Gear pump
Tandem Hydraulic Gear Pump 1PDF+1PDF
Hengyuhang Tandem Hydraulic Gear Pump 1PDF+1PDF Series is a high-performance dual-stage external gear pump pairing two Group 1 sections to deliver independent dual-circuit fluid power with high volumetric efficiency and working pressure up to 300 bar.
| Applications of Hengyuhang Tandem Hydraulic Gear Pump 1PDF+1PDF Series
This tandem gear pump series is engineered for multi-function mobile machinery and industrial compact systems requiring two isolated hydraulic circuits driven from a single prime mover. Typical applications include micro and mini excavators, compact garden tractors, municipal maintenance sweepers, material handling stackers, scissor lift platforms, and dual-function electro-hydraulic power units requiring separate implement actuation, steering priority, or hydraulic cooling circuits.
| Key Technical Specifications
Product Model: Hengyuhang Tandem Hydraulic Gear Pump 1PDF+1PDF Series
Brand Replacement: Marzocchi, Danfoss, Rexroth, Parker OEM or as requested.
Displacement: 1.4+1.4 to 13.8+13.8 cm³/rev (Stage 1 + Stage 2)
Rotation Direction: Clockwise (D), counter-clockwise (S)
Speed Range: Min. speed 600 to 800 r/min; Max. speed 3500 to 4000 r/min
Peak Pressure: 210 to 300 bar (3,045 to 4,350 psi)
- Description
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| Overview of HENGYUHANG Tandem Hydraulic Gear Pump 1PDF+1PDF Series
The HENGYUHANG 1PDF+1PDF Series is a precision double external gear pump assembly uniting two Group 1 (1PDF) standard hydraulic displacement sections via a heavy-duty internal through-shaft and hardened splined coupling. Spanning a broadened Group 1 displacement range from 1.4+1.4 cm³/rev up to 13.8+13.8 cm³/rev, this dual-stage architecture supplies two completely independent hydraulic circuits from a single engine PTO or electric motor. The tandem integration eliminates duplicate drive motors, heavy split gearboxes, and problematic flow-divider throttling circuits, substantially reducing equipment chassis space, installation labor, and overall hydraulic system weight.
Constructed with high-strength extruded aluminum alloy bodies, hardened one-piece integral gear-and-shaft assemblies, and hydrostatic pressure-balanced DU composite bushing plates, the 1PDF+1PDF series sustains exceptional volumetric and mechanical efficiencies above 94%. Both primary (P1) and secondary (P2) stages operate at rated continuous pressures up to 250 bar (3,625 psi) and peak spike pressures up to 300 bar (4,350 psi). Offered with separate suction ports or an integrated common suction port for simplified plumbing, the series incorporates standardized European 4-bolt rectangular flanges (pilot Ø 25.4 mm), European diamond flanges (pilot Ø 30.0 mm), and SAE "AA" 2-bolt flanges, providing seamless 1:1 drop-in interchangeability across 27 global hydraulic brands.
| Dimension of HENGYUHANG Tandem Hydraulic Gear Pump 1PDF+1PDF Series
Interface data needed with the drawing:
| Item | Value |
|---|---|
| Primary mounting flange options (Stage 1 Front) | 1. European standard 4-bolt rectangular flange (pilot Ø 25.4 -0.02/-0.05 mm with 52.4 × 71.8 mm bolt pitch, 4-M6 or 4-M8 bolt holes) / 2. European standard 2-bolt diamond/rhomboid flange (pilot Ø 30.0 mm with 73.0 mm bolt centers) / 3. SAE "AA" 2-bolt oval mounting flange (pilot Ø 50.8 mm with 82.5 mm bolt centers) |
| Primary drive shaft options | 1. European 1:8 tapered shaft with woodruff key (M10×1.0 nut, key width 2.4 mm or 3.0 mm) / 2. Cylindrical keyed shaft: Ø 12.0 mm or Ø 12.7 mm (1/2 in) with flat key / 3. Involute splined shaft: DIN 5482 B12×9 or SAE 9T / 11T involute spline |
| Intermediate coupling | Heavy-duty internal splined sleeve connecting primary output shaft to secondary input shaft; rated for full tandem torque transmission. |
