JPH0220075Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a PH adjustment device for water treatment equipment, and relates to a device that injects slaked lime milk dissolved at a certain concentration (10 to 20%), and is particularly useful. The present invention relates to a slaked lime milk injection device having a function of taking out only the necessary amount of slaked lime milk that is being circulated by a circulation pump using a positive displacement single screw type injection pump.

[Conventional technology]

It is proposed in the March 1976 issue of the Japan Water Works Association magazine, p. 30, that if lime milk with a concentration of 15 to 20% is used in a slaked lime injection device at a water treatment plant, scale will not build up inside the pipes. The purpose of injecting slaked lime milk is mainly for pH adjustment, and the injection rate is a small flow rate of about 0 to 20/min. Moreover, when the number of injection points is 4 to 8, the flow rate becomes even smaller. Traditionally, this type of device has been implemented by a combination of a flow meter and a control valve, or by a plunger type metering pump.

The diameter of the flow meter control valve is less than 10 mm, and because it is a slurry liquid (10% to 20% concentration), it is easily blocked.

Plunger-type metering pumps have a complicated internal structure and are easily clogged.

Both injection machines are affected by fluctuations in the primary pressure and become uncontrollable.

If the number of injection points increases due to the above points, the diameter of the injection machine becomes too small and there is no suitable injection machine. Therefore, the amount was increased by diluting with water, but in this case the concentration was less than 1%, and calcium carbonate scale was generated, causing blockage due to the scale.

[Problem that the invention attempts to solve]

The purpose of this invention is to provide a slaked lime milk injection device that can reliably control the injection of slaked lime milk at a small flow rate and high concentration without blockage.

[Means for solving problems]

This invention was developed in order to solve the problem that injection was not performed accurately due to blockage, which was conventionally controlled by a combination of a flow meter and a control valve, or a plunger type metering pump. Therefore, slaked lime milk with a concentration of 10% to 20% is circulated at a large flow rate (bore diameter of 50 mm or more, flow rate of 1 m/sec or more), and the required amount is pumped near the injection point using a volumetric type so as not to be affected by pressure fluctuations on the primary side. A single-screw type pump is used as the pump, and the pump is configured to be taken out.

〔Example〕

FIG. 1 shows a configuration diagram of one embodiment of the slaked lime milk injection device according to this invention.

Stirrer 2 in slaked lime milk storage tank 1, circulation pipe 3, circulation pump 4 attached to circulation pipe 3, positive displacement type 1
It is composed of a screw type injection pump 5 and a slaked lime dissolving device 6.

The operation is carried out by circulating the slaked lime milk (10 to 20% concentration) in the slaked lime milk storage tank 1 through the circulation pipe 3 using the circulation pump 4, and disposing a positive displacement single screw type injection pump 5 at each injection point. , inject only the required amount.
The slaked lime emulsion is transferred from the slaked lime dissolving device 6 and replenished. Positive displacement single screw infusion pumps are known as monopumps and are preferably of the type in which a threaded rotor rotates within a rubber stator.

As a result, the circulation pipe 3 has a large capacity (100/min
(above), so there is no fear of blockage and it is transported to the vicinity of the injection point. The infusion pump 5 is a positive displacement type 1
Since a shaft screw pump is used, it is not affected by pressure fluctuations on the primary side of the suction side, and since the characteristics of the pump are linear, it can be controlled by controlling only the rotation speed, eliminating the need for a flow meter or the like. Furthermore, since the distance to the injection point is short, there is no need to worry about blockages.

[Effect of idea]

This idea makes it possible to control the flow rate of slaked lime emulsion at a high concentration of 10 to 20%. It is possible to eliminate the conventional blockage and simplify the device.

[Brief explanation of drawings]

Figure 1 shows one of the slaked lime milk injection devices according to this invention.
A configuration diagram of an example is shown. 1... Slaked lime milk storage tank, 2... Stirrer, 3
...Circulation pipe, 4...Circulation pump, 5...Displacement type 1
Screw type injection pump, 6... slaked lime dissolving device.

Claims (1)

[Scope of utility model registration request] A slaked lime milk injection device that injects a milky lotion in which slaked lime is dissolved at a constant concentration, which includes a slaked lime milk storage tank, a circulation pipe that connects both ends to the slaked lime milk storage tank, a circulation pump attached to this circulation pipe, and the circulation pipe. A slaked lime milk injection device comprising a positive displacement single screw type injection pump attached to each injection point.