The basis for fire pump selection should be based on the process flow, water supply and drainage requirements, and consider five aspects, namely, liquid delivery volume, device lift, liquid properties, pipeline layout, and operating conditions.
1. The head required by the installation system is another important performance data for the selection of fire pumps. Generally, the head needs to be enlarged by 5%-10% to select the type.

2. The flow rate is one of the important performance data for selecting a fire pump, which is directly related to the production capacity and delivery capacity of the entire device.

3. The pipeline layout conditions of the device system refer to some data such as the height of the liquid delivery, the distance of the liquid delivery, the direction of the liquid delivery, the lowest liquid level on the suction side, the highest liquid level on the discharge side, etc., as well as the pipe specifications and their length, material, pipe fitting specifications, and quantity etc., in order to carry out the calculation of the comb head and the check of NPSH.

4. Liquid properties, including the name of the liquid medium, physical properties, chemical properties and other properties. Physical properties include temperature c density d, viscosity u, solid particle diameter and gas content in the medium, etc., which relate to the head of the system, effective gas Calculation of corrosion residue and suitable pump type: Chemical properties mainly refer to the chemical corrosion and toxicity of the liquid medium, which is an important basis for selecting the pump material and the type of shaft seal.

5. There are many operating conditions, such as liquid operation T, saturated steam force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and the position of the fire pump is Fixed or removable.

What is the problem with the fire pump vibrating or abnormal sound, and how to solve it?
The fire-fighting water provided by most fire-fighting water sources needs to be pressurized by fire-fighting water pumps to meet the requirements for water pressure and water volume during fire-fighting, which is an important part of fire-fighting. In daily use, we often encounter fire pumps vibrating or making abnormal noises. What is the problem? How should we solve it?
1. The installation is not firm and the fasteners are loose

After the centrifugal fire pump is started, the impeller will rotate at a high speed. The centrifugal fire pump is not installed firmly, or the fasteners are loosened due to long-term operation, which will cause vibration and noise during the operation of the pump, and even be damaged in a short time.

2. Wear between impeller and seal ring

If the impeller and the sealing ring cannot guarantee a good lubrication state, the wear between the two will increase the gap, and when the gap exceeds a certain value, the pump will cause vibration and noise. The degree of wear increases as the pump runs longer.

3. Improper installation of pump body and pump shaft

The effective energy obtained by the liquid passing through the fire pump is obtained from the impeller of the pump, and the energy obtained by the impeller is obtained from the pump shaft, and the energy obtained by the pump shaft is provided by the motor. When the pump is running, the pump shaft drives the impeller to rotate at high speed. If the pump body and the pump shaft are not installed correctly, the impeller will deviate from the friction with the pump casing, resulting in vibration, and in severe cases, the impeller and pump casing will be damaged.

4. Cavitation causes abnormal sound inside the pump

Excessive resistance of the suction pipeline, leakage of air due to poor sealing, excessive temperature of the liquid being sucked, high flow rate, etc., will cause cavitation, which will cause abnormal sound or severe vibration in the pump.

If your fire pump has vibration and abnormal noise during use, you can refer to the above points to check one by one, and you can easily find out the problem and solve it.

The overload of the fire pump means that the work exceeds the rated power. If the work exceeds the rated power for a long time, it will cause damage to the water pump and shorten the service life of the fire pump. For fire pump overload, there are certain installation requirements, and there are certain regulations on selection and application. Zjbetter fire pump manufacturer will talk with you about the overload of fire pumps.

First, the installation requirements of the fire pump
1. Noise-absorbing check valves, control valves and pressure gauges should be installed on the outlet pipes of fire pumps; pressure gauges and pressure switches should also be installed on the main outlet pipes of the system; buffer devices should be added when installing pressure gauges. A cock should be installed between the pressure gauge and the buffer device; the range of the pressure gauge should be 2 to 2.5 times the working pressure of the system if there is no design requirement.

