JPH1157687A - Method and apparatus for injecting liquid chemical - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for injecting liquid chemical to cleaned water or sewage treatment water and the like capable of using even water rich in hardness components as pressurized water without the need for a water softener. SOLUTION: The apparatus 100 for injecting liquid chemical includes an injector 1, a pressurized water-conveying system 2 for conveying pressurized water to a pressurized water-introducing part 1a, a sodium hypoclorite-feeding system 3 for feeding sodium hypoclorite to a liquid chemical-introducing part 1b of the injector 1, and air-sucking system 4 through which the sodium hypoclorite-feeding system 3 sucks in air, The pressurized water allows the inside of the injector 1 to be at negative pressure, by which sodium hypoclorite is sucked into inside the injector 1, and air is also sucked from the air-sucking system 4. Within the injector 1, the sodium hypoclorite including air bubbles is diluted to be dilute solution including air bubbles by the pressurized water and ejected from an ejecting part 1c to be injected to a clean water basin J (or a drain pond and the like) through transport pipes 5. Thereby not requiring a water softener allows equipment and maintenance management costs to be reduced and economically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chemical injection method and a liquid chemical injection device, and more particularly, to a method for purifying water which can be used as pressurized water even with water containing a large amount of hardness without requiring a water softening device. The present invention relates to a method and an apparatus for injecting a liquid chemical into sewage treatment water or the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional example of a liquid chemical injection device for purifying water (or sewage treatment water or the like). The liquid chemical injection device 500 includes an injector 1, a pressurized water supply system 52 for supplying pressurized water to a pressurized water introduction unit 1 a of the injector 1, and a liquid chemical introduction unit 1 b of the injector 1.
And a sodium hypochlorite supply system 3 for supplying sodium hypochlorite (NaClO). The pressurized water supply system 52
Includes a water softening device S for softening the carrier water containing a large amount of the hardness component, a pump PA for pressurizing the softened carrier water to 100 to 300 kPa and sending it as pressurized water, and a pressure gauge PI. The sodium hypochlorite supply system 3 includes a sodium hypochlorite storage layer D, a pump PB, a sodium hypochlorite small discharge tank K, an electromagnetic flow meter R, an inflow control valve B,
And a pressure gauge PI. The sodium hypochlorite is diluted with pressurized water in the injector 1 to become a dilute solution, spouts from the spout 1c, and is injected into the clean water reservoir J (or a drainage reservoir, etc.) via the soft vinyl chloride transfer pipe 5. Is done.

[0003]

In the above-mentioned conventional liquid chemical injection device 500, if the hardness component (such as calcium ions and magnesium ions) of the carrier water is 20 mg / liter or less, the water softening device S is unnecessary. . However, if the hardness component of the carrier water exceeds 20 mg / liter (in the area of limestone geology, the hardness component of the carrier water is 50 to 1).
50 mg / liter), and a water softener S is required. The reason is that if hard water is used as pressurized water without being softened, scale such as calcium carbonate or magnesium carbonate adheres to the ejection portion 1c of the injector 1 and the transport pipe 5, the transport resistance increases, and the injector 1 does not function. Because. However, the provision of the water softener S increases equipment costs and maintenance costs, and is not economical. Therefore, an object of the present invention is to provide a liquid chemical injection method and a liquid chemical injection apparatus that can use water containing a large amount of hardness components as pressurized water without requiring a water softening device.

[0004]

According to a first aspect of the present invention, a pressurized water is supplied to a pressurized water introduction section of an injector, a liquid chemical is supplied to a liquid chemical introduction section of the injector, and the pressurized water mixed in the injector is provided. In a liquid chemical injection method of injecting a mixed liquid of liquid and liquid chemicals from an ejection portion of an injector and injecting the same into purified water or sewage treatment water, at least one of the pressurized water or the liquid chemicals is mixed with air to supply or supply water to the injector. A method for injecting a liquid chemical is provided. In the liquid medicine injection method according to the first aspect,
Since air is mixed with at least one of pressurized water and liquid chemicals to send or supply water to the injector, the gas phase acts to protect the channel walls in the injector and in the subsequent channels, and scale adheres to the channel walls It becomes difficult to do. In addition, the mixing action of the gas phase and the liquid phase exerts a cleaning action on the flow path wall, and detaches the scale from the flow path wall. Therefore, even without a water softening device, water containing a large amount of hardness components can be used as pressurized water.

