Launch GOLD CUP® Pump Interactive Tool
Launch GOLD CUP® Pump Interactive Tool
Discover the Ultimate in Reliability and Performance.
Parker GOLD CUP® hydrostatic transmission pumps are variable displacement piston pumps of an unparalleled rugged design. Featuring unique technology, GOLD CUP offers an internal servo/replenish and the ability to utilize system over-pressure to directly control the stroking chambers. This affords the fastest and most stable control strategy available.
GOLD CUP controls are completely modular in design and can be configured to meet most any system requirements with standard factory options.
All internal wear surfaces are hydrostatically balanced and/or hydraulically linked allowing for a long and serviceable life. GOLD CUP pumps run in many open circuit applications, providing digital (Flow/Pressure) capability for the most difficult of control requirements.
The GOLD CUP Series has been designed to operate in a wide range of industries needing closed-loop control and high-pressure, high-power density. GOLD CUP performs in applications such as blast hole drill rigs, shredding, cranes, mining, hydraulic test stands, pulp and paper, military, marine, and power generation.
P6/7/8L
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 8 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V,VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
P6/7/8P
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 8 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P6/7/8R
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 4 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P6/7/8S
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 8 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
P6/7/8V
| Ports | Port Sizing | Identification Key |
| A | SAE 2.0 Code 61 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 8 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P6/7/8X
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 12 STR. THD | Case Drains |
| G | SAE 8 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| H | SAE 8 STR. THD | Servo Pressure Inlet From External Filter |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P11/14L
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG & AG3 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG & BG3 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K & K1 | SAE 12 STR. THD | Auxiliary Replenish Inlets from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
P11/14P
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| J | SAE 10 STR. THD | Internal Auxiliary Pump Outlet To External Filter |
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
| J1 | SAE 8 STR. THD | Internal Auxiliary Pump Outlet To External Filter |
P11/14R
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG & AG3 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG & BG3 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K & K1 | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
P11/14S
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
| J | SAE 8 STR. THD | Internal Auxiliary Pump Outlet To External Filter |
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
P11/14V
| Ports | Port Sizing | Identification Key |
| A | SAE 2.5 Code 61 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
P11/14X
| Ports | Port Sizing | Identification Key |
| A | SAE 1.5 Code 62 | System Port |
| B | SAE 1.5 Code 62 | System Port |
| AG | SAE 6 STR. THD | System “A” Gauge Connection |
| BG | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 4 STR. THD | System “A” & “B” Gauge Connections |
| C | SAE 20 STR. THD | Internal Auxiliary Pump Inlet |
| DG | SAE 6 STR. THD | Case Gauge Connection |
| D1 & D2 | SAE 16 STR. THD | Case Drains |
| G | SAE 4 STR. THD | Servo Outlet to External Filter or Gauge Connection |
| K | SAE 12 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 6 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| J | SAE 8 STR. THD | Internal Auxiliary Pump Outlet To External Filter |
| G2 | SAE 8 STR. THD | Servo Pressure Gauge Connection |
P24/30L
| Ports | Port Sizing | Identification Key |
| A | SAE 2.0 Code 62 | System Port |
| B | SAE 2.0 Code 62 | System Port |
| AG1 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG1 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 8 STR. THD | System “A” & “B” Gauge Connections |
| DG & H2 | SAE 6 STR. THD | “DG” Case Gauge Connection & “H2” Alternative Servo Inlet |
| D1 & D2 | SAE 20 STR. THD | Case Drains |
| H1 | SAE 12 STR. THD | “H1” Servo Pressure Inlet From External Filter |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 4 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
P24/30P
| Ports | Port Sizing | Identification Key |
| A | SAE 2.0 Code 62 | System Port |
| B | SAE 2.0 Code 62 | System Port |
| AG1 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG1 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 8 STR. THD | System “A” & “B” Gauge Connections |
| C | SAE 2.0 Code 61 | Internal Auxiliary Pump Inlet |
| DG & H2 | SAE 6 STR. THD | “DG” Case Gauge Connection & “H2” Alternative Servo Inlet |