| Suction port options (Inlet) | 1. Separate suction: independent inlet ports for Stage 1 and Stage 2 / 2. Common suction: enlarged single suction port on Stage 1 supplying both pump chambers, minimizing suction hose routing |
| Port configurations | 1. European standard diamond 4-bolt flanged ports (M6 threads) / 2. BSPP parallel threaded ports (G 3/8, G 1/2) / 3. SAE straight thread O-ring boss ports (UNF/UN threads) |
| Rotation | Clockwise (R / D) or Counter-clockwise (L / S), viewed looking directly at the primary drive shaft. |
| Body construction | High-tensile extruded aluminum alloy body with heavy-duty cast iron or aluminum front mounting flange and intermediate/rear adapter covers. |
| Shaft loading limits | Pure torsional torque transmission required via flexible elastic coupling; zero external axial or radial loads permitted on the primary shaft. |
| Fastener torque limits | Front flange mounting bolts: 25 ±2 Nm; Tie-rod body assembly bolts: 30 ±3 Nm; Port flange screws (M6): 10 ±1 Nm. |
| Pump Installation Specifications HENGYUHANG 1PDF+1PDF Series
The HENGYUHANG 1PDF+1PDF Series pump utilizes a standardized modular ordering code structure:
Code structure — reference: 1PDF+1PDF — Tandem Hydraulic External Gear Pump Series
| Segment | Meaning | Standard Options & Features |
|---|---|---|
| Series | 1PDF+1PDF | Dual-stage Group 1 + Group 1 tandem external gear pump assembly |
| Displacement P1 | 1.4 to 13.8 | Primary stage: 1.4, 2.1, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev |
| Displacement P2 | 1.4 to 13.8 | Secondary stage: 1.4, 2.1, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev |
| Rotation | D / S | D: Clockwise (viewed from drive shaft end); S: Counter-clockwise |
| Drive Shaft | T1 / C1 / S1 | T1: European 1:8 tapered shaft; C1: Cylindrical keyed shaft; S1: Involute splined shaft |
| Mounting Flange | F1 / F2 / F3 | F1: European 4-bolt rectangular (Ø 25.4 mm); F2: European diamond (Ø 30 mm); F3: SAE AA |
| Suction Config | S / C | S: Separate inlets for P1 and P2; C: Common suction port for shared reservoir line |
| Ports | F / B / U | F: European diamond 4-bolt flanged ports; B: BSPP threaded ports; U: SAE O-ring boss ports |
| Seals | N / V | N: Standard NBR (-20 °C to +80 °C); V: FKM / Viton (-10 °C to +150 °C) |
| Reading your replacement code
| Your Target Brand & Series | HENGYUHANG Equivalent | Interchange Verification Notes |
|---|---|---|
| MARZOCCHI GHP2A, ALP2A, GHP2, ALP2, 1PD Series | HENGYUHANG 1PDF+1PDF Series | 100% 1:1 drop-in replacement; identical Group 1 flange pilots, shaft extensions, port spacing, and tandem intermediate drive |
| DANFOSS SNP1NN, SNP2NN, SNW2NN Series | HENGYUHANG 1PDF+1PDF Series | Direct form, fit, and functional replacement; matching displacement combinations and continuous 250 bar pressure ratings |
| HYDAC PGE102, PGE104 Series | HENGYUHANG 1PDF+1PDF Series | Fully interchangeable mounting pilot, bolt circles, shaft splines, and tandem through-drive coupling |
| ARGO-HYTOS GP1, GP2, GP3 Series | HENGYUHANG 1PDF+1PDF Series | Exact match across nominal displacements, flange patterns, and pressure capabilities |
| ATOS PFG Series | HENGYUHANG 1PDF+1PDF Series | Plug-and-play installation; matching European 4-bolt/diamond flange and 1:8 tapered shaft options |
| Brevini OT100, OT200, OT300 Series | HENGYUHANG 1PDF+1PDF Series | Direct replacement for multi-function mobile auxiliary and work hydraulic systems |
| BUCHER AP100, AP200, AP212, AP300 Series | HENGYUHANG 1PDF+1PDF Series | High volumetric efficiency, low noise output, and identical mechanical port centerlines |
| BONDIOLI & PAVESI HPLPA1, HPLPA2, HPLPA3 Series | HENGYUHANG 1PDF+1PDF Series | Direct agricultural and industrial tractor drop-in tandem replacement |
