  In view of the above problems, the present invention provides a chemical solution supply that can stably supply a chemical solution to a supply location when the supply of the chemical solution to the supply location is stopped once and then supplied again to the supply location. It is an object to provide an apparatus.

The present invention provides a chemical solution storage tank for storing a chemical solution, a transfer pipe for supplying the chemical solution in the chemical solution storage tank to a supply location, and the transfer pipe so that the chemical solution can be transferred in the transfer pipe. A chemical solution supply device comprising a pump
A branch pipe branched from a position downstream of the pump of the transfer pipe is provided,
The transfer pipe includes a branch part provided with the branch pipe, a first transfer pipe upstream of the branch part, and a second transfer pipe downstream of the branch part,
The branch pipe is configured to return the chemical liquid from the branch portion to the chemical liquid storage tank,
The chemical liquid circulated in the first transfer pipe is configured to be transferred to either the second transfer pipe or the branch pipe as a transfer destination.
The chemical solution supply apparatus includes a switching device that can switch the transfer destination between the second transfer pipe and the branch pipe.

Such a chemical solution supply apparatus includes the branch pipe and the switching device, and thus can stop the supply of the chemical solution to the supply location without stopping the pump. Therefore, when the supply of the chemical liquid to the supply location is stopped, the aggregated bubbles are less likely to be generated in the first transfer pipe provided with the pump.
Therefore, such a chemical solution supply apparatus can stably supply the chemical solution to the supply location when the chemical solution is supplied again to the supply location after the supply of the chemical solution to the supply location is stopped once.

Also, the chemical liquid supply apparatus according to the present invention, prior Symbol switching device comprises provided with a back pressure valve disposed in the branch pipe, and a closing valve for opening and closing a flow path of the second transfer pipe.

In such a chemical liquid supply apparatus, since the switching device includes the back pressure valve and the on-off valve, the chemical liquid that has flowed through the first transfer pipe is branched by closing the on-off valve. Supplied only to piping. Further, by opening the on-off valve, the back pressure valve prevents the chemical liquid flowing through the first transfer pipe from flowing through the branch pipe, and the chemical liquid flowing through the first transfer pipe Is easily supplied to the second transfer pipe. Therefore, such a chemical supply device can be controlled so that the chemical flowing through the first transfer pipe is transferred to the second transfer pipe or the branch pipe by opening and closing the on-off valve.
Further, in the chemical solution supply device, in a state where the on-off valve is closed and the chemical solution is supplied to the branch pipe, the set pressure of the back pressure valve is added to the chemical solution upstream of the on-off valve. Equivalent pressure can be applied. Therefore, when the on-off valve is changed from the closed state to the open state by the pressure applied to the chemical on the upstream side of the on-off valve when the on-off valve is in the closed state, The chemical solution upstream of the valve is pumped to the downstream side of the on-off valve, so that the chemical solution can easily flow through the second transfer pipe.
Therefore, such a chemical solution supply device supplies the chemical solution to the supply location more stably when supplying the chemical solution to the supply location again after stopping the supply of the chemical solution to the supply location. There is an advantage that can be.
The back pressure valve prevents the flow of liquid when the pressure in the pipe upstream of the back pressure valve is equal to or lower than the set pressure, while the pressure in the pipe upstream of the back pressure valve When the pressure exceeds the set pressure, the valve circulates the liquid so as to keep the pressure in the pipe at the set pressure.

  As described above, the chemical solution supply apparatus of the present invention stably supplies the chemical solution to the supply location when supplying the chemical solution to the supply location again after stopping the supply of the chemical solution to the supply location. obtain.

1 is a schematic view of a chemical liquid supply apparatus according to an embodiment. 1 is a schematic view of a chemical liquid supply apparatus according to an embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the chemical solution supply apparatus 1 of the present embodiment includes a chemical solution storage tank 2 that stores a chemical solution, a transfer pipe 3 that supplies the chemical solution in the chemical solution storage tank 2 to a supply location A, and the chemical solution. A pump 4 arranged in the transfer pipe 3 and a branch pipe 5 branched from the downstream side of the pump 4 in the middle of the transfer pipe 3.

