How to calibrate and adjust the safety relief valve on 2W.W pump?

The cracking pressure of the safety relief valve is typically set at 1.05 to 1.15 times the rated working pressure. During commissioning, slowly open the discharge valve and monitor the pressure gauge; the valve should open smoothly for bypass protection when the set pressure is reached. Never arbitrarily increase the setting pressure to avoid damaging the synchronous gears or causing motor overload. Ensure no leaks and stable medium temperature before adjustment.

What are the speed reduction rules for 2W.W pump when handling high viscosity fluids?

When handling fluids with significantly increased viscosity, the pump operating speed must be reduced. High viscosity causes internal shear heat accumulation and a surge in torque demand; maintaining rated speed can easily lead to cavitation, air binding, or motor burnout. It is recommended to use a variable frequency drive (VFD) to automatically adjust speed based on real-time flow feedback, ensuring stable shear ratio and transfer efficiency even at low flow rates to prevent material overheating and polymerization within the pump cavity.

How to troubleshoot shaft seal leakage on 2W.W pump?

For packing seals, check if the gland bolts are evenly tightened; allow a slight drip to form a lubricating film but strictly prohibit dry running. If using mechanical seals, regularly inspect the flow and temperature of the flushing fluid (clean oil or water) to prevent clogging by crystallization. During daily maintenance, listen for abnormal noise from the pump body; if friction sounds are detected, stop immediately to check the gear box oil level and shaft seal wear, preventing impurities from entering the seal chamber and causing scoring.

2W.W SERIES9 modelsHS: 8413.60.31

2W.W Twin-Screw Multiphase Pump (2W.W Series)

Industrial Screw Pumps•2W.W

Flow Range: 5 ~ 1200 m³/h
Pressure Range: 0.6 ~ 4 MPa
Motor Power: 5.5 ~ 315 kW
Model: 2W.W-5 → 2W.W-1200
Customs HS Code: 8413.60.31

WhatsApp Quick Quote Email for Price & DrawingModel-by-Model Technical Specifications ↓

2W.W Twin-Screw Multiphase Pump (2W.W Series)

Hydraulic Principle & Internal Construction

The 2W.W series twin-screw multiphase pump features external synchronization gears and external bearings isolated from the pumped medium. Built to API 676 standards, the counter-rotating double-ended screws transport multiphase mixtures of gas, oil, water, and entrained solids with gas volume fractions (GVF) up to 90%, making it essential for crude oil gathering and chemical terminals.

Model-by-Model Technical Specifications

Model	Inlet	Outlet	Flow (m³/h)	Pressure (MPa)	Speed (rpm)	Motor (kW)
2W.W-5	DN50	DN50	5	0.6	750	5.5
2W.W-10	DN65	DN65	10	1	750	7.5
2W.W-20	DN80	DN80	20	1	980	11
2W.W-40	DN100	DN100	40	1.6	980	22
2W.W-80	DN150	DN150	80	1.6	980	37
2W.W-150	DN200	DN200	150	2.5	1150	75
2W.W-300	DN250	DN250	300	2.5	1150	132
2W.W-600	DN300	DN300	600	4	1450	220
2W.W-1200	DN400	DN400	1200	4	1450	315

Selection guidance: match your duty point to the closest model below, then confirm with our engineers. Values are rated operating points at the listed speed.

Need Complete Engineering Dimensions & Curves?

Download the official 2W.W series 1-page technical datasheet covering all 9 model configurations.

Media Compatibility & Viscosity / Temperature Guide

Medium	Max Viscosity (cSt)	Application Note
Crude Oil (Multiphase with Gas)	100,000	Gas Volume Fraction (GVF) 85%–90%
Extra Heavy Fuel Oil / Residual Vacuum Bottoms	100,000	Harbor & Barge Tank Stripping
Polymerizable Monomers & Chemical Fluids	50,000	Chemical Fluid Transfer
Hot Bitumen / Asphalt (Jacketing Duty)	80,000	Heated Loading / Unloading Terminal Duty

International Benchmark & Interchange Guide

International Benchmarks

Leistritz (Germany) twin-screw pumps
Bornemann / PCM twin-screw multiphase pumps
API 676 compliant

Interchange Note

Twin-screw multiphase pump complying with API 676 standards. Drop-in replacement for Leistritz L2/L4, Bornemann W series, and Colfax Warren twin-screw pumps.

Materials & Shaft Seal Selection Guide

For 2W.W pump material and seal selection: When transferring sour crude oil or acidic media, use 316L stainless steel or duplex steel for the pump body to prevent corrosion. For high-temperature asphalt or polymerizing materials, the casing must be equipped with a steam-jacketed heating sleeve. For packing seals, recommend graphite braided rings with flexible packing glands to accommodate large clearance changes; mechanical seals should be selected as single or double face structures based on medium cleanliness, with flushing schemes (e.g., Plan 23 or Plan 53). If transferring heavy oil containing solid particles, wear-resistant alloy-coated screws and hard alloy seal rings should be used to extend service life.