| Boden BAP1, BHP1, BAP2, BHP2, BAP3, BHP3 Series | HENGYUHANG 1PDF+1PDF Series | Exact displacement matching, port dimensions, and continuous 250 bar pressure ratings |
| Caproni 10A, 20A, 30A, 10C, 20C, 30C Series | HENGYUHANG 1PDF+1PDF Series | Full mechanical interchangeability; matching shaft keys, flange pilots, and body lengths |
| CASAPPA PLP10, PLP20, PLP30 (Polaris) Series | HENGYUHANG 1PDF+1PDF Series | 100% drop-in tandem replacement for PLP10/10 double pump configurations |
| CONCENTRIC WP300, WP900, WP1500 Series | HENGYUHANG 1PDF+1PDF Series | Equivalent flow delivery, mounting dimensions, and high-speed operation up to 4000 rpm |
| DUPLOMATIC 1P, GP1, GP2, GP3 Series | HENGYUHANG 1PDF+1PDF Series | Direct industrial power unit and machine tool tandem replacement |
| Galtech 1SPA, 2SPA, 3GPG, 3SPA Series | HENGYUHANG 1PDF+1PDF Series | Exact match on mounting flange, shaft tapers, and flanged port pitch |
| GRH 1PF, 2PF, 3PF Series | HENGYUHANG 1PDF+1PDF Series | Direct drop-in match across all Group 1 + Group 1 displacement combinations |
| HANSA-TMP 1SP, 2SP, 3GPG, 3SPA Series | HENGYUHANG 1PDF+1PDF Series | 100% interchangeable fluid power parameters and compact axial body length |
| HESPER HA11, HA2, HA3, CHP1 Series | HENGYUHANG 1PDF+1PDF Series | Direct replacement for mobile work circuits and steering priority systems |
| HONOR 1KH Series | HENGYUHANG 1PDF+1PDF Series | Drop-in dimensional envelope and identical hydraulic port positions |
| HPI P1BAN1, P1BAN2, P1AAN2, P1BAN3, P1AAN3 Series | HENGYUHANG 1PDF+1PDF Series | Exact replacement for French/European mobile machinery standards |
| HYDRONIT E Series | HENGYUHANG 1PDF+1PDF Series | Perfect fit for dual-function electro-hydraulic power packs and compact work circuits |
| JIHOSTROJ P23, J, T3, Q2, UD Series | HENGYUHANG 1PDF+1PDF Series | Exact drop-in replacement for Czech/Central European machinery |
| PARKER PGP505, PGP502, PGP511, PGP517 Series | HENGYUHANG 1PDF+1PDF Series | Direct replacement for Parker Group 1 + Group 1 tandem gear pumps |
| Rexroth AZPB, AZPF, AZPG, AZPN Series | HENGYUHANG 1PDF+1PDF Series | 100% compatible drop-in replacement for Rexroth double gear pumps |
| RONZIO 01ZAG, 01ZBG, 02ZAG, 02ZCG, 02ZLG Series | HENGYUHANG 1PDF+1PDF Series | Exact match on aluminum body geometry, flange pilots, and shaft splines |
| ROQUET 1L0, PLA, GZ, G, GLA, PLC Series | HENGYUHANG 1PDF+1PDF Series | Direct drop-in replacement for Spanish and international agricultural equipment |
| SDH CBD Series | HENGYUHANG 1PDF+1PDF Series | Equivalent pressure levels, displacement sizes, and mounting dimensions |
| VIVOLO X1P, XV-1P, X2P, X3P, XV-2P, XV-3P Series | HENGYUHANG 1PDF+1PDF Series | Direct replacement for Vivoil Group 1 + Group 1 single and tandem external gear pumps |
Techspecs — HENGYUHANG 1PDF+1PDF Series
Displacement Performance Matrix (Per Stage)
| Displacement Size (cm³/rev) | Rated Continuous Pressure p1 (bar) | Intermittent Pressure p2 (bar) | Maximum Peak Pressure p3 (bar) | Max. Speed (r/min) | Min. Speed (r/min) | Flow Rate per Stage @ 1500 r/min (l/min) | Flow Rate per Stage @ 3000 r/min (l/min) |
|---|---|---|---|---|---|---|---|
| 1.4 | 250 | 275 | 300 | 4,000 | 800 | 2.10 | 4.20 |
| 2.1 | 250 | 275 | 300 | 4,000 | 800 | 3.15 | 6.30 |
| 2.8 | 250 | 275 | 300 | 4,000 | 800 | 4.20 | 8.40 |
| 3.5 | 250 | 275 | 300 | 4,000 | 700 | 5.25 | 10.50 |
| 4.1 | 250 | 275 | 300 | 4,000 | 700 | 6.15 | 12.30 |
| 5.2 | 250 | 275 | 300 | 3,800 | 700 | 7.80 | 15.60 |
| 6.2 | 230 | 255 | 280 | 3,500 | 600 | 9.30 | 18.60 |
| 7.6 | 210 | 235 | 260 | 3,500 | 600 | 11.40 | 22.80 |
| 9.3 | 190 | 215 | 240 | 3,000 | 600 | 13.95 | 27.90 |
| 11.0 | 170 | 195 | 220 | 2,800 | 600 | 16.50 | 33.00 |