Although the said chemical | medical solution will not be specifically limited if it is a chemical | medical solution which can generate | occur | produce a bubble, As this chemical | medical solution, sodium hypochlorite aqueous solution etc. are mentioned, for example.
When a sodium hypochlorite aqueous solution is used as the chemical solution, the concentration of sodium hypochlorite in the sodium hypochlorite aqueous solution is preferably 0.1 mg / L to 1.5 mg / L, preferably 0.1 mg / L to 0.5 mg / L is more preferable.

  The supply location A is not particularly limited as long as it is a location where the chemical solution is desired to be supplied. Examples of the supply location include piping, tanks, and the like such as piping for drinking water through which clean water flows.

  The transfer pipe 3 includes a branch part 3c provided with the branch pipe 5, a first transfer pipe 3a upstream of the branch part 3c, and a second transfer pipe downstream of the branch part 3c. 3b. The first transfer pipe 3 a communicates with the chemical liquid storage tank 2 at the lower part of the chemical liquid storage tank 2. Further, the first transfer pipe 3a has a portion extending in the horizontal direction from the branch portion 3c. Further, the second transfer pipe 3b has a portion extending in the horizontal direction from the branch portion 3c.

  The said branch piping 5 is comprised so that the said chemical | medical solution may be returned to the said chemical | medical solution storage tank 2 from the said branch part 3c. The branch pipe 5 includes an upward extending portion 5a extending upward from the branch portion 3c. In the chemical liquid supply apparatus 1 according to the present embodiment, when the branch pipe 5 includes the upward extending portion 5a, the chemical liquid is transferred from the first transfer pipe 3a to the second transfer pipe 3b. The bubbles transferred together with the chemical solution are easily moved to the upward extending portion 5a by buoyancy, and there is an advantage that the bubbles in the transfer pipe 3 can be reduced.

  Further, the chemical liquid supply apparatus 1 of the present embodiment is configured such that the chemical liquid flowing through the first transfer pipe 3a is transferred to one of the second transfer pipe 3b and the branch pipe 5 as a transfer destination. ing.

  Further, the chemical solution supply apparatus 1 of the present embodiment includes a switching device 6 that can switch the transfer destination between the second transfer pipe 3b and the branch pipe 5.

  The switching device 6 opens and closes the flow path of the first back pressure valve 6a arranged in the branch pipe 5, the second back pressure valve 6b arranged in the second transfer pipe 3b, and the second transfer pipe 3b. And an on-off valve 6c. The second back pressure valve 6b is disposed on the downstream side of the on-off valve 6c. The set pressure of the first back pressure valve 6a is set higher than the set pressure of the second back pressure valve 6b. Since the set pressure of the first back pressure valve 6a is set to be higher than the set pressure of the second back pressure valve 6b, the chemical solution supply apparatus 1 of the present embodiment allows the pressure of the chemical solution applied to the second back pressure valve 6b. Can be kept constant, and there is an advantage that the chemical solution can be stably supplied to the supply location A. The on-off valve 6c is configured to be openable and closable.

