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VG21 Double Gear Pump

The VG21 is a fixed‑displacement internal meshing tandem (double) gear pump, combining a VG2 (front, larger displacement: 80–160 cc/r) and a VG1 (rear, smaller displacement: 25–63 cc/r) in one housing, sharing a common drive shaft. It features one common inlet and two independent outlets for dual‑circuit hydraulic systems. With axial & radial pressure compensation, it delivers high pressure (up to 31.5 MPa), low noise, low pulsation, and wide speed range (50–3000 rpm). Compact and versatile, it’s widely used in injection molding, die‑casting, and industrial machinery.

Model:
VG21
Brand:
Green Hydraulic
Model Number:
VG21
Packaging Details:
Standard export carton/plywood case
Testing Before Shipment:
Yes
Cartification:
ISO9001，CE
Markets:
• Industrial • Energy • Government (Non Aerospace) • HVAC • Mobile • Natural Resources • Transportation (Non Aerospace)
Application:
1. Industrial Hydraulic Systems 2. Mobile Equipment (Industrial Vehicles) 3. Construction and Engineering Machinery 4. Metallurgy Industry
Shaft Type:
Key Shaft and Spline shaft
MOQ:
1 set


Availability:



Inquiry

Product Description

VG21 Gear Pump Overview

The VG21 is a high-performance, fixed-displacement internal meshing tandem gear pump engineered for compact, dual-circuit hydraulic systems that demand reliable, high-pressure output and efficient operation. Featuring a rugged cast iron construction and integrated dual-stage design, the VG21 is specifically designed to deliver two independent flow rates from a single drive, making it an ideal choice for injection molding machines, die-casting equipment, and industrial machinery where space efficiency and multi-function performance are critical.

VG21

Features and Benefits

Rugged Cast Iron Construction:
The VG21 is built with heavy-duty cast iron bodies and covers, providing superior structural rigidity compared to lighter alternatives. This robust construction minimizes internal deflection and mechanical fatigue under continuous high-pressure duty cycles, ensuring stable performance and extended service life in demanding industrial environments.
High-Efficiency Internal Meshing Gear Design:
Utilizing precision-machined internal gear pairs, the VG21 offers inherently smoother operation and lower noise than external gear pump designs. This configuration delivers high volumetric efficiency while maintaining consistent performance even under varying load conditions.
Integrated Tandem (Dual-Stage) Configuration:
Combining a larger primary stage (VG2) and a smaller secondary stage (VG1) within a single housing, the VG21 provides two independent outlet flows from one common drive shaft. This allows for versatile dual-circuit operation, supporting both high-flow/low-pressure and low-flow/high-pressure functions simultaneously.
Advanced Pressure Compensation Technology:
Equipped with pressure-balanced components and axial compensation, the VG21 automatically optimizes internal clearances under pressure. This minimizes internal fluid bypass and friction, ensuring high mechanical efficiency and consistent power delivery across a wide range of operating pressures and temperatures.
Superior High-Pressure Capability:
Engineered to handle continuous operating pressures up to 31.5 MPa (4,568 psi), the VG21 features high-strength alloy gears and precision-machined components. This robust design allows it to power high-force actuators and complex hydraulic circuits with smooth, reliable flow.
Modular Versatility and Installation Flexibility:
The VG21 series offers a versatile range of combined displacements (from 25 to 160 cc/rev, depending on stage combinations) and supports standard mounting configurations. With a common inlet and dual independent outlets, it provides unmatched installation flexibility for compact machinery and multi-function hydraulic systems.

Specifications

Model Codes

Technical Data

Parameter	Specification
Pump Type	Fixed-displacement tandem internal meshing gear pump (VG2 + VG1 combination)
Displacement Range	• VG2 Stage: 80–160 cc/rev
Displacement Range	• VG1 Stage: 25–63 cc/rev
Continuous Pressure	Up to 31.5 MPa (4,568 psi)
Peak/Intermittent Pressure	Up to 35 MPa (5,076 psi)
Rated Speed Range	500–2,500 rpm (continuous)
Rated Speed Range	Max intermittent speed: 3,000 rpm
Minimum Operating Speed	50 rpm (with proper lubrication; recommended 500 rpm for continuous duty)
Efficiency	Volumetric efficiency: ≥92%
Efficiency	Mechanical efficiency: ≥90%
Fluid Compatibility	Premium mineral-based hydraulic fluids with AW additives
Viscosity Range	Optimal: 20–40 cSt
Viscosity Range	Operating: 10–430 cSt (cold start)
Filtration Requirement	ISO 4406 cleanliness level: 18/16/13 minimum
Operating Temperature	-20°C to +80°C (-4°F to +176°F)
Mounting Configurations	Standard SAE flanges (custom options available)
Port Configuration	Common suction port + two independent pressure ports (side/rear mounting options)
Shaft Type	Standard spline/keyed shafts (custom spline counts available)
Body Material	High-strength cast iron housing and covers
Gear Material	Hardened alloy steel gears
Seal Material	NBR (standard); FKM/Viton (high-temperature option)