| 13.8 | 160 | 180 | 200 | 2,500 | 600 | 20.70 | 41.40 |
| Note: Any displacement size from 1.4 to 13.8 cm³/rev can be combined in primary (P1) and secondary (P2) stages (e.g., 1PDF-3.5+1PDF-3.5, 1PDF-6.2+1PDF-2.1, 1PDF-11.0+1PDF-4.1). Total transmitted drive torque must remain within maximum drive shaft and intermediate coupling limits. | |||||||
Operating Conditions & Fluid Specifications
| Parameter | Specification | Operating Range & Criteria |
|---|---|---|
| Hydraulic fluid | Mineral hydraulic oil | Mineral-based anti-wear hydraulic oil conforming to DIN 51524 part 2 (HLP) or part 3 (HVLP) |
| Operating fluid temperature | Standard range | -20 °C to +80 °C with NBR seals; -10 °C to +110 °C with optional FKM / Viton seals |
| Operating viscosity | Recommended range | ν = 20 to 80 mm²/s (cSt); Permissible operating range: ν = 10 to 1,000 mm²/s |
| Cold start viscosity limit | Maximum viscosity | ν_max ≤ 1,500 mm²/s at p ≤ 10 bar and speed ≤ 1,500 r/min |
| Suction port pressure | Inlet pressure range | p_inlet = 0.7 to 2.5 bar absolute (0.07 to 0.25 MPa absolute) to prevent suction cavitation |
| Fluid cleanliness level | Maximum contamination | Class 20/18/15 according to ISO 4406 or Class 9 according to NAS 1638 |
| Recommended filtration | Filter rating | Return line filtration β10 ≥ 75 or pressure filtration β25 ≥ 100 |
Advantages — HENGYUHANG 1PDF+1PDF Series
Expanded Group 1 Displacement Range (Up to 13.8+13.8 cm³/rev)
Offers broader flow capacity than standard mini pumps, delivering up to 41.4 l/min per stage at 3,000 rpm while preserving the compact Group 1 mounting envelope.
Dual Independent Circuit Control
Powers two completely isolated hydraulic circuits from a single power source, perfectly separating work hydraulics from steering, fan drive, or pilot circuits.
High Volumetric Efficiency (>94%)
Precision-machined gear profiles and hydrostatic pressure-balanced wear plates guarantee minimal internal slip across high operating temperatures and cyclic pressures.
Compact Space & Weight Reduction
Eliminates the bulk, cost, and complexity of twin electric motors, secondary bell housings, or mechanical splitter gearboxes.
Common or Separate Suction Routing
Available with a unified inlet port on the primary section feeding both stages to minimize hydraulic reservoir hose connections, or separate inlets for dedicated reservoirs.
Low Noise & Low Pulsation
High-precision hobbed gear teeth and optimized internal decompression relief grooves ensure smooth, whisper-quiet operation across all speed ranges.
Reference — HENGYUHANG 1PDF+1PDF Series
Series Architecture
The HENGYUHANG 1PDF+1PDF Series provides modular flexibility across 11 displacement sizes:
Stage 1 (1PDF Group 1): 1.4, 2.1, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev
Stage 2 (1PDF Group 1): 1.4, 2.1, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev
Common Popular Combinations: 1PDF-2.1+1PDF-2.1, 1PDF-3.5+1PDF-3.5, 1PDF-4.1+1PDF-2.1, 1PDF-6.2+1PDF-3.5, 1PDF-7.6+1PDF-4.1, 1PDF-11.0+1PDF-5.2, 1PDF-13.8+1PDF-6.2
Target Brand Interchangeability Matrix
The HENGYUHANG 1PDF+1PDF Series is engineered to provide verified 1:1 drop-in replacement across 27 leading international hydraulic brands:
MARZOCCHI: GHP2A, ALP2A, GHP2, ALP2, 1PD Series (Double pump combinations)
DANFOSS: SNP1NN, SNP2NN, SNW2NN Tandem Series
HYDAC: PGE102, PGE104 Series
ARGO-HYTOS: GP1, GP2, GP3 Double Gear Pump Series
ATOS: PFG Series Double Pumps
Brevini: OT100, OT200, OT300 Series Tandem Gear Pumps
BUCHER: AP100, AP200, AP212, AP300 Series Double Pumps
BONDIOLI & PAVESI: HPLPA1, HPLPA2, HPLPA3 Tandem Series
Boden: BAP1, BHP1, BAP2, BHP2, BAP3, BHP3 Series
Caproni: 10A, 20A, 30A, 10C, 20C, 30C Series
CASAPPA: PLP10, PLP20, PLP30 (Polaris PLP10/10) Series
