The operating instruction of chemical dosing system

The chemical dosing system which manufactured by Peide Water Treatment Equipment Co.,Ltd with competitive price,simple operation and maintenance. The chemical dosing system is one of the core products of PEIDE.The package of chemical dosing system usually adopt wooden cases. The operating instruction of chemical dosing system, including structure declaration,use of chemical dosing system, maintenance of the chemical dosing system, breakdowns and solutions ,instruction of control cabinet.The details as below:

I. The overview of chemical dosing system:
In fields of electric power, petroleum, chemical industry, metallurgical industry, environmental engineering, water treatment, etc., a certain liquid is often needed to be injected into another kind of liquid to make a mixture, or to make the agent added react with a certain component existing in the liquid in order to meet expected process requirements.
This kind of chemical dosing system has a simple structure and is convenient to install. It mainly consists of metering chest (agent storage chest), metering pump (chemical dosing pump), control system, line-mounted valves and so on, which are commonly concentrated and mounted in a chemical dosing room. The device integrates metering chest, metering pump and control system, which means they are mounted on one base. The purchase, manufacture, assembling, debugging and trial operation of the equipment are completed by PEIDE. The only thing needed to be done by the user is connecting the exit of metering pump with chemical dosing pipeline and the entrance and exit of metering chest and inlet pipe etc. after putting combined chemical dosing unit in chemical dosing room, that is ready to put into operation.

II. The structure declaration of chemical dosing system:
1.The chemical dosing system is made of solution chest , blender(optional), metering pump, control cabinet,piping, antifluctuator, pressure gauge,Y type filter, level gauge, iquid level sensor(optional), conductivity(optional), on-line monitoring for PH(optional), on-line monitoring for corrosion(optional).
2.All the parts are installed on a rack,which formed to a separate dosing unit, greatly reduce the workload of chemical design and on-site installation and reduce the occupied area.
3.The solution chest is equipped with a board level gauge, which can realize local display and has low level shutdown function.
4.It can be realized on the manual dosing and automatic dosing adjustment. All the electrical appliances and instruments are assembly into the electric cabinet.The structure is compact, the debugging and operation not only safe,but also convenient.

III. The use of chemical dosing system:
1.Rotate the connector of on-line monitoring for PH, connect all the piping of chemical dosing system, check and fix each thread interface to avoid fluid leakage.
2.Connect the power supply of metering pump:
(1)Open the junction box of electric control cabinet and connect the power line which meets the need with corresponding terminal blocks.
3.Close the drain valve.
4.According to the concentration of the chemical to prepare, the volume of agent tank and the agent concentration, meter the amount of the agent and water, add the agent into the tank, turn on the water valve and add the water needed.
5.Solution preparation: pour a certain amount of agent (solid or liquid) into the solution chest, turn on water valve to inject water and stop when the liquid level reaches a predetermined level,then set the predetermined level of agent,to make the agent in solution chest uniformly mixed for chemical dosing use.
6.Chemical adding: turn on the valve of chemical dosing system, adjust the dose of metering pump to a certain value, turn on the metering pump, add the agent to the chemical dosing point and continuously adjust the dose of metering pump to enable the dose satisfy process requirements. If it can not satisfy the requirements, the concentration of the chemical needs to be prepared again. In the chemical dosing system, metering pumps which are in the form of positive displacement and are able to adjust the length of stroke.
7.The survivor of solution chest drain out from drain outlet. The liquid level of solution chest is according to the level gauge.

8.When the dosing liquid of the dosing tank is lower than the minimum level of liquids, the dosing pump stop working automatically.
9.When the PH of the dosing liquid of the dosing tank is higher or lower than a certain value,(the value refer to the attachment of PH meter instruction to set),the dosing pump stop working automatically.
10.When the conductivity is higher than the set value (the value refer to the attachment of conductivity instruction to set), the drain valve open to sewage until the conductivity is lower than the set value, stop working automatically.
11.On-line monitoring for corrosion(see the attachment of corrosion meter instruction)
12.Metering pump(see the attachment of metering pumpinstruction)
13.According to the clean degree of the agent,it should be regularly to clean the solution chest.