Casing & Housing Materials: Cast Carbon Steel (WCB)Ductile Iron (GGG40 / QT450)2205 Duplex Stainless SteelAISI 316L Stainless Steel
Rotor / Gear / Screw Elements: 38CrMoAlA Ion-Nitrided Alloy ScrewsStellite Hardfaced Overlay Screws
Shaft Sealing Options: External Single/Double Mechanical Seal with Quench

Engineering FAQ

Design suction piping with a diameter equal to or larger than the pump inlet flange to minimize velocity. Install at least 3 pipe diameters of straight run before the inlet to reduce turbulence, avoiding elbows facing directly into the suction. While the 2W.W pump allows short dry running and has strong cavitation resistance, ensure NPSHa exceeds NPSHr by at least 0.5 meters for long-term safe operation of the bearing and gear oil bath system.

📐 Engineering Selection Methodology

Correct pump selection starts from the fluid, not the pump. Confirm the medium name and actual viscosity at working temperature, the required flow and differential pressure or head, suction conditions (flooded or lift), and whether the fluid crystallizes, shears, contains particles or gas. Positive displacement pumps must always be protected by a relief valve or pressure bypass on the discharge line, and must never be started against a closed valve unless a bypass is fitted. For viscous duties, derate rotational speed to preserve volumetric efficiency; for crystallizing or high-freezing-point media, specify jacketed casings with steam or thermal-oil heating. Our engineers verify each enquiry against these rules before quoting.

🏭 Manufacturing & Quality Control

Castings are produced in our own foundry cluster with material certificates for each heat number. Gear profiles, screw threads and rotor lobes are hobbed, ground and wire-cut to tolerance, then assembled with matched bearing sets. Before dispatch every pump passes casing hydrostatic pressure testing, a run-in test at rated speed on an oil bench, and relief valve cracking-pressure verification; test records are archived against the pump serial number and can be supplied with the shipment.

📦 Export Packaging & Delivery

Pumps are preserved with anti-rust coating, flanges blanked, and packed in export-grade plywood cases with steel strapping for sea freight. Document packs include operating manual, performance test record, packing list and material certificates on request. Standard models ship from stock; engineered configurations typically require 15-35 days depending on casing material and seal options. Spare rotor sets, seal kits and relief valve assemblies can be quoted together with the base pump.

Typical Applications & Industry Use Cases

The media compatibility table above maps directly to real industry duties. In lubrication circuits, size the pump for continuous duty at 70-80% of rated flow to leave margin for viscosity drift as oil warms up. In chemical transfer, confirm the medium's specific gravity and whether it is shear-sensitive before fixing rotational speed. In food and sanitary service, schedule CIP cycles around the product changeover plan and verify elastomer compliance with the relevant food-contact regulation in your market. In hot oil and asphalt service, always pre-heat the casing to the medium temperature before start-up so internal clearances are at operating dimension - a cold start against solidified product is the single most common cause of gear pump failures reported from the field.

Commissioning & Maintenance Guidance

Before first start: verify rotation direction, fill the casing with medium, open the discharge bypass, and jog the motor to confirm free rotation. Check the relief valve setting against the system design pressure and lock the adjuster. During the first hour, record suction and discharge pressures, medium temperature, and motor current - deviations from the quotation duty point usually indicate suction restriction or an over-throttled discharge line. Routine maintenance intervals: inspect the shaft seal weekly during the first month, then monthly; check coupling alignment after any pipe work; drain and inspect the bearing housing annually. Keep a log of running hours so rotors, bearings and seals can be replaced on condition rather than after failure.

Troubleshooting Quick Reference

No delivery or loss of prime: check suction line for air ingress, verify foot valve and strainer are submerged and clean, and confirm the casing is primed for pumps without self-priming capability. Flow below nameplate: verify actual rotational speed against the data sheet, confirm medium viscosity is within the rated band, and inspect internal clearances for wear if the pump has long service hours. Abnormal noise or vibration: usually coupling misalignment, cavitation from excessive suction lift, or foreign matter in the pumping chamber. Seal leakage: confirm flush plan and seal face condition; never run a mechanical seal dry. Motor overload: check for over-viscous medium at start-up temperature and confirm the relief valve is not set above the motor's capability. For anything beyond these basics, send us the serial number and symptom - our engineers will respond with a diagnosis.

📋 Standards, Testing & Documentation

Gear pumps in this catalog are designed and acceptance-tested with reference to JB/T 6434 (external gear pumps), three-screw pumps to GB/T 10886, centrifugal chemical pumps to ISO 2858, and sealless or screw pumps to the relevant API 676 guidance, with mechanical seals supplied to API 682 configurations on request. Sanitary models are manufactured with surface finishes suitable for FDA / 3A style hygienic duties. Each shipment can include: performance test record against the quoted duty point, hydrostatic test certificate, material certificates for pressure-retaining parts, operating and maintenance manual, and a dimensional drawing with flange table. Tell us which standards your project specification cites and we will align the documentation pack accordingly.

🔧 Spare Parts & After-Sales Support

Every pump model page doubles as a spare-parts reference: rotor and gear sets, bearing and thrust assemblies, complete seal cartridges, relief valve kits and jacket gasket sets are manufactured in-house to the same drawings as the original build - so spares ordered years later still match. Recommended commissioning spares are one seal set and one gasket set per pump; for critical continuous-duty installations we recommend a full rotor set held on site. When ordering spares, quote the pump serial number and nameplate data so the correct material and clearance class is supplied. Technical support in English is available by email during China business hours, with video call diagnostics available for installation and commissioning issues.

ℹ️ Technical data on this page is sourced from the manufacturer's engineering database and applicable standards (JB/T 6434, GB/T 10886, ISO 2858, API 676). Final selection must be confirmed by our engineers against your actual duty conditions.

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