The difference in the set pressure obtained by subtracting the set pressure of the second back pressure valve 6b from the set pressure of the first back pressure valve 6a is preferably 0.05 to 0.20 MPa, and more preferably 0.10 to 0.15 MPa. The chemical solution supply apparatus 1 of the present embodiment has an advantage that the chemical solution can be supplied to the supply location A more stably because the difference in the set pressure is 0.05 MPa or more.
The set pressure of the first back pressure valve 6a is preferably 0.30 to 0.40 MPa, and more preferably 0.30 to 0.35 MPa. When the set pressure of the first back pressure valve 6a is 0.30 MPa or more, the chemical solution supply apparatus 1 of the present embodiment is in a closed state (the supply of the chemical solution to the supply location A is performed). This has the advantage that the pressure in the pipe between the pump 4 and the on-off valve 6c can be kept constant when stopped).
The set pressure of the second back pressure valve 6b is preferably 0.15 to 0.25 MPa, and more preferably 0.15 to 0.20 MPa. When the set pressure of the second back pressure valve 6b is 0.15 MPa or more, the chemical liquid supply apparatus 1 according to the present embodiment is configured to supply the chemical liquid to the supply location A when the on-off valve 6c is in the open state (see FIG. At the time of implementation), the pressure in the pipe between the second back pressure valve 6b and the on-off valve 6c can be kept constant, and as a result, there is an advantage that the chemical solution can be stably supplied to the supply location A.

  In addition, although the chemical solution supply apparatus 1 of this embodiment has the said advantage by the said structure, the chemical solution supply apparatus of this invention is not limited to the said structure, A design change is possible suitably.

That is, in the chemical solution supply apparatus 1 of the present embodiment, the second transfer pipe 3b has a portion extending in the horizontal direction from the branch portion 3c. However, as shown in FIG. In the supply device 1, the second transfer pipe 3b may have a downward extending portion 3b1 extending downward from the branch portion 3c.
Such a chemical solution supply apparatus 1 has such a configuration, so that when the on-off valve is in a closed state, bubbles generated in the downward extending portion 3b1 move to the upward extending portion 5a by buoyancy. It becomes easy to be done. Therefore, when the on-off valve 6c is in the closed state, the chemical solution supply apparatus 1 reduces the bubbles generated in the downward extending portion 3b1, and the on-off valve 6c is in the open state from the closed state. The chemical solution is easily transferred smoothly through the second transfer pipe 3b.
Accordingly, the chemical solution supply apparatus 1 supplies the chemical solution to the supply location more stably when supplying the chemical solution to the supply location again after stopping the supply of the chemical solution to the supply location. There is an advantage that you can.

  Further, in the chemical liquid supply apparatus 1 of the present embodiment, the switching device 6 includes the first back pressure valve 6a, the second back pressure valve 6b, and the on-off valve 6c. The switching device 6 has a switching valve for switching the flow path of the chemical solution so that the chemical solution flowing through the first transfer piping 3a is transferred to the second transfer piping 3b or the branch piping 5. You may prepare for.

  1: Chemical solution supply device, 2: Chemical solution storage tank, 3: Transfer pipe, 3a: First transfer pipe, 3b: Second transfer pipe, 3b1: Downward extending part, 3c: Branch part, 4: Pump, 5: Branch Piping, 5a: upwardly extending portion, 6: switching device, 6a: first back pressure valve, 6b: second back pressure valve, 6c: on-off valve, A: location to be supplied

Claims (1)

A chemical solution storage tank for storing a chemical solution, a transfer pipe for supplying the chemical solution in the chemical solution storage tank to a supply location, and a pump disposed in the transfer pipe so that the chemical solution can be transferred in the transfer pipe; A chemical supply apparatus comprising:
A branch pipe branched from a position downstream of the pump of the transfer pipe is provided,
The transfer pipe includes a branch part provided with the branch pipe, a first transfer pipe upstream of the branch part, and a second transfer pipe downstream of the branch part,
The branch pipe is configured to return the chemical liquid from the branch portion to the chemical liquid storage tank,
The chemical liquid circulated in the first transfer pipe is configured to be transferred to either the second transfer pipe or the branch pipe as a transfer destination.
Ri Na and switching device is provided to enable switching the transfer destination forth between the second transfer pipe and the branch pipe,
Wherein the switching device, the branch and back-pressure valve arranged on the piping, chemical supply device according to claim Rukoto a and a closing valve for opening and closing a flow path of the second transfer pipe.

Images