CASAPPA Hydraulic Gear Pump PLP20.25

| Overview of CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA is a POLARIS 20 multiple pump — the tandem version of the range. Casappa builds POLARIS pumps and motors in three pieces: a body extruded in high-resistance aluminium alloy, an external gear pair running on sleeve bearings with pressure-balanced thrust plates, and a separate mounting flange and rear cover that can be supplied in aluminium or cast iron. That layout gives a high power-to-weight ratio and keeps the wear surfaces controllable independently of the housing. In a multiple pump the sections are stacked on one shaft line, the section with the greater power requirement at the drive-shaft end, and the assembly is held together by one mounting flange at the front and a rear cover at the end.

Its function in a circuit is to draw oil from the reservoir and convert drive-shaft rotation into pressurised flow — here twice over, and at two different pressure levels. The front section is the PLP 20•25 gear set, 26.42 cm³/rev, rated 170 bar constant operating pressure, 190 bar system pressure and 210 bar peak, turning up to 2,500 r/min. The rear section is the PLP 20•16 gear set, 16.85 cm³/rev, rated 250 bar constant, 280 bar system pressure and 300 bar peak, and rated to 3,000 r/min as a single unit. Because the two sections sit on the same shaft, the assembly runs at one speed — and it is the lowest-rated of the two that sets it, so this tandem turns between 500 and 2,500 r/min.

The interfaces are written section by section. The drive end carries the SAE "B" spline shaft, code 04 — 13 teeth, 16/32 pitch, 30°, an external involute spline to SAE J498B with major diameter modified, flat root – side fit – class 1 — and it is mounted on the SAE "B" two-bolt cast-iron flange, code S5, which is the standard drive-shaft face for that shaft. Both sections take their ports on the side (position L): the front section inlet is MC, a 25.4 mm (1.00 in) port, and its outlet is MB, a 19 mm (0.75 in) port; the rear section inlet is MB, again 19 mm (0.75 in), and its outlet is MA, a 12.5 mm (0.49 in) port. All four ports are SAE flanged J518 ports of the 3000 psi standard pressure series with metric ISO 60° threads to ISO/R 262, so they take standard split-flange fittings.

The rotation is written once for the whole assembly: it is S, anti-clockwise looking at the drive shaft, and the version is the standard one, without outboard bearing. The seals are N, Buna NBR. Position 10 is L — a cast-iron mounting flange with an aluminium rear cover, which keeps a rigid cast-iron face against the driveline while saving weight on the cover at the far end of the assembly — and the code closes with FS, the female spline shaft arrangement.

Two pressures on one drive point is the reason to specify a tandem rather than two pumps: a PLP 20•16 section rated 250 bar continuous and 300 bar peak can hold a high-pressure service circuit while the PLP 20•25 section delivers 66.1 l/min at 2,500 r/min into a lower-pressure, higher-flow working circuit. The limit that governs the combination is torque, not pressure: the torque drawn from the drive shaft of the first pump is the sum of the torques of both sections, and on the standard PLP 20/20 tandem that sum must stay within 110 Nm (974 lbf in).

| Dimension of CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

[Drawing placeholder — insert the dimensional drawing screenshot here]

Reference dimensions published for the PLP 20/20 tandem with side-positioned ports. The letters correspond to the dimensional drawing.

The same drawing carries the torque limit of the assembly: 110 Nm (974 lbf in) for the standard-version PLP 20/20 tandem.

Interface data needed with the drawing:

| Pump Installation Specifications CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

A POLARIS 20 multiple pump is written as one section after another, separated by a slash: the section before the separator is the front section — the one at the drive-shaft end — and the section after it is the rear section. Reading the number is the fastest way to check that the assembly will fit an existing installation, because the front section fixes the drive interface and the rear section adds its own ports, its own displacement and an independent circuit.

Code structure — POLARIS 20 multiple pumps:

Position 5 is listed IN/OUT on a pump and OUT/IN on a motor, which is why the same two flanges appear in the opposite order on the motor side of the range. The flange codes are read by their first letter — a port code beginning with B is a German four-bolt flange, E is a European four-bolt flange, M is an SAE flange to the 3000 psi standard pressure series, S is an SAE flange to the SSS series, G is a GAS straight thread and O is a SAE straight thread.

| Reading your code: PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

| Assembly rules for POLARIS multiple pumps

• In applications where the input power requirement of each section varies, the section with the greater requirement must be at the drive-shaft end, and progressively smaller to the rear — as in this number, where the 26.42 cm³/rev front section carries the larger flow and the 16.85 cm³/rev section sits behind it.

• Features and performance are the same as the corresponding single pumps, but pressures must be limited by the transmissible torque of the drive and connecting shafts.

