GNB High-Viscosity Internal Gear Pump (GNB Series)
High-Viscosity Internal Gear Pumps•GNB
- Flow Range
- 2 ~ 60 m³/h
- Pressure Range
- 0.6 ~ 1.2 MPa
- Motor Power
- 3 ~ 55 kW
- Model
- GNB-2 → GNB-60
- Customs HS Code
- 8413.60.29
Hydraulic Principle & Internal Construction
The GNB heavy-duty internal meshing pump is built for extreme operating conditions including high temperature, crystallization-prone polymers, and high-differential pressure circuits. Featuring an integrated full-envelope heating jacket for steam or hot oil circulation, it prevents media solidification and maintains pump fluidity during startup.
Model-by-Model Technical Specifications
| Model | Inlet | Outlet | Flow (m³/h) | Pressure (MPa) | Speed (rpm) | Motor (kW) |
|---|---|---|---|---|---|---|
| GNB-2 | DN40 | DN40 | 2 | 0.6 | 250 | 3 |
| GNB-5 | DN50 | DN50 | 5 | 0.8 | 380 | 5.5 |
| GNB-10 | DN65 | DN65 | 10 | 0.8 | 450 | 7.5 |
| GNB-20 | DN80 | DN80 | 20 | 1 | 550 | 15 |
| GNB-30 | DN100 | DN100 | 30 | 1.2 | 650 | 30 |
| GNB-60 | DN150 | DN150 | 60 | 1.2 | 750 | 55 |
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 GNB series 1-page technical datasheet covering all 6 model configurations.
Media Compatibility & Viscosity / Temperature Guide
| Medium | Max Viscosity (cSt) | Application Note |
|---|---|---|
| Waterproofing Membrane Bitumen Compound | 200,000 | ≤260°C |
| Kraft Pulping Black Liquor Lignin | 150,000 | Corrosion-Resistant Configuration |
| Textile Printing Pastes & Size | 120,000 | Chemical Processing |
| Polyester Resin / Liquid Silicone Rubber Base | 180,000 | Polymeric Construction Adhesives |
International Benchmark & Interchange Guide
International Benchmarks
- Viking Pump internal gear series
- IMO internal gear pumps
Interchange Note
Heavy-duty internal gear pump with heating jacket. Interchangeable with Viking heavy-duty 124A/224A series and Gorman-Rupp internal gear pumps.
Materials & Shaft Seal Selection Guide
Engineering metallurgy and seal selection advice for corrosiveness and temperature: For transferring asphalt, hot-melt adhesives, or viscous media with particles/corrosivity, prefer ductile iron (HT250+) for pump bodies to enhance wear resistance; use 316L stainless steel for contact surfaces. For seals, double mechanical seals with flushing liquid are recommended for standard conditions; bellows seals are preferred for high temperature or strong corrosion. Packing glands suit low-pressure, non-wear fluids but require regular adjustment. All seal materials must withstand media temperature and chemical properties to avoid swelling or hardening failure.
- Casing & Housing Materials
- High-Strength Ductile Iron (GGG50 / QT500)AISI 316 Stainless Steel
- Rotor / Gear / Screw Elements
- Wear-Resistant Hardened Alloy Steel Gear Set
- Shaft Sealing Options
- Cartridge Mechanical SealPTFE / Graphite Composite Packing Seal
Engineering FAQ
To ensure smooth suction of high-viscosity media, the suction inlet pipe diameter should be as large as possible (typically not smaller than the outlet) with a trumpet-shaped design. At least 3-5 pipe diameters of straight run must be maintained before the inlet to stabilize flow; valves or elbows are strictly prohibited at the suction inlet. Installation height must be strictly controlled to ensure NPSHa exceeds NPSHr, preventing cavitation caused by high viscosity.
📐 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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