[0005] In a second aspect, the present invention provides a method for supplying pressurized water to a pressurized water introduction section of an injector, supplying sodium hypochlorite to a liquid chemical introduction section of the injector, and diluting the hypochlorite with the pressurized water in the injector. In a liquid chemical injection method in which a diluted solution of acid soda is ejected from an ejection portion of an injector and injected into purified water or sewage treatment water, etc., air is mixed with at least one of the pressurized water and the sodium hypochlorite and sent to the injector. Alternatively, there is provided a liquid medicine injection method characterized by supplying. According to the quality standards of chemicals used by the Japan Water Works Association, the amount of caustic soda added to sodium hypochlorite is 2% or less in order to prevent a decrease in the effective chlorine concentration due to natural decomposition or photochemical decomposition. Usually, 0.4% caustic soda is added. When hard water is used as pressurized water without softening, calcium ions and magnesium ions in the hard water react with caustic soda to produce calcium carbonate and magnesium carbonate, which adhere to the ejector and transport pipe of the injector as scale. And
The transport resistance increases and the injector fails. However, in the liquid chemical injection method according to the second aspect, since air is mixed with at least one of pressurized water and sodium hypochlorite to feed or supply water to the injector, a gas phase is formed in the injector and in the subsequent flow path. It works so as to protect the flow path wall, and the scale is less likely to adhere to the flow path wall. In addition, the mixing action of the gas phase and the liquid phase exerts a cleaning action on the flow path wall, and detaches the scale from the flow path wall. Therefore, even without a water softening device, water containing a large amount of hardness components can be used as pressurized water.

In a third aspect, the present invention relates to an injector, a pressurized liquid supply system for supplying a pressurized liquid to a pressurized liquid introduction section of the injector, and a liquid chemical supply section for the liquid chemical introduction section of the injector. A liquid chemical supply system that supplies pressurized water and a liquid chemical in the injector, and ejects the mixture from the ejection section of the injector, and is connected to a pipe of the liquid chemical supply system. Provided is a liquid chemical injection device including an air suction system including an air suction pipe and an air suction amount control valve provided in the air suction pipe. By using the liquid medicine injection device according to the third aspect, the liquid medicine injection method according to the first aspect or the second aspect can be suitably implemented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this.

FIG. 1 is a configuration diagram showing an apparatus for injecting a liquid chemical into purified water (or sewage treatment water or the like) according to an embodiment of the present invention. The liquid chemical injection device 100 includes an injector 1, a pressurized water supply system 2 for supplying pressurized water to a pressurized water introduction unit 1 a of the injector 1, and a sodium hypochlorite supply device for supplying sodium hypochlorite to a liquid chemical introduction unit 1 b of the injector 1. The sodium chlorite supply system 3 has an air suction system 4 for sucking air. The pressurized water supply system 2 includes a pump PA for pressurizing the carrier water to 100 to 300 kPa and supplying the pressurized water, and a pressure gauge PI. It does not include a water softening device that softens the carrier water containing a large amount of hardness components. The sodium hypochlorite supply system 3 includes a sodium hypochlorite storage layer D, a pump PB, a sodium hypochlorite small discharge tank K, an electromagnetic flow meter R, an inflow control valve B, PI. As shown in FIG. 2, the air suction system 4 includes an air suction pipe 4 having one end (not shown) connected to a pipe of the sodium hypochlorite supply system 3.
1 and an air suction amount adjusting valve 42 provided at the other end of the air suction pipe 41. The air suction amount control valve 42
Is composed of an air suction amount adjusting block 42a, an air suction amount adjusting screw 42b, and a fixing nut 42c.

