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.

The fire pump has become the most widely used fire pump because of its simple structure, convenient use and maintenance, and high efficiency. However, sometimes the centrifugal fire pump cannot lift water, which is very troublesome. The cause of the failure of the fire pump to lift water is now analyzed.

The speed of the fire pump is too low

(1) Human factors. Due to the damage of the original motor, a considerable number of users randomly equipped the fire pump with another motor to drive it. As a result, the flow rate was low, the head was low, and even the water could not be pumped.

(2) The transmission belt is worn. There are many large-scale isolated fire pumps that use belt transmission. Due to long-term use, the drive belt is worn and loosened, and slipping occurs, thereby reducing the speed of the fire pump.

(3) Improper installation. The distance between the centers of the two pulleys is too small or the two shafts are not parallel, the fire pump transmission belt is installed on the tight side, resulting in too small wrap angle, the calculation error of the diameter of the two pulleys, and the large eccentricity of the two shafts of the fire pump driven by the shaft, etc. Both will cause changes in fire pump speed.

(4) Mechanical failure of the fire pump itself. The fastening nut between the impeller and the pump shaft is loose or the pump shaft is deformed and bent, causing the impeller to move more, directly rubbing against the pump body, or the bearing is damaged, which may reduce the speed of the fire pump.

(5) Improper maintenance of fire pump power machine. The motor loses its magnetism due to the burning of the windings, the number of winding turns, wire diameter, and wiring method changes during maintenance, and the failure of the fire pump or maintenance to completely eliminate factors will also change the speed of the fire pump.

The second way to solve the fire pump failure:

Some users have measured that although the vertical distance from the water reservoir or water tower to the water surface of the fire pump is slightly smaller than the lift of the fire pump, the water capacity is still small or cannot be lifted. The reason for the fire pump is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of the water flow in the pipeline is too large. The reason is often that the pipeline is too long, there are many bends in the water pipe, and the resistance loss of the water flow in the pipeline is too large. In general, the resistance of the 90-degree elbow is greater than that of the 120-degree elbow, and the head loss of each 90-degree elbow is about 0.5 to 1 meter, and the resistance of each 20-meter pipe can cause a head loss of about 1 meter. In addition, some users also choose the diameter of the inlet and outlet pipes of the fire pump at will, which also has a certain impact on the lift.

(1) Some users do not fill enough water before starting the fire pump; sometimes it seems that the filled water has overflowed from the vent hole, but the air is completely discharged without turning the pump shaft, resulting in a little air remaining in the water inlet pipe or pump body middle.

(2) The horizontal section of the inlet pipe that is in contact with the fire pump shall apply a descending slope of more than 0.5% against the direction of water flow, and the end connected to the inlet of the fire pump shall be the highest, and shall not be completely horizontal. If it is tilted up, air will remain in the water inlet pipe, which will reduce the vacuum in the water pipe and fire pump, and affect water absorption.

(3) The packing of the fire pump has been worn out due to long-term use or the packing is too loose, causing a large amount of water to spray out from the gap between the packing and the pump shaft sleeve. As a result, the external air enters the fire pump from these gaps. The inside of the pump, which affects the pumping of water.

(4) The water inlet pipe has been underwater for a long time, and the pipe wall has corroded holes. After the fire pump works, the water level continues to drop. When these holes are exposed to the water surface, air enters the water inlet pipe through the holes.

The flow value of the stabilized pump depends on many factors, the main ones are:

(1) Type of system When the stabilized pump is used in a self-spray system, consider the water volume of a sprinkler; and when it is used in a fire hydrant system, consider the water volume of a fire hydrant.

(2) When there is an air pressure water tank and an air pressure water tank, the flow rate of the pressure stabilizing pump is not greater than the water volume of a nozzle or a fire hydrant. When there is an air pressure water tank, the water supply and pressure guarantee of the system are implemented by the air pressure water tank, and the flow rate of the pressure stabilizing pump only needs to meet the flow requirements of the air pressure water tank, that is, the flow rate of the pressure stabilizing pump should take into account the pressure of the air pressure water tank. Factor for adjusting the volume of the tank. At this time, the flow rate of the pressure stabilizing pump should be calculated and determined according to the calculation formula of the total volume of air and water in the tank of the air pressure water supply equipment and the volume of water in the tank. The water output of the water pump should be not less than 1.2 times the hourly flow of the pipe network when the tank is at the average pressure.

There is no provision in the "High Regulations" that the air pressure water tank must be equipped, but without the air pressure water tank, the voltage stabilizing pump starts frequently and is easy to be damaged; with the air pressure water tank, the problem of the pressure stabilizing pump starting frequently can be alleviated, and the voltage stabilization work of the system can be alleviated. The guarantee of the situation can be better reflected. However, the cost of the air pressure water tank needs to be increased. In general, the volume of the air pressure water tank provided with the equipment does not need to be too large, and the volume should be less than 50L. Shanghai has compiled a standard atlas of pressure-stabilizing pumps for supporting air-pressure water tanks.

(3) System scope The quasi-high-pressure water supply system (or called the high-pressure water supply system) with a stabilizing pump can range from indoor to indoor and outdoor. Indoor quasi-high pressure water supply system, the pipe is made of steel pipe, and the interface is connected by thread, flange or welding. The leakage of the pipe network system mainly occurs in the sealing part of the water pump, and its quantity is relatively limited. In the indoor and outdoor quasi-high pressure water supply system, since the outdoor pipes are made of cast iron, the interface adopts socket connection, and the interface seal adopts rubber ring. Immediately after the construction of the pipeline, the soil is covered, and sometimes the interface is reinforced with concrete enclosure. Even if there is leakage, it is difficult to take remedial measures. All these show that when the quasi-high pressure water supply system is used indoors and outdoors, there should be enough room for the flow rate of the stabilizing pump.