FluidTech News

Plunger vs. Diaphragm Metering Pumps: How to Choose for Water Treatment Dosing Metering pumps are widely used in water treatment systems to inject chemicals accurately and continuously. Two common options are plunger metering pumps and diaphragm metering pumps. So, which one is better? The answer depends mainly on the chemical, pressure, flow rate and safety requirements. 1. Plunger Metering Pump: Strong Pressure Performance A plunger metering pump uses the reciprocating movement of a plunger to draw in and discharge the liquid. Its main advantages include: High discharge pressure capability Accurate and stable dosing Relatively direct mechanical structure Suitable for stable and less corrosive liquids For applications where the chemical is relatively stable and the system requires higher pressure, a plunger metering pump can be a practical choice. However, its sealing structure requires particular attention when handling corrosive, toxic or hazardous chemicals. 2. Diaphragm Metering P...

 Why Does a Liquid Ring Vacuum Pump Need Circulating Water? Key Operating Factors for Stable Vacuum Performance Liquid ring vacuum pumps are widely used in chemical processing, vacuum filtration, evaporation, drying, degassing, power generation, and many other industrial vacuum systems. Unlike many dry vacuum technologies, a water-ring vacuum pump depends on a continuous supply of operating liquid—most commonly water. This often leads to a practical question: Why is circulating water so important, and what happens when its flow rate or temperature is incorrect? The answer is simple: water is not merely a cooling medium. It is an active part of the vacuum-generation process. The Water Ring Is Part of the Pumping Mechanism Inside a liquid ring vacuum pump, the impeller is installed eccentrically relative to the pump casing. When the impeller rotates, centrifugal force pushes the operating liquid toward the outer wall of the casing, creating a rotating liquid ring. Because of the ecce...

Why Does the Operating Current of a Submersible Pump Increase? Common Causes and Troubleshooting Methods Submersible pumps are widely used in wastewater treatment, drainage systems, industrial water supply, construction projects, and underground water pumping applications. During normal operation, the motor current of a submersible pump should remain within the rated range. However, after a period of operation, some users may notice: Increasing motor current; Higher motor temperature; Abnormal vibration or noise; Frequent overload protection trips. These symptoms indicate that the pump may be operating under abnormal conditions. So, why does the operating current of a submersible pump increase? What factors cause the motor load to rise? 1. Increased Load Caused by Changes in Pumping Medium The operating current of a submersible pump is closely related to the motor load. When the characteristics of the pumped liquid change, the resistance inside the pump system may increase. Common situ...

 Why Must a Screw Pump Never Run Dry? Causes of Stator Damage Explained Screw pumps are widely used for transferring high-viscosity liquids, sludge, wastewater, chemicals, food products, and other difficult-to-handle media. Compared with many conventional pumps, they can maintain relatively stable flow even when handling viscous or particle-containing fluids. However, there is one operating rule that should never be ignored: A screw pump should not be started or operated without sufficient medium inside the pump. Why is dry running so dangerous? The main reason lies in the working relationship between the rotor and stator. How Does a Screw Pump Work? In a typical single screw pump, also known as a progressive cavity pump, the main pumping elements are: A metallic rotor An elastic stator As the rotor rotates inside the stator, a series of sealed cavities is formed. These cavities continuously move from the suction side toward the discharge side, carrying the medium through the pump....

Why Does a Diaphragm Pump Outlet Pressure Fluctuate? Causes and Solutions for Stable Operation In industrial fluid transfer systems, air operated diaphragm pumps are widely used in chemical processing, wastewater treatment, electroplating, food, pharmaceutical, and other industries due to their excellent corrosion resistance, self-priming ability, and capability of handling complex fluids. However, during actual operation, some users may find that the outlet pressure of a diaphragm pump is unstable. Typical symptoms include: Pressure gauge pointer fluctuates continuously; Discharge pressure rises and falls periodically; Downstream equipment cannot maintain stable operation. What causes diaphragm pump pressure fluctuation? How can the pump achieve more stable operation? Shanghai Shangcheng Pump & Valve analyzes the main causes and practical solutions. 1. Unstable Air Supply Pressure For air operated diaphragm pumps, compressed air is the driving power. If the air supply system canno...

 Why Does a Diaphragm Pump Flow Rate Decrease After Long-Term Operation? Causes and Solutions Diaphragm pumps are widely used in chemical processing, wastewater treatment, pharmaceutical, food processing, coatings, and other industries because of their excellent ability to handle high-viscosity fluids, corrosive liquids, and media containing particles. However, during actual operation, many users encounter a common problem: The diaphragm pump works normally at the beginning, but after running for a period of time, the flow rate gradually decreases. Why does this happen? A reduced flow rate does not always mean the pump selection is wrong. In most cases, it is related to air supply conditions, wear of internal components, medium characteristics, or improper maintenance. Shanghai Shangcheng Pump & Valve analyzes the common reasons and solutions for diaphragm pump flow reduction. 1. Insufficient Air Supply Pressure Causes Flow Reduction For air operated diaphragm pumps, compressed...