• The maximum rotational speed is that of the lowest-rated single unit incorporated — here 2,500 r/min, the rating of the PLP 20•25 front section, against 3,000 r/min for the PLP 20•16 rear section.

• The torque absorbed from the shaft of the first pump results from the sum of the torques due to all sections, and must not exceed the maximum torque limit given for the shaft of the first pump — 110 Nm (974 lbf in) for the standard PLP 20/20 tandem.

• The range is available in the standard version, with a common inlet and with separated stages; the standard version gives each section its own inlet and outlet, so the circuits stay independent.

Techspecs

Performance

Interfaces and configuration

Port data — SAE flanged ports J518, standard pressure series 3000 psi (SSM), metric thread ISO 60° to ISO/R 262

On each section the inlet is the low-pressure side and the outlet the high-pressure side, so the front section inlet MC is torqued to the low-pressure value and its outlet MB to the high-pressure value. MB appears twice in this configuration — as the outlet of the front section and as the inlet of the rear section — and the two are torqued differently: as an outlet it takes 25 +1 Nm (266 ÷ 288 lbf in), as an inlet 20 +1 Nm (177 ÷ 186 lbf in). MA is bolted to 15 +1 Nm (133 ÷ 142 lbf in) on both sides. For reversible rotation, only the high-pressure-side torque is used.

Operating conditions

Advantages

Two circuits from one drive point

A 26.42 cm³/rev front section and a 16.85 cm³/rev rear section on one shaft line give 43.27 cm³/rev and 108.2 l/min at 2,500 r/min, so a single take-off drives two circuits — for example a working circuit plus steering, pilot or cooling — with one mounting flange, one coupling and one set of suction and pressure lines per section.

Two pressure levels at the same time

The rear PLP 20•16 section is rated 250 bar (3,625 psi) continuous and 300 bar (4,350 psi) peak, the front PLP 20•25 section 170 bar (2,465 psi) and 210 bar (3,045 psi) peak. One drive point can therefore hold a high-pressure service circuit and a higher-flow working circuit on separate relief settings, instead of compromising both on a single pump.

Torque-checked build

The 110 Nm (974 lbf in) limit of the standard PLP 20/20 tandem is the governing constraint, and it is transparent on this configuration: 0.467 Nm per bar on the front section and 0.298 Nm per bar on the rear section, so a 170 bar front section plus a 92 bar rear section (106.8 Nm) or a 100 bar front section plus a 200 bar rear section (106.3 Nm) both stay inside the limit with margin.

Standard SAE drive interface

The code-04 SAE "B" 13-tooth spline shaft and the S5 two-bolt SAE "B" flange are a published standard combination in the POLARIS 20 range — the flange and the shaft are carried on the same mounting face, so the unit drops onto a group-2 SAE driveline without an adapter.

SAE flanged ports with published torque data

All four ports are SAE J518 3000 psi (SSM) flanges with metric ISO 60° threads to ISO/R 262, taking standard split-flange fittings: MC 25.4 mm, MB 19 mm on the front section and MB 19 mm, MA 12.5 mm on the rear section. The bolt torques, thread depths and flange diameters are published for each port and each pressure side, which removes guesswork at assembly.

Cast-iron mounting flange with aluminium rear cover

Position 10 is L: the flange that bolts to the machine stays cast iron for rigidity, while the cover at the far end of the assembly is aluminium — weight out of the least loaded part of the unit. Cast-iron flange with cast-iron cover, and all-aluminium builds, are available in the same code.

Three-piece construction per section

The extruded high-resistance aluminium alloy body, the sleeve-bearing gear pair and the separate mounting flange and rear cover are produced and inspected as individual components, so the wear surfaces are controlled independently of the housing.

Stable efficiency across the pressure range and across the working life

Pressure-balanced thrust plates compensate for wear, and the POLARIS range is specified for consistent volumetric and hydro-mechanical efficiency — so the flow each section delivers stays stable on a machine working at sustained load rather than at a test-bench point.

Low noise emission

The external gear design keeps running noise low, which matters on turf care, mower and fan-drive applications where the pump runs close to the operator.

Fifteen rear-section displacements available

The rear position accepts any POLARIS 20 size from PLP 20•4 to PLP 20•31,5, so the flow of the second circuit can be matched without changing the front section or the drive interface.

Common inlet and separated stages in the same code

The same tandem can be ordered with a common inlet (S7) when both sections should draw from one suction line, or as separate stages (Z6), so the suction arrangement can follow the machine rather than the other way round.

Wide combination choice

Sixteen drive shafts, European, SAE and German mounting flanges, GAS-thread, SAE-flanged and SAE-straight-thread port families, Viton and HNBR seals, wiper and high back-pressure shaft seals, and outboard-bearing versions W8, 5, 7, 8 and 9 let the same pump family be matched to an existing driveline, mounting and pipework.