CONCENTRIC: WP300, WP900, WP1500 Series
DUPLOMATIC: 1P, GP1, GP2, GP3 Series Tandem
Galtech: 1SPA, 2SPA, 3GPG, 3SPA Series
GRH: 1PF, 2PF, 3PF Series Double Pumps
HANSA-TMP: 1SP, 2SP, 3GPG, 3SPA Series
HESPER: HA11, HA2, HA3, CHP1 Series
HONOR: 1KH Series
HPI: P1BAN1, P1BAN2, P1AAN2, P1BAN3, P1AAN3 Series
HYDRONIT: E Series Mini Power Pack Pumps
JIHOSTROJ: P23, J, T3, Q2, UD Series
PARKER: PGP505, PGP502, PGP511, PGP517 Series
Rexroth: AZPB, AZPF, AZPG, AZPN Series Double Gear Pumps
RONZIO: 01ZAG, 01ZBG, 02ZAG, 02ZCG, 02ZLG Series
ROQUET: 1L0, PLA, GZ, G, GLA, PLC Series
SDH: CBD Series
VIVOLO: X1P, XV-1P, X2P, X3P, XV-2P, XV-3P Series
Brand Replacement
Quanzhou Hengyuhang Power Technology Co., Ltd. manufactures the 1PDF+1PDF Series conforming precisely to European and international SAE mounting standards. Every manufactured unit undergoes computerized end-of-line digital testing, verifying individual stage displacement, continuous rated pressure holding, inter-stage seal barrier isolation, and overall mechanical efficiency. Machine builders, hydraulic system integrators, and plant maintenance managers can directly replace OEM double pumps across all 27 specified brands (MARZOCCHI, DANFOSS, HYDAC, ARGO-HYTOS, ATOS, Brevini, BUCHER, BONDIOLI & PAVESI, Boden, Caproni, CASAPPA, CONCENTRIC, DUPLOMATIC, Galtech, GRH, HANSA-TMP, HESPER, HONOR, HPI, HYDRONIT, JIHOSTROJ, PARKER, Rexroth, RONZIO, ROQUET, SDH, VIVOLO) with zero modifications to drive bells, shaft couplings, or hydraulic line geometry.
Applications — HENGYUHANG 1PDF+1PDF Series
Mini Excavators & Compact Track Loaders: Independent supply for pilot joystick controls, swing drives, or auxiliary attachments.
Aerial Work Platforms & Scissor Lifts: Dual hydraulic circuit actuation for lift elevation and auxiliary steering/drive systems.
Agricultural Compact Tractors & Implements: Integrated steering priority circuits combined with hitch/implement lift hydraulics.
Municipal Road Sweepers & Turf Maintenance Equipment: Dual drive for broom rotation, water spray pump actuation, and steering.
Compact AC/DC Electro-Hydraulic Power Units: High-efficiency power packs for tail lifts, dock levelers, scissor tables, and vehicle hoists.
Package & Shipping
| Packaging | Individual shock-absorbing custom molded foam in heavy-duty export cartons; moisture-resistant VCI polybags; fumigation-free wooden export pallets for consolidated freight. |
|---|---|
| Selling Unit | Single item (MOQ: 1 piece for standard stock models; low MOQ for customized OEM tandem assemblies). |
| Single Package Size | 32.0 × 22.0 × 19.0 cm (12.60 × 8.66 × 7.48 in) per tandem pump. |
| Single Gross Weight | 3.20 to 5.20 kg (7.05 to 11.46 lbs) depending on displacement combinations. |
| Standard Lead Time | 3–5 business days for stock items; 12–15 business days for volume OEM batch customization. |
| Logistics & Express | Worldwide air express (DHL, FedEx, UPS, TNT), air cargo, maritime shipping (LCL / FCL), and multimodal door-to-door DDP services. |
| Customization Services | Custom laser nameplate marking, private branding, common or separate suction port routing, customized shaft splines, and special seal compounds. |
| Warranty & Support | 12 months comprehensive warranty from dispatch date; full lifetime technical support. |
Why Choose Hengyuhang?
Direct Factory Precision Manufacturing & CNC Excellence: Equipped with multi-axis CNC machining centers, automated high-speed gear hobbing, and ultra-fine micro-lapping equipment, Hengyuhang maintains sub-micron gear profile tolerances (Ra < 0.2 μm) and exact balance plate clearances. This guarantees minimal internal bypass leakage, virtually zero pressure pulsation, and repeatable performance across high-volume production batches.