VG21 Hydraulic Gear Pump Installation Dimensions

Applications

Applications

The VG21 series provides a rugged, high-efficiency power solution specifically tailored for industrial and mobile hydraulic systems where dual-circuit operation, high pressure, and reliable performance are essential:

Injection Molding & Die-Casting Machinery:
A primary choice for plastic injection molding machines and die-casting equipment, where the tandem design delivers independent high-flow/low-pressure and low-flow/high-pressure circuits for fast cycle times and precise mold clamping.
Industrial Hydraulic Power Units:
Widely used in compact hydraulic power packs for machine tools, presses, and automation systems, offering two independent pressure/flow outputs from a single drive to power multiple actuators simultaneously.
Material Handling Equipment:
Ideal for forklifts, stackers, and conveyor systems, where the dual-stage configuration supports both rapid traverse (high flow) and lifting/holding (high pressure) functions without needing separate pumps.
Mobile Construction Machinery:
Frequently employed in small excavators, skid-steer loaders, and aerial work platforms, providing space-efficient dual-circuit power for both primary working hydraulics and auxiliary functions like steering or stabilizers.
Agricultural Processing Equipment:
Used in combine harvesters, balers, and farm machinery, where the pump handles both high-cycle hydraulic operations (e.g., lifting, compaction) and auxiliary systems while resisting contamination in harsh field environments.
Specialized Industrial Presses:
Optimized for compact hydraulic presses and assembly machines, delivering the combination of fast advance (high flow) and high-pressure pressing (low flow) that tandem gear pumps excel at.

Vane Pump Application

Factory&FAQ

Packaging & Delivery

VG21 pumps are typically packaged securely to prevent damage during transit. The packaging includes:

Protective Wrapping: To safeguard the pump from environmental damage.

Custom Crates: For larger, heavier pumps, ensuring safe handling.

Documentation: Includes installation, maintenance instructions, and warranty details.

Delivery time depends on the model, customizations, and location but typically ranges from 2 to 6 weeks from the order date.

VG21 Gear Pump FAQ:

1. What are VG21 series gear pumps?

The VG21 is a high-performance, fixed-displacement internal meshing tandem gear pump. It combines two stages (VG2 primary + VG1 secondary) into a single, compact housing with a common drive shaft, engineered for dual-circuit hydraulic systems requiring reliable high-pressure output and efficient multi-function operation.

2. What makes the VG21 different from standard single gear pumps?

The VG21 is purpose-built for dual-circuit efficiency where single-stage pumps require separate units:

Integrated Tandem Design: Delivers two independent flow rates from one drive shaft, reducing installation space and cost compared to using two separate pumps.
High-Efficiency Internal Gear Design: Offers smoother operation, lower noise, and higher volumetric efficiency than external gear pumps, even under high pressure.
Dual-Circuit Flexibility: Supports simultaneous high-flow/low-pressure and low-flow/high-pressure functions (e.g., fast traverse + high-force clamping) in one compact package.

3. What is the working pressure range of VG21 pumps?

The VG21 is a high-pressure industrial specialist. Depending on the stage combination, the series typically handles:

Continuous Pressure: Up to 31.5 MPa (4,568 PSI).
Intermittent/Peak Pressure: Up to 35 MPa (5,076 PSI).

This robust pressure rating makes the VG21 ideal for powering injection molding, die-casting, and high-force industrial hydraulic circuits.

4. Can VG21 pumps replace other brands?

Yes, the VG21 is a high-quality alternative to other premium tandem internal gear pumps. It is often used as a replacement or upgrade for:

Nachi VDR Series
Rexroth 1PF2G Series
Yuken PV2R Tandem Pumps

To ensure a successful swap, verify the Mounting Flange, Shaft Type, and Displacement (both primary and secondary stage) to match your existing system.

