The twin-screw pump is a type of volumetric pump that relies on the rotation of two intermeshing screws within the pump chamber to create a sealed cavity, thereby enabling continuous and stable delivery of the medium. Its key features include no pulsation, high efficiency, and the ability to handle high pressure. It is widely used in industries such as petroleum, chemical engineering, shipping, and food.
Product structure features
Two identical-sized screws: the driving screw and the driven screw, achieving meshing rotation through synchronous gears.
Non-contact operation: There is no direct contact between the screws, maintaining a gap of 0.05-0.15mm, resulting in low wear and long service life.
Extraneous bearing structure: Supports independent lubrication and can adapt to non-lubricable media (water, solvents, polymer solutions).
Axial push of sealed chamber: When the screw rotates, the medium is enclosed between the helical groove and the pump body, forming a continuous sealed chamber, advancing axially without backflow, with highly stable flow and almost no pulsation.
Core selling point
Pulsation-free transportation - Two screws rotate synchronously, ensuring highly stable flow with almost no pulsation, suitable for precise metering (such as fuel injection, chemical dosing)
High-pressure transportation - Working pressure can reach 4-6 MPa (higher than single screw pumps), up to 1.4-7 MPa for high-viscosity liquids
Strong self-priming ability - Dry suction height can reach 5-8 meters (superior to gear pumps), enabling the pump to suck in liquids without priming
High viscosity adaptation - Can transport media with viscosity up to 1.5×10⁶ cSt (Depamu series), with a conventional limit of 1500 mm²/s, ranging from light solvents to heavy asphalt and polymer melts
Heating jacket optional - The pump body can be equipped with a bottom heating jacket, suitable for the transportation of high-viscosity fluids (such as heavy oil, asphalt, chocolate)
Material flexibility - Pump body: ductile iron/cast steel/304/316L/dual-phase steel; Screw: 38CrMoAlA nitrided steel/stainless steel/dual-phase steel; Shaft seal: single-end face/multi-end face mechanical seal/packing seal
Built-in safety valve - Internal safety valve protects the pump system from damage under abnormal pressure
Application scenario
The key feature of the twin-screw pump is "high viscosity / gas-containing / multiphase / non-lubricating medium + pulsation-free stable transportation". Core scenarios:
Oil & Energy (maximum single unit)
Crude oil transportation: crude oil with a small amount of solid particles (particle diameter 0.12 - 0.2mm), multiphase mixed transportation (gas content ≤ 80%)
Fuel oil / heavy oil loading and unloading: heated jacket insulation, viscosity up to 1500 mm²/s
Bitumen / asphalt circulation: high-temperature type (≤ 350℃), heated jacket
Oil and gas mixed transportation: maximum gas content 98%
Coal water slurry, resin, additive transportation
Oilfield drilling mud
Ship transportation
Fuel supply (MFO/HFO): high viscosity, containing impurities, non-contact structure of twin-screw pump + external bearings is an ideal choice
Sump pump: oily wastewater, containing solid particles
Oil-water separator: oil-water mixed transportation
Ship incinerator transportation pump
Oil treatment in machine room
Chemical industry
Solvents, polymers, high-viscosity chemical raw materials transportation
Acid-base salt solutions, viscous chemical pastes
Emulsions, slurries
Multiphase mixed fluid transmission
Polymer additive metering (Depamu non-standard product can transport up to 300,000 mm²/s of polymer)
OEM/ODM
Medium characteristics: viscosity (cSt), temperature, density, volatility, presence of gas/vapor, presence of solid particles and particle size, corrosiveness (pH value, chloride ion content)
Operating conditions parameters: flow rate Q × outlet pressure P (pressure of positive displacement pumps is determined by system back pressure)
Installation method: horizontal (B3 base) vs vertical (V1 flange)
Standard compliance: general industry vs API 676 (petrochemicals) vs food grade (FDA/EHEDG) vs explosion-proof (ATEX)
Material route: crude oil/heavy oil → cast iron/carbon steel; food and medicine → 304/316 stainless steel; chemical corrosion → 316/dual phase steel; high temperature → with insulation jacket
Sealing type: single-end face mechanical seal (standard) vs double-end face mechanical seal (dangerous media)
Auxiliary systems: synchronous gear transmission (WTG, no metal contact) vs asynchronous gear (NTG, screw contact, suitable for high viscosity and high temperature)
Customized Services: Design based on provided drawings and samples, OEM brand logo, API 676 compliance design, ATEX explosion-proof certification, heating jacket, special materials (duplex steel/Hastelloy/Circular stainless steel), special seals (double-end mechanical seal + barrier fluid system), variable frequency speed control, CIP/SIP hygienic design, complete packaged unit (pump + motor + base + coupling + safety valve + instrument valves), remote monitoring system.
Supplier Introduction
CZME is a world-class manufacturer of high-performance pumping solutions, serving industries such as mining, construction, environmental protection, and water treatment. We specialize in the production of Slurry pumps, Dredge pumps, Desulfurization pump, Marine dredging pumps, and other industrial pumps designed for handling solid-laden, highly abrasive, and corrosive slurries. Our expertise in slurry and wastewater management makes us a trusted partner for clients worldwide.
FAQs
Q: How to choose between a twin-screw pump and a triple-screw pump?
A: High viscosity + gas-containing + multiphase + non-lubricating medium → Twin-screw pump (pressure 1.4 - 7 MPa, viscosity up to 1.5×10⁶ cSt, gas content ≤ 80%); Clean lubricating oil/hydraulic oil with high pressure and small flow rate → Triple-screw pump (pressure up to 28 MPa, flow rate 0.2 - 320 m³/h, but strict cleanliness requirements for the medium) <citation:2>. In simple terms: Twin-screw pump is a "all-rounder", while triple-screw pump is a "expert in high-pressure clean medium".
Q: Can a twin-screw pump convey water?
A: Yes. The twin-screw pump uses an external bearing + synchronous gear transmission, with the screws running without contact, which can adapt to non-lubricating media (water, solvents, etc.) - this is its key advantage over the triple-screw pump (the triple-screw pump must convey lubricating media). However, note: when conveying water, the mechanical seal requires external flushing or the selection of double-end face mechanical seal + barrier fluid.
Q: How is the flow rate of a twin-screw pump adjusted?
A: Mainly by changing the motor speed through frequency conversion, thereby linearly adjusting the flow rate (flow rate ∝ speed). It can also be adjusted by bypass valve backflow, but the energy consumption is higher. The conveying direction of the twin-screw pump can be reversed by reversing the rotation direction of the pump shaft - this feature is very useful in scenarios such as ship fuel supply where bidirectional conveying is required.
Q: Can a twin-screw pump run without power?
A: Short-term dry running is safe because the synchronous gears do not contact, but the mechanical seal still requires medium lubrication and cooling. Long-term dry running will cause the mechanical seal to burn out. It is necessary to ensure that the medium is filled in the pump chamber before the pump starts and install a dry running protector.
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