100% Full-Cycle Multi-Parameter Factory Inspection: Every single hydraulic pump undergoes rigorous end-of-line digital testing before dispatch. Quality checks cover full continuous rated and peak pressure hold, internal bypass leakage verification, inter-stage seal barrier testing, high/low temperature volumetric efficiency testing (>92–94%), and acoustic noise spectrum profiling, ensuring zero-defect delivery.
Seamless 1:1 OEM Drop-In Interchangeability: Conforming precisely to international European standard, SAE, and DIN/ISO mounting configurations, our pumps deliver genuine plug-and-play replacement for MARZOCCHI, DANFOSS, Rexroth, PARKER, and 23 other leading global manufacturers. Machine operators can replace original units without modifying bell housings, drive couplings, or hydraulic line geometry.
Flexible Engineering Customization & Rapid Prototyping: Backed by an experienced in-house hydraulic engineering team, Hengyuhang offers comprehensive bespoke customization, including non-standard mounting flanges, special shaft tapers or splines, common or separate suction port routing, and integrated valve blocks. We support low-MOQ trial orders and agile custom prototyping to resolve obsolescence issues for high-end machinery.
Robust Supply Chain, Extensive Inventory & Fast Global Dispatch: With dedicated casting, extrusion, and precision machining facilities, raw material reserves, and extensive finished inventory across all Group 1 displacement models, standard orders ship within 48 to 72 hours. We partner strategically with major international logistics carriers to provide seamless door-to-door DDP global delivery.
12-Month Comprehensive Warranty & Lifetime Technical Support: All Hengyuhang hydraulic pumps are backed by a complete 12-month factory warranty and dedicated lifetime technical assistance. Our specialized fluid power engineers provide free 24-hour CAD drawing verification, OEM cross-reference confirmation, hydraulic displacement calculations, and system troubleshooting to ensure total operational peace of mind.
Tandem Hydraulic Gear Pump Group 1PDF+1PDF Series (1.4+1.4 to 13.8+13.8 cm³/rev) is a high-performance modular dual-stage external gear pump engineered to deliver dual independent hydraulic power streams or combined two-stage high-low flow from a single prime mover. By coupling two high-pressure Group 1PDF pump sections through an internal heavy-duty intermediate spline through-drive shaft, this tandem assembly provides flexible displacement pairings across 11 standard displacements from 1.4 up to 13.8 cm³/rev per section (total combined displacement up to 27.6 cm³/rev). Built with high-tensile extruded aircraft-grade aluminium alloy housings, case-hardened micro-finished alloy steel gear sets, and hydrostatic axial pressure-balanced composite DU bushings, the 1PDF+1PDF tandem series withstands continuous operating pressures up to 250 bar (25 MPa) and intermittent peak pressures up to 300 bar (30 MPa). Featuring standard European 4-bolt rectangular flanges (Ø25.4 mm or Ø30 mm pilot) or SAE "AA" 2-bolt oval flanges (Ø50.8 mm pilot), 1:8 European taper or cylindrical keyed drive shafts, and independent or common suction porting, this series maintains over 93% volumetric efficiency and provides a seamless 1:1 drop-in replacement for CASAPPA POLARIS (PLP10+PLP10), Bosch Rexroth (AZPF+AZPF / AZPB+AZPB), Marzocchi, Parker, and Danfoss dual Group 1 gear pumps.
| Applications
The 1PDF+1PDF tandem hydraulic gear pump series is specifically engineered for multi-function mobile machinery and compact industrial power packs requiring two simultaneous hydraulic circuits without adding secondary motors or gearboxes, including agricultural tractors (implement lift plus auxiliary steering/braking), electric and diesel counterbalance forklifts (main mast elevation plus power steering or hydraulic side-shift), mini and compact excavators, skid steer loaders, scissor lifts and aerial work platforms, dual-speed high-low hydraulic presses (rapid low-pressure cylinder advance and high-pressure clamping), truck-mounted tail lifts, dock levelers, road sweepers, and centralized industrial machine tool lubrication and clamping units.
