JP2000126752A - Device for injection of chemicals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to inject chemicals momentarily by keeping chemicals pressure in a discharge path constant without using such a special instrument as a check valve. SOLUTION: This device is constituted of an inlet port 2 provided with a suction valve in the suction line of a pump 1 for injection of chemicals A, and a first discharge port 5 provided with a discharge valve and the second discharge port 6 provided with a degassing valve, which are arranged in parallel each other, in the discharge line of the pump 1. The first discharge port 5 of the pump 1 is connected to a chemicals-supply system 8 through discharge path 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial application] Chemicals are injected at a predetermined flow rate into a liquid (generally, water) supply system used in water and sewage equipment and chemical plants, etc., and the liquid is adapted to the intended use. The present invention relates to such a liquid injector.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Utility Model Laid-Open Publication No. 7-17977, a suction port provided with a suction valve is provided upstream of a pump chamber, and a discharge port provided with a discharge valve is provided downstream.
The downstream side of the discharge port is branched to form a first discharge port, and a pump for injecting a chemical solution as a second discharge port provided with a gas release valve.The first discharge port of the pump has a back pressure valve at an intermediate portion. There is a structure that is connected to a liquid supply system through a provided discharge path.

[0003]

The above-mentioned conventional example requires a gas vent valve (if gas is mixed in the pump chamber, the pump action is reduced due to expansion of the gas and the like and the pump quantitativeness is impaired). And the discharge valve are arranged in series with the pump chamber, so to speak, and the first discharge port communicating with the liquid supply system is provided between the two, so that the first discharge port and the second discharge port provided with the vent valve are provided. Are arranged in direct communication.

[0004] For this reason, the liquid pressure by the supply pump constituting the liquid supply system is applied to the degassing valve via the discharge path, and not only the liquid is discharged through the degassing valve, but also,
Does not function as a liquid injector.

Therefore, a back pressure valve (check valve) is provided in the discharge path.
And the need for this back pressure valve is not economical. Further, a spring is often used for the back pressure valve. However, the spring is often affected by the chemical solution, which causes a problem.

The present invention, for example, focuses on the drawbacks of such a conventional example, and has been devised in order to provide a drug solution injection device having an unconventional structure.

[0007]

SUMMARY OF THE INVENTION A suction port provided with a suction valve is provided upstream of a pump chamber, and a first discharge port provided with a discharge valve and a second discharge port provided with a vent valve are provided downstream. Are provided in parallel with each other to form a pump for injecting a drug solution, and the first outlet of the pump for injecting a drug solution is connected to a liquid supply system via a discharge path.

[0008]

The gas is discharged to the outside through the second discharge port during the operation of the chemical liquid injection pump, while the chemical liquid is discharged to the first discharge port.
The liquid is sequentially injected into the chemical supply system through the discharge path. Even if the operation of the pump is stopped, the hydraulic pressure in the discharge path of the supply pump provided in the liquid supply system is kept constant by the presence of the discharge valve at the first discharge port (check valve action), and the operation of the pump is stopped. Is restarted, the injection of the chemical solution into the liquid supply system is performed instantaneously.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a chemical liquid injection device according to the present invention, wherein A is a chemical liquid injection pump, and pump A is a suction port provided with a suction valve on the upstream side of a pump chamber 1 defined by a diaphragm. The suction port 2 is connected to a chemical solution tank 4 through a suction path 3.

A first discharge port 5 having a discharge valve and a second discharge port 6 having a degassing valve are provided in parallel on the downstream side of the pump chamber 1, and the first discharge port 5 is connected to the discharge path. While communicating with the liquid supply system 8 through 7, the second outlet 6 is communicated with the outside world.

The second outlet 6 is connected to the chemical tank 4
When a small amount of the chemical discharged together with the gas is returned to the chemical tank 4, wasteful consumption of the chemical can be prevented.

The liquid supply system 8 is provided with a supply pump 10, and supplies the liquid in the liquid tank 9 to the equipment by the supply pump 10.

FIG. 11 shows a third discharge port provided on the first discharge port 6 side of the liquid injection pump A.
Has a safety valve.

The pump A for injecting a chemical is not limited to a diaphragm type pump, but any reciprocating pump such as a plunger type pump is sufficient for implementing the present invention.

When the liquid injecting pump A is operated, that is, when the diaphragm defining the pump chamber 1 is reciprocated, the chemical in the chemical tank 4 is sucked by the suction path 3, the suction port 2, and the pump chamber 1. The liquid is supplied to the liquid supply system 8 through the first discharge port 5 and the discharge path 7 sequentially.

At this time, if gas is mixed in the pump chamber 1 due to gas volatilization and separation from the chemical solution by operation of the pump, the gas is discharged to the outside through the second discharge port 6.

Even if the operation of the pump A is temporarily stopped, the hydraulic pressure of the supply pump 10 on the liquid supply system 8 side becomes
The discharge valve of the first discharge port 5 is kept constant by the check valve function, and after the restart of the operation, the injection operation of the chemical solution is performed instantaneously.

[0018]

Since the present invention has the configuration as described above,
The fluid pressure in the discharge path can be kept constant, the chemical solution can be injected instantly with no time difference from the operation of the pump, and no special check valve is required on the discharge path. Therefore, an inexpensive device with a simple structure as a whole can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a drug solution injection device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump room 2 Suction port 5 First discharge port 6 Second discharge port 7 Discharge path 8 Liquid supply path

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H075 AA09 BB04 BB20 CC13 CC35 CC40 DA05 DA06 DA08 DA09 DA10 DA22 DB03 4G068 AA02 AB15 AC13 AD24 AD25 AE10 AF07

Claims (1)

[Claims] An inlet provided with a suction valve is provided upstream of a pump chamber, and a first outlet provided with a discharge valve and a second outlet provided with a vent valve are arranged in parallel with each other. A chemical solution injection pump, wherein the first outlet of the chemical solution injection pump is connected to a liquid supply system via a discharge path.