2. The selection and application of fire pumps should meet the following requirements:
1) The power of the driver equipped with the fire pump should meet the power requirements for operation at any point on the selected pump flow head performance curve.

2) The performance of the fire pump should meet the flow and pressure requirements of the fire water supply system.

3) When the outlet flow is 150% of the design flow, the outlet pressure should not be lower than 65% of the design working pressure.
5) When a motor-driven fire pump is used, a dry-installed fire pump with a motor should be selected. 4) The flow head performance curve should be a smooth curve without humps and inflection points, and the pressure at zero flow should not be greater than 140% of the design working pressure, and should be greater than 120% of the design working pressure.
6) The models of fire pumps in the same pump group for fire water supply should be the same, and there should be no more than 3 working pumps.
7) The sealing method and material of the pump shaft should meet the requirements for the fire pump to operate at low flow.
8) When multiple fire pumps are connected in parallel, the effect of flow superposition on the outlet pressure of fire pumps should be checked.

As we all know, fire-fighting equipment is basically not in operation at ordinary times, and the emergency equipment that is activated only when a fire breaks out can be described as equipment that "raises troops for a thousand days and uses them for a while". However, since the fire pump does not start for a long time and is in a dark and humid environment all the year round, it often happens that the fire pump cannot be started in time in an emergency. At this time, the importance of the fire inspection cabinet is reflected. This is why we recommend that you install a fire inspection cabinet.

The automatic inspection cabinet is an important part of the fire protection system. It mainly conducts regular and fixed speed inspections on the fire pumps to keep the fire pumps in a reliable operating state for a long time.

The installation of the fire pump requires a strict seal between the pump body and the pipeline, and a strict seal between the pump casing and the pump shaft. If the seal is not tight, leakage may occur. Or the water seepage and water leakage problems that may occur after long-term use of the fire pump, most of which are caused by the aging and wear of the sealing equipment of the fire pump. A large amount of liquid is leaked, which may affect the delivery capacity of the pump, so how to quickly solve the above-mentioned water leakage problem?

There are many ways to maintain fire pumps and water pumps. The following methods are more effective. You can use them for reference:

Method 1: The installation of the pump set should be accurate and reliable, and there should be no obvious vibration during operation. If the pump makes abnormal noise when pumping water, or the bearing is hot to the touch (the temperature is higher than 60°C) and the water seepage in the seal of the pump shaft is more than 60 drops per minute, the cause must be found out and the fault should be eliminated in time.
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Method 2: Screws that are screwed daily, such as packing gland screws, irrigation plugs, etc., should be disassembled with a suitable wrench and a reasonable torque. You can put some lubricating oil on it or wipe it regularly with an oil cloth to prevent rust; if the water drain screw is not used frequently, it is easy to rust, so after buying a new water pump, you should first unscrew the water drain plug, and apply some machine oil and white lead oil on the screw thread , Change the new oil two or three times a year in the future.
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Method 3: If the pump is lubricated with engine oil, the lubricating oil should be replaced once a month; if it is lubricated with butter, it should be replaced every six months. It should be noted that the water pump uses calcium-based grease, and the motor uses sodium-based grease, and they should not be used incorrectly. Because sodium-based grease is hydrophilic, it will emulsify into foam and dissipate when it encounters water on the pump, while calcium-based grease is afraid of high temperature, so it is easy to melt when the temperature rises when used on a motor.

Method 4: Do not pump water with too much sand, so as to avoid premature wear of the impeller, mouth ring and shaft, and try to prevent water shortage operation. Running without water will damage the water seal, and the water pump is prone to water leakage or even no water.

Method 5: After the irrigation and drainage season is over, the water pump should be carefully cleaned and inspected immediately. If any damaged or deformed parts are found to be unusable, they should be repaired or replaced in time, and the parts that should be lubricated should be filled with suitable oil; Best stored in a dry place.