| Key Specifications Overview
| Parameter | Specification |
|---|---|
| Series Architecture | Modular Dual-Stage External Hydraulic Gear Pump (Group 1PDF Front + Group 1PDF Rear) |
| Front Stage Displacement Range | 1.4 ~ 13.8 cm³/rev (11 standard sizes: 1.4, 2.0, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev) |
| Rear Stage Displacement Range | 1.4 ~ 13.8 cm³/rev (11 standard sizes: 1.4, 2.0, 2.8, 3.5, 4.1, 5.2, 6.2, 7.6, 9.3, 11.0, 13.8 cm³/rev) |
| Total Combined Displacement | 2.8 ~ 27.6 cm³/rev (fully modular independent displacement matching: V1 + V2) |
| Continuous Operating Pressure (P1) | 180 ~ 250 bar (250 bar for 1.4~4.1 cc; 240 bar for 5.2 cc; 230 bar for 6.2 cc; 220 bar for 7.6 cc; 200 bar for 9.3 cc; 190 bar for 11.0 cc; 180 bar for 13.8 cc) |
| Intermittent Operating Pressure (P2) | 200 ~ 275 bar (model dependent) |
| Max. Peak Pressure (P3) | 220 ~ 300 bar (model dependent) |
| Operational Speed Range | 600 ~ 4000 r/min (intermittent rating up to 6000 r/min for smaller displacement stages) |
| Volumetric Efficiency | ≥ 93% across recommended operating speed and temperature envelope |
| Hydro-Mechanical Efficiency | ≥ 89% ~ 91% |
| Housing Construction | High-tensile extruded aircraft-grade aluminium alloy body with ductile cast-iron or aluminium front/intermediate/rear covers |
| Mounting Flange Options | Standard European 4-bolt rectangular flange (pilot Ø25.4 mm or Ø30 mm) / SAE "AA" 2-bolt flange (pilot Ø50.8 mm, 82.55 mm pitch) / Italian 4-bolt flange |
| Drive Shaft Options | European 1:8 taper shaft with woodruff key (M10×1 / M12×1.25), Ø12.0 mm / Ø12.7 mm straight keyed shaft, or involute splined shaft |
| Intermediate Coupling Mechanism | Precision-hardened alloy steel internal spline through-drive coupling shaft connecting front and rear gear sets |
| Port Configuration Options | Independent suction & pressure ports (European 4-bolt diamond flange, BSPP G 3/8" / G 1/2", or SAE UNF); shared common suction inlet optional |
| Rotation Direction | Clockwise (D / Right-Hand) standard; Counter-Clockwise (S / Left-Hand) available upon request |
| Hydraulic Fluid Compatibility | Mineral oil-based hydraulic fluids (HL / HLP to ISO 6743/4; DIN 51524 Class 1 and 2); viscosity 12 ~ 100 mm²/s (cSt) |
| Operating Temperature Range | -20°C to +85°C (standard NBR elastomeric seals); -15°C to +110°C (optional Viton FKM seals) |
| Fluid Cleanliness Standard | ISO 4406 Class 20/18/15 (NAS 1638 Class 8~9) with return filtration β25 ≥ 75 |
| Individual Stage Performance & Parameter Ratings (Group 1PDF)
| Stage Model Code | Displacement (cm³/rev) | Operating Pressure (bar) | Rotational Speed (r/min) | Theor. Flow @ 1500 rpm (L/min) | |||
|---|---|---|---|---|---|---|---|
| P1 (Continuous) | P2 (Intermittent) | P3 (Peak) | Max. Speed | Min. Speed | |||
| 1PDF1.4 | 1.40 | 250 | 275 | 300 | 4000 | 600 | 2.10 |
| 1PDF2.0 | 2.00 | 250 | 275 | 300 | 4000 | 600 | 3.00 |
| 1PDF2.8 | 2.80 | 250 | 275 | 300 | 4000 | 600 | 4.20 |
| 1PDF3.5 | 3.50 | 250 | 275 | 300 | 4000 | 600 | 5.25 |
| 1PDF4.1 | 4.10 | 250 | 275 | 300 | 4000 | 600 | 6.15 |
| 1PDF5.2 | 5.20 | 240 | 260 | 280 | 3800 | 600 | 7.80 |
| 1PDF6.2 | 6.20 | 230 | 250 | 270 | 3600 | 600 | 9.30 |
| 1PDF7.6 | 7.60 | 220 | 240 | 260 | 3500 | 600 | 11.40 |
| 1PDF9.3 | 9.30 | 200 | 220 | 240 | 3500 | 600 | 13.95 |
| 1PDF11.0 | 11.00 | 190 | 210 | 230 | 3000 | 600 | 16.50 |
| 1PDF13.8 | 13.80 | 180 | 200 | 220 | 3000 | 600 | 20.70 |
| Tandem Combination Principles & Mechanical Drive Guidelines
| Engineering Factor | Design Specification & Application Recommendation |
