1. List the basic data:

1, the characteristics of medium: medium name, specific gravity, viscosity, corrosiveness and toxicity.

2. The diameter and content of solid particles in the South China pump industry (mass or volume percentage).

3, medium temperature: (centigrade)

4. Flow of demand

Usually, industrial pumps can ignore leakage in piping system, but it is necessary for pumps to think about the effect of skills change on flow. If the agricultural pump is to use the open channel to transport water, it is also necessary to consider the leakage and evaporation.

5, pressure: pressure drop (head loss) in suction tank, drainage pool and pressure piping system.

6. Pipeline system data (pipe diameter, length, variety and number of pipe accessories and number of suction sump to pressure tank). If demand is required, the equipment characteristic curve should be made for the following items.

A, a reasonable selection of pipe diameter in the same flow, small flow velocity, small drag loss and low pipe diameter will cause a sharp increase in resistance loss, which makes the pump's lift added with the added power to add the cost and the cost of operation so that it should be summed up from the viewpoint of skill and economy.

B, discharge pipe and its connection shall consider the maximum pressure that can bear.

C, pipe placement should be placed into the tube as far as possible to minimize the accessories in the pipe and minimize the length of the pipe. The bending radius of the time - time elbow should be 3~5 times the diameter of the pipe as much as 90 degrees.

D, the discharge side of the pump is necessary to install the valve (ball valve or cut-off valve, etc.) and the reverse check valve valve used to regulate the pump's operating point. The reverse check valve can prevent the pump from turning and prevent the impact of the water hammer when the liquid reflows.

Two. Determine the flow head

The determination of the flow rate

A, if the minimum, normal and maximum flow rate has been given in production skill, we should consider the maximum flow rate.

B, if the production skills only give the normal flow rate, we should think about a certain allowance for the large flow rate of ns>100, the flow margin of the pump flow rate of 5% to ns>50, the pump flow allowance of 10%50 less than ns < < < < < < ns < < < < < < 100 >, the flow allowance of the pump is 5% pairs of poor quality and the bad pump flow allowance of the running bar should be taken.

C, if the basic data is only to the component traffic, it should be converted into volume flow.

Notice

1. Device leakage protector

The leakage protector is also called the lifesaving device. Its function can be understood from the three words of "lifesaving device". Because submersible pump works underwater, simple leakage leads to loss of electric energy and even electric shock. If the leakage protector is equipped, only the leakage value of the submersible pump exceeds the action current of the leakage protector (usually does not exceed 30 MA), the leakage protector will block the power of the submersible pump, prevent leakage of electricity and ensure safety.

2. The power supply voltage is abnormal.

Because the low voltage power supply line is long, the voltage at the end of the line is too low. When the phase voltage is below 198 volts and the line voltage is less than 342 volts, the motor speed of the submersible pump is reduced. When the extra speed is not reached to 70%, the centrifugal switch will be closed. On the contrary, too high voltage causes the motor to overheat and burn the winding. Therefore, in the operation of the submersible pump, it is necessary for the operator to investigate the voltage of the power supply at any time. If it is below 10% of the extra voltage and above 10% of the extra voltage, the motor should be discontinued, and the factors can be found out and the fault is excluded.

3. Prevent frequency switch

Do not switch the submersible pump frequently, this is because the electric pump stops to turn back, if that is to start, the motor load will be launched, causing excessive current and burning the winding. Because the current is very large at startup, it will destroy the motor winding of submersible pump when firing frequently.

4, do not let the submersible pump long time overload operation

In order to prevent the long time overloading of the submersible pump, do not pump the water containing a large amount of sand and investigate the value of the current value at any time in the nameplate. If the current is too large, it should be stopped and checked. In addition, the time of dewatering and running of the electric pump should not be too long, so as to avoid overheating the motor and burn it down.

5, the rotation direction of the motor should be accurate

The rotation direction of the motor should be made clear. There are many types of submersible pumps that can be turned out and turn out when they turn, but the output of the motor is small and the current is large, and the motor winding will be damaged by the turning time.

6, the insulation resistance request of cable device and submersible pump.

When submersible pump is installed, the cable should be overhead and the power cord should not be too long. When submersible pump is launched or put forward, do not force the cable to avoid breaking the power line. Don't sink into the mud when submersible pump operation, otherwise it will cause bad heat dissipation and burn out motor windings. When the device is installed, the insulation resistance of the motor should not be less than 500 billion euro.

7, Qin Chaqin see correction problem in time

Usually look at the motor frequently. If we find cracks on the lower cover and damage or failure of the rubber seal ring, we should replace or correct it in time to prevent water from entering the submersible pump.