FluidTech News

 Can Screw Pumps Run Dry? Structural Differences Explained In many industrial sites, operators sometimes assume that “a few minutes of dry running won’t hurt.” But when it comes to screw pumps, the reality is very different. Whether a screw pump can tolerate dry running depends entirely on its internal structure. Making the wrong assumption can result in rapid wear, seal failure, or even complete pump damage. What Is Dry Running? Dry running occurs when a pump operates without sufficient liquid inside the casing for lubrication and cooling. Common causes include: Starting without priming Low tank level Blocked suction line Intermittent material supply For positive displacement pumps like screw pumps, this is a high-risk condition. 1️⃣ Single Screw Pump (Progressive Cavity Pump) Structure: Metal rotor Elastomer stator Sealed cavities formed between rotor and stator This design relies heavily on the pumped fluid for lubrication and cooling. If dry running occurs: Friction temperature...

 How the Balance Disc Protects a Multistage Pump When people talk about multistage centrifugal pumps, they usually focus on head, efficiency, or mechanical seals. But in high-head applications, one critical component determines long-term reliability: the balance disc. In every multistage pump, each impeller generates axial thrust. As the number of stages increases, the axial force accumulates. Without an effective balancing device, this force can: Overload the thrust bearing Cause shaft axial movement Damage mechanical seals Increase vibration and shorten service life That’s why a properly designed balance system is essential. What Does a Balance Disc Do? The balance disc is a hydraulic axial force compensation device. Its job is simple in theory but sophisticated in operation: It uses pressure differential to generate a counteracting force. High-pressure liquid from the pump discharge enters the balance chamber. A small clearance between the balance disc and balance ring allows co...

 Operating a Centrifugal Pump at Minimum Flow — Hidden Risks Many Plants Overlook Centrifugal pumps are widely used in water supply, chemical processing, cooling circulation, and industrial fluid transfer systems. However, in many facilities, pumps are operated for long periods under minimum or low-flow conditions simply by throttling the discharge valve. Although the pump may appear to run normally, this operating method can gradually damage internal components and significantly reduce service life. In practical engineering applications, manufacturers such as Shanghai Shangcheng Pump & Valve often find that premature pump failures are caused not by product quality, but by long-term operation away from the designed flow range. 👉 Learn more about centrifugal pump solutions: https://www.scpv.cn/lixinbeng/ 1. Excess Heat Build-Up Inside the Pump A centrifugal pump relies on flowing liquid to remove heat generated during operation. When operating below minimum flow: Liquid continu...

 Hidden Risks of Wrong Chemical Pump Material Selection — A Long-Term Cost Many Plants Ignore In chemical processing systems, pump performance is not determined only by flow rate or pressure. In reality, material selection is the most critical factor affecting long-term reliability. Many industrial failures are not caused by poor manufacturing quality, but by incorrect material matching during the early selection stage. Manufacturers such as Shanghai Shangcheng Pump & Valve emphasize evaluating fluid characteristics before choosing pump models, because improper materials can create long-term operational risks. 👉 Chemical Pump Solutions: https://www.scpv.cn/huagongbeng/ 1. Corrosion Problems Often Appear Later A chemical pump may operate normally during initial installation. However, after several months of operation, hidden corrosion begins to appear. Common consequences include: Pump casing corrosion Impeller thinning Reduced hydraulic efficiency Chemical media such as acids,...

 How Stroke Length Adjustment Controls Metering Pump Accuracy In chemical dosing, water treatment, and industrial injection systems, a metering pump is valued for one key capability — precise flow control. Many users assume flow adjustment depends on motor speed. In reality, most metering pumps regulate flow by changing the stroke length. What Is Stroke Length in a Metering Pump? Stroke length refers to the moving distance of the diaphragm or plunger during one reciprocating cycle. The principle is straightforward: Longer stroke → larger discharge volume per cycle Shorter stroke → smaller discharge volume Constant speed → stable dosing frequency So the output flow rate is mainly controlled by adjusting how much liquid is displaced in each stroke. Mechanical Principle Behind Stroke Adjustment Inside a metering pump, rotational motion from the motor is converted into reciprocating motion through: Eccentric cam mechanism Connecting rod system Diaphragm or plunger assembly When the adj...

 Rotary Pump Volumetric Efficiency: What It Is and How to Calculate It Rotary pumps are widely used across industrial sectors — from chemical dosing to lubrication systems — because they deliver relatively steady flow and handle a range of viscosities. Yet, a question engineers frequently encounter is: Why is the actual flow lower than the expected value on paper? The answer often points to one critical performance metric: volumetric efficiency. Understanding how to calculate and interpret this efficiency can help you distinguish between equipment faults and system design limitations. What Is Volumetric Efficiency? Volumetric efficiency (ηv) describes how closely a pump’s actual performance matches its ideal theoretical delivery. In a perfect world, a rotary pump would deliver exactly the liquid volume defined by its geometry and running speed. But in reality, internal leakage, compressibility effects, and pressure losses reduce the actual output. The classic formula is: Volumetric...