|---|---|
| Displacement Hierarchy Rule | To optimize shaft torque transmission and structural stability, the stage with the larger displacement should ideally serve as the front pump (P1) and the equal or smaller displacement stage as the rear pump (P2): V1 ≥ V2. |
| Total Drive Shaft Input Torque | The primary drive shaft transfers the sum of torque required by both stages: T_total = T1 (front) + T2 (rear) ≤ T_max allowable for the front drive shaft (1:8 taper shaft: max 45 Nm; Ø12.7 mm keyed shaft: max 35 Nm). |
| Intermediate Spline Torque Capacity | The internal intermediate spline shaft carries only the torque demanded by the rear pump: T2 ≤ 30 Nm continuous. |
| Inlet Configuration Versatility | Configurable with separate independent suction inlets (for distinct hydraulic fluid circuits or isolated reservoirs) or an integrated common suction port to minimize external plumbing and fittings. |
| Integrated Control Valves | Available with integrated pressure relief valves (RV) or priority flow control valves built into the rear end-cover or intermediate plate. |
| 1:1 Direct-Fit OEM Brand Replacement Coverage
| Original Manufacturer | Direct-Fit Drop-In Tandem Equivalent Series |
|---|---|
| CASAPPA | POLARIS 10 Dual Series (PLP10+PLP10 / PL10+PL10 modular tandem gear pumps) |
| Bosch Rexroth | AZPF-1X + AZPF-1X / AZPB + AZPB Group 1 multiple gear pumps |
| MARZOCCHI | 1P + 1P / ALP1 + ALP1 / GHP1 + GHP1 modular tandem external gear pumps |
| PARKER Hannifin | PGP505 + PGP505 / PGP502 + PGP502 multiple section external gear pumps |
| DANFOSS / Turolla | SNP1NN + SNP1NN Group 1 dual external gear pumps |
| VIVOLO (Vivoil) | XV-1P + XV-1P / X1P multiple section gear pumps |
| SALAMI | 1.5PB + 1.5PB / 1.5PE + 1.5PE dual gear pump combinations |
| BUCHER Hydraulics | AP100 + AP100 multiple external gear pumps |
| Individual Stage Performance & Parameter Ratings (Group 1PDF)
| Stage Model Code | Displacement (cm³/rev) | Operating Pressure (bar) | Rotational Speed (r/min) | Theor. Flow @ 1500 rpm (L/min) | |||
|---|---|---|---|---|---|---|---|
| P1 (Continuous) | P2 (Intermittent) | P3 (Peak) | Max. Speed | Min. Speed | |||
| 1PDF1.4 | 1.40 | 250 | 275 | 300 | 4000 | 600 | 2.10 |
| 1PDF2.0 | 2.00 | 250 | 275 | 300 | 4000 | 600 | 3.00 |
| 1PDF2.8 | 2.80 | 250 | 275 | 300 | 4000 | 600 | 4.20 |
| 1PDF3.5 | 3.50 | 250 | 275 | 300 | 4000 | 600 | 5.25 |
| 1PDF4.1 | 4.10 | 250 | 275 | 300 | 4000 | 600 | 6.15 |
| 1PDF5.2 | 5.20 | 240 | 260 | 280 | 3800 | 600 | 7.80 |
| 1PDF6.2 | 6.20 | 230 | 250 | 270 | 3600 | 600 | 9.30 |
| 1PDF7.6 | 7.60 | 220 | 240 | 260 | 3500 | 600 | 11.40 |
| 1PDF9.3 | 9.30 | 200 | 220 | 240 | 3500 | 600 | 13.95 |
| 1PDF11.0 | 11.00 | 190 | 210 | 230 | 3000 | 600 | 16.50 |
| 1PDF13.8 | 13.80 | 180 | 200 | 220 | 3000 | 600 | 20.70 |
| Original Manufacturer | Direct-Fit Drop-In Tandem Equivalent Series |
|---|---|
| CASAPPA | POLARIS 10 Dual Series (PLP10+PLP10 / PL10+PL10 modular tandem gear pumps) |
| Bosch Rexroth | AZPF-1X + AZPF-1X / AZPB + AZPB Group 1 multiple gear pumps |
| MARZOCCHI | 1P + 1P / ALP1 + ALP1 / GHP1 + GHP1 modular tandem external gear pumps |
| PARKER Hannifin | PGP505 + PGP505 / PGP502 + PGP502 multiple section external gear pumps |
| DANFOSS / Turolla | SNP1NN + SNP1NN Group 1 dual external gear pumps |
| VIVOLO (Vivoil) | XV-1P + XV-1P / X1P multiple section gear pumps |
| SALAMI | 1.5PB + 1.5PB / 1.5PE + 1.5PE dual gear pump combinations |
| BUCHER Hydraulics | AP100 + AP100 multiple external gear pumps |
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