The pressure in the injector 1 is reduced to a negative pressure by the pressurized water, and sodium hypochlorite is sucked into the injector 1 by the negative pressure. At this time, air is also sucked from the air suction system 4 at the same time. Therefore, in the injector 1, the sodium hypochlorite containing air bubbles is diluted with pressurized water to become a diluting solution containing air bubbles, which is jetted from the jetting portion 1c, and passed through the soft vinyl chloride transfer pipe 5 to the water purifying tank J. (Or drainage ponds).

According to the liquid chemical injection device 100 described above,
Even without a water softening device, water containing a large amount of hardness components can be used as pressurized water. Therefore, equipment costs and maintenance management costs can be reduced, and the cost is reduced.

[Example] A total hardness of 51 mg / liter (calcium component 31 mg / liter, magnesium component 12
(mg / l, other components 8 mg / l) was fed at a feed pressure of 100 kPa and a feed rate of 150 l / min, and the inside of the injector 1 was set to a negative pressure of -1 to -2 kPa. An aqueous solution of sodium hypochlorite having an effective chlorine concentration of 11.82%, a sodium carbonate concentration of 0.23%, a caustic soda concentration of 0.27%, a salt concentration of 2.61%, and other additive concentrations of 0.2% is supplied.
It was sucked into the injector 1. At the same time, air was sucked from the air suction system 4. After a lapse of six months, the pipes after the injector 1 were disassembled and examined. As a result, no scale was attached and there was no decrease in operation performance.

[Comparative Example] Under the same conditions as in the above embodiment, but operating without sucking air from the air suction system 4, the operation performance deteriorated in three weeks, and the valve (ball valve) in the piping was Opening and closing became impossible. When the piping after the injector 1 was disassembled and examined, the scale was 1.5 to
It adhered to a thickness of 2.0 mm.

[0013]

According to the liquid chemical injection method and the liquid chemical injection device of the present invention, even if a water softening device is not provided, water containing a large amount of a hardness component can be directly used as pressurized water. Therefore, equipment costs and maintenance management costs can be reduced, and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for injecting a liquid chemical into purified water (or sewage treatment water or the like) according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an air suction system.

FIG. 3 is a configuration diagram of an example of a conventional liquid chemical injection device for purifying water (or sewage treatment water or the like).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injector 1a Pressurized water introduction part 1b Liquid chemical introduction part 1c Spout part 2 Pressurized water supply system 3 Sodium hypochlorite supply system 4 Air suction system 100 Liquid chemical injection device

Claims (3)

[Claims] 1. A pressurized water is supplied to a pressurized water introduction section of an injector, a liquid medicine is supplied to a liquid medicine introduction section of the injector, and a mixed liquid of the pressurized water and the liquid medicine mixed in the injector is ejected from an ejection section of the injector. A liquid chemical injection method for injecting water into purified water or sewage treatment water, wherein air is mixed with at least one of the pressurized water and the liquid chemical, and the mixture is fed to or supplied to an injector. 2. A pressurized water is supplied to a pressurized water introduction section of the injector, sodium hypochlorite is supplied to a liquid chemical introduction section of the injector, and a dilute solution of sodium hypochlorite diluted with the pressurized water in the injector is supplied to the injector. In a liquid chemical injection method of injecting into a purified water or a sewage treatment water by ejecting from an ejection portion, air is mixed with at least one of the pressurized water or the sodium hypochlorite, and then water is supplied or supplied to an injector. Liquid chemical injection method. 3. An injector, a pressurized liquid supply system for supplying a pressurized liquid to a pressurized liquid introduction section of the injector, and a liquid chemical supply system for supplying a liquid chemical to a liquid chemical introduction section of the injector. In a liquid chemical injection device that mixes pressurized water and a liquid chemical in the injector and jets out from a jet part of the injector, an air suction pipe connected to a pipe of the liquid chemical supply system,
A liquid chemical injection device comprising an air suction system including an air suction amount control valve provided in the air suction pipe.