5. What hydraulic oil is suitable for VG21 gear pumps？

To protect the precision internal gear set and pressure-balanced components, the following is recommended:

Oil Type: Premium mineral-based hydraulic fluids with strong Anti-Wear (AW) and anti-foam additive packages.
Viscosity: Standard ISO VG32 to VG68. The optimal operating range is 20–40 cSt, though it can handle cold starts up to 430 cSt.
Filtration: Cleanliness is vital for gear and bearing protection. A minimum filtration of ISO 4406 18/16/13 is recommended to prevent abrasive particles from damaging internal surfaces.

6. What is the typical speed range of VG21 pumps?

To protect the precision internal gear set and pressure-balanced components, the following is recommended:

Oil Type: Premium mineral-based hydraulic fluids with strong Anti-Wear (AW) and anti-foam additive packages.
Viscosity: Standard ISO VG32 to VG68. The optimal operating range is 20–40 cSt, though it can handle cold starts up to 430 cSt.
Filtration: Cleanliness is vital for gear and bearing protection. A minimum filtration of ISO 4406 18/16/13 is recommended to prevent abrasive particles from damaging internal surfaces.

7. Do you provide OEM or customized services?

Yes, we support OEM and customization, including nameplate, packaging, and specific performance requirements. Send us your drawings or specifications for evaluation.

8. How can I get a quotation quickly

Please provide the following details:

Model or displacement
Working pressure
Speed
Quantity
We will reply within 12 hours with a competitive quotation.

Certifications & Quality Assurance

VG21 pumps are manufactured in compliance with international standards, ensuring high performance and reliability:

ISO 9001: Certified for quality management systems.

CE Certification: Ensures compliance with European safety, health, and environmental protection standards.

RoHS Compliance: Ensures the pump does not contain hazardous materials.

Factory Testing: Every pump is rigorously tested for performance, pressure, and leak integrity before shipping.

FAQ

1.What's our advantages?

Factory established in 2005;

With a great deal of production experience;

80+ employees become the professional team;

Constant updated ERP system ensure efficiency of work;

Sophisticated equipment ehanced the accuracy of products;

Professional salesmen provide the greast service;

With a large number of famous customers all over the world;

Great after-sales service;

With the long term cooperation with famous logistics and express company in China,provide the better goods service.

2.What is your payment terms?

Small order/sample order,full payment in advance; Big orders send the first payment 30% before the production,and the balance before shippment.We'll show the photos of the products and packages before delivery.

3.Can you make my own brand on the products?

Of course we can. Just send me your logo we can make it for you.

4.What is our main export market?

America(40.5%):USA, Canada, Argentina, Brazil

Europe(30.8%):Italy,Germany,England,Holland,Spain,Swiss,Finland,Russia,Poland.

Asia(23.5%):Korea,singapore,India,Turkey,Vietnam,Saudi Arabia,Syria, Israel,Lebanon.

Others(5.8%).

Unedited footage of the Green Hydraulic Factory

The Green hydraulic pump manufacturing facility is a specialized industrial plant that focuses on producing hydraulic pumps and related components. These factories are equipped with advanced machinery and technology to fabricate high-quality pumps designed for a wide range of applications, from heavy equipment and machinery to automotive and industrial systems.

The production process typically involves precision engineering, where raw materials like metals and alloys are processed into pump components such as gears, pistons, cylinders, and seals. These parts are then assembled into fully functional hydraulic pumps, which are tested for performance and quality control to ensure reliability, efficiency, and durability under various working conditions.

Green Hydraulic's manufacturing facilities for hydraulic pumps maintain stringent quality standards, often adhering to international certifications, to meet the expectations of customers in industries such as construction, agriculture, automotive, and manufacturing.

Unedited footage of the Green Hydraulic Factory3

All hydraulic pumps produced by Green Hydraulic have undergone compliance testing, ensuring their quality and reliability.

Unedited footage of the Green Hydraulic Factory4

To meet the diverse needs of different industries, the green hydraulic offer customization options, such as specialized seals, materials, and pump configurations. These facilities often work closely with engineering teams to develop tailored solutions for specific applications, from high-pressure systems to low-flow, high-efficiency pumps.

Unedited footage of the Green Hydraulic Factory5

Each pump undergoes a rigorous quality control process, where pressure tests and performance assessments are conducted to ensure that the pumps meet the required standards for flow rate, pressure capacity, and durability.