Integrated outboard bearing option

For duty cycles that put radial load on the drive shaft, the same construction is available in versions with an outboard bearing.

Built-in valve options

The range can be ordered with several types of built-in valve, which removes external plumbing from the circuit.

6. Reference of CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

6.1 The POLARIS 20 range — same series, all displacements

Every size below is a valid position 1 in the POLARIS 20 ordering code, both as a single pump and as a section of a multiple pump. With p1 the constant operating pressure, p2 the system pressure (relief valve setting) and p3 the peak of pressure. The values refer to side-port unidirectional pumps; for reversible pumps the maximum pressures are 250 bar (3,600 psi), except the sizes whose rated value is lower.

The matching motor range is PLM 20, with the same displacements — the pump and the motor are alternative position-1 entries of the same code. Every one of these sizes can also be used as the rear section of a PLP 20/20 tandem, which is why the same two sections that make up this unit are also available separately as single pumps.

6.2 Complete order numbers of the POLARIS 20 range

Complete POLARIS 20 order numbers covering the PLP 20 range. Reference only — each number is valid only in the exact configuration it describes.

Complete order numbers of two-section POLARIS 20 units identified on the market:

Code examples in the published POLARIS 20 multiple-pump code structure:

7. Brand Replacement

HENGYUHANG supplies a replacement for the CASAPPA POLARIS 20 gear pump series, including PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA and the rest of the PLP 20 / PLM 20 size range from PLP 20•4 to PLP 20•31,5, as single pumps and as two-section units. The replacement is built to the same group-2 dimensional envelope and the same international standard interfaces — European, SAE and German mounting flanges, the same drive-shaft families and the same threaded or flanged port options — so a machine originally fitted with a Casappa POLARIS 20 unit can be returned to service without modifying the driveline, the mounting or the pipework.

Replacement units are supplied to the POLARIS 20 interface and dimension data. On a multiple pump the two sections, their order and their port pairs all have to be reproduced exactly, so please quote the complete original order number when enquiring.

8. Applications of CASAPPA PLP20.25-04S5-LMC/MB/20.16-LMB/MAS/FS-LA

Typical applications of the POLARIS 20 multiple-pump family:

Building and construction — a working circuit on one section and steering, supply or auxiliary circuits on the other, on compact machines, excavators and loaders

Material handling — lift, clamp, tilt and positioning circuits combined with a second service circuit on handling equipment, cranes and aerial platforms

Agriculture — implement hydraulics on one section and steering or auxiliary circuits on the other, on tractors, balers, harvesters, sprayers and seeders

Forestry — feed, conveyor and attachment circuits combined with a second function on forestry machinery

Turf care and mowers — deck lift, reel, traction and fan circuits fed from one drive point on wide-area mowers and turf equipment

Fan drive — a pump section feeding a hydraulic fan drive and engine cooling circuit alongside the machine's main circuit

In these machines the two sections typically feed unrelated functions, and the unit is expected to hold stable flow on both under sustained load, high duty cycles and demanding ambient conditions. The extruded aluminium-alloy body, the sleeve-bearing gear pair and the pressure-balanced thrust plates are what let each section keep its volumetric efficiency as circuit pressure and oil temperature rise; the SAE "B" flange and spline shaft let the assembly drop into a machine that is already built around group-2 interfaces; and the independent inlet and outlet of each section keep the two circuits separated all the way to the tank.

9. Package & Shipping

10. Why Choose Hengyuhang?

A hydraulic specialist, not a general trader. Quanzhou Hengyuhang Power Technology Co., Ltd. is based in Fujian, China and manufactures hydraulic gear pumps and motors, synchronous motors, multiple pump units, pumps with built-in valves and custom valve blocks.

One-piece minimum order. MOQ is one unit, so a single machine can be put back into service without committing to a production batch.

Model-level checking before you order. Send the complete original order number — for this page, the full PLP20.25-04S5-… tandem string — and both sections, their order, their port pairs and the drive interface are run against the POLARIS 20 dimension, flange, shaft and port data before the unit is built.

In-house production and testing. CNC machining centres, automatic gear heat-treatment lines, single-piece-flow assembly and an automatic hydraulic test bench, with ERP/MES traceability through production.

Replacement coverage across the range. The same plant supplies replacement units for a wide list of hydraulic brands and models, which keeps a mixed machine fleet on one supplier.

Customization support. OEM, ODM and OBM are offered, and customized packaging, graphics, nameplate and logo are available for distributor orders.

One-year warranty. Every unit is covered by a one-year warranty.

Responsive after-sales. Online support for installation and application questions.