[2026 Pump Operation] Common misunderstandings about low-frequency operation of industrial pumps (3)
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Myth 3: All pumps can operate at low frequency. There is no distinction between different types of pumps, and their tolerance to low-frequency operation varies greatly. The centrifugal pump can still operate at reduced frequency within a certain range (usually not less than 30Hz), but it cannot deviate from the rated frequency for a long time. ； Due to the structural characteristics of positive displacement pumps such as gear pumps and screw pumps, low-frequency operation will lead to insufficient medium pressure in the pump, which is more likely to cause cavitation and mechanical wear. Deep frequency conversion is not recommended at all. Many companies ignore this difference and blindly reduce frequency, causing equipment to be scrapped early.
The following is for reference: Simply put, an industrial pump is a mechanical device that converts mechanical energy into hydraulic energy and is used to transport liquids (such as water, crude oil, chemical raw materials, etc.) or change the flow direction of liquids. It is one of the indispensable core devices in the national economy. Its family is very large and can be divided into centrifugal pumps, screw pumps, gear pumps, mixed flow pumps, etc. according to their working principles. Different types of pumps adapt to different working conditions. For example, centrifugal pumps are widely used for ordinary liquid transportation, screw pumps are suitable for high-viscosity media, and mixed flow pumps take into account the characteristics of centrifugal pumps and axial flow pumps, and are often used in the field of water treatment.
Compared with ordinary civilian pumps (such as household booster pumps), industrial pumps have the characteristics of large flow, high pressure, strong corrosion resistance, and high operational stability requirements. The core components include pump bodies, impellers, seals, drive motors, etc. The normal operation of each component is directly related to production safety.
The role of industrial pumps runs through the entire process of industrial production and can be called the "lifeline of the production line". It is mainly reflected in three aspects:: ◉ Material transportation: This is the core function of accurately transporting liquid media such as raw materials, semi-finished products, and finished products between different equipment and different processes, such as transporting crude oil and chemical products in the petrochemical industry, transporting cooling water and lubricating oil in the power industry, and transporting sewage and clean water in the water treatment industry.
◉ Energy conversion and pressure regulation: Convert the mechanical energy of the motor into the pressure energy and kinetic energy of the liquid, allowing the liquid to overcome resistance such as gravity and pipeline friction and transport it to the designated location ； At the same time, the flow and pressure within the system can be adjusted to provide precise control of the production process.
◉ System circulation and cooling: In industrial circulation systems (such as air-conditioning hot and cold water circulation, equipment cooling circulation), industrial pumps are responsible for promoting the circulation of media, taking away the heat generated by the equipment, ensuring long-term stable operation of the equipment, and avoiding damage due to overheating.
It can be said that without the stable operation of industrial pumps, most industrial production will come to a standstill. Low-frequency operation is the "invisible killer" that destroys this stability.
In daily working conditions, why does the pump fall into low-frequency operation? There are 4 main common reasons, which should be avoided in a targeted manner: 1. Blind pursuit of energy saving and artificial frequency reduction: This is the main reason. In order to reduce energy consumption costs, many companies arbitrarily reduce the operating frequency of pumps through frequency converters without professional evaluation, ignoring the rated working condition requirements of the pumps, resulting in long-term low-frequency operation.
2. Unreasonable system design and selection deviation: The selection of the pump is too high, for example, the rated head and flow rate are much greater than the actual production demand, resulting in the pump being in a "big horse-drawn cart" state for a long time, and being forced to operate at low frequency to match the system demand. ； Or the pipeline design is unreasonable, and there are problems such as sharp bends and diameter reductions, which increase hydraulic losses and indirectly lead to low-frequency operation of the pump.
3. Load fluctuation, passive low frequency: Some production processes have unstable loads. When the production load decreases, the system's demand for flow and pressure also decreases. If the operating mode of the pump is not adjusted in time, the pump will passively enter a low-frequency operation state and cannot restore the rated speed for a long time.
4. Improper operation and wrong parameter settings: The operators are not familiar with the parameter settings of the frequency conversion equipment. For example, the minimum operating frequency is set too low (less than 30Hz), or the parameters are not adjusted according to changes in medium characteristics and working conditions, resulting in the pump operating in an unreasonable low-frequency range for a long time.