IV. The instruction of control cabinet:
4.1The instruction of manual control cabinet:
1.The power of the electric cabinet is three phase four wire system,50HZ
2.Keep dry in the control cabinet, and no corrosive gases and liquid are allowed to enter.
3.Switch each switch on “Turn off manually”, close the power switch of the cabinet.
4.When the power on,switch “metering pump” onto “automatically”,the device enters automatic operation state,and indicator lights are on.
5.If the working pump breakdown in the operation,it should be promptly cut off the power supply,close the relevant valves,start the standby pump and continue to dosing.
6.The control cabinet has a function of stop-pump protection in low liquid level:When the liquid level in the solution chest reaches the low liquid level,the dosing pump stops working automatically.
7.The drain valve:
7.1Automatic sewage:
switch “drain valve turn off manually/automatically/turn on manually”onto “automatically”,when the conductivity higher than the set value,10.the drain valve open to sewage until the conductivity is lower than the set value, stop working automatically.
The drain valve open to sewage,when the time reach the set value,it stop automatically.

7.2Manual sewage:
When the conductivity of the electric cabinet shows higher than the required value,manual switch”drain valve turn off manually/automatically/turn on manually” onto “turn on manually”,until the conductivity shows within the required value,manual switch”drain valve turn off manually/automatically/turn on manually” onto “turn off manually”,stop the draining.
8.On-line monitoring for PH:When the PHshows higher than the required value,the metering pump stop working.
4.2The instruction of control cabinet for chemical dosing system
The “turn off manually/automatically/turn on manually” switch is installed on the board of the control cabinet:when the switch onto “turn on automatically”,manual dosing can be done by ontology device.(The manual control methods refer to 4.1)

V. The maintenance of the chemical dosing system
1. Piping should be kept clear all the time, each join part, filter, feed port and discharge port of the device should be checked regularly and irregularly to see whether there are deposited materials in these parts. If there is any, it should be cleaned promptly.
2. Regularly check whether the inlet of metering pump is blocked, and regularly clean pipes and filters to prevent clogging.
3.The churn-dasher,to check if the stirring shaft flexible rotation,whether twisted impeller,shaft sleeve is loose,in order to avoid excessive shaft torque,mixing power consumption,if any,should be replaced in a timely manner.
4.Check the safety valve, the pressure gauge and all pipe valves to prevent leakage.

VI. The configuration of chemical dosing system:

One tank with One pump chemical dosing systemTwo tank with Two pump chemical dosing systemThree tank with Three pump chemical dosing systemFour tank with Four pump chemical dosing system






                                    One tank with one pump     Two tank with two pump    Three tank with three pump   Four tank with four pump


VII. The breakdowns and solutions of chemical dosing system

Breakdowns Reasons Methods of eliminating













The agent outlet

does not discharge

liquid or certified

capacity is not

enough (Note:

The instruction

for hydraulic

diaphragm pump).

The inlet pipes are blocked or the resistance is too big. Dredge inlet pipes and take

relevant measures to

reduce the resistance.

Air enters the connector of inlet pipes. Tighten connected screws or seal the connector.
Damage or leakage of sealing elements is severe. Tighten or change sealing elements.
Air enters pipes of the pump body. Eliminate the air.
Incorrect setting of the stroke. Adjust the setting of the stroke


Lax close of check valves of the inlet and outlet. Check the valve seat and clean

or change the valve ball.

The gasket in the check valves of the inlet and outlet leaks. Check the sealing face and

change the seal ring.

Incorrect operating speed of the pump. Match power voltage and

frequency with the values on

the label of the pump motor.

Leakage of the pipette. Repair or change the pipette.
The liquid is close to the boiling point. Cool liquid or increase

pipette heads.

The liquid viscosity is too high. Reduce the viscosity(such as

heating or diluting the liquid).





Measuring accuracy falls.

Same as the reasons above. Eliminate according to the

appropriate methods above.

Unstable motor speed. Stabilize frequency and voltage

of the electric valve.

Screws in the flow rate adjustment wear or sprang. Change wear-out parts or

find out reasons to eliminate.


The vibration and

noise of the

drive reducer.

Pump overloads. Reduce the workload.
Packing is too tight and the hot friction is too high. Relax or change the packing.
Worm plays. Find out reasons to eliminate.
Gaps between transmission parts increase. Find our reasons to adjust gaps

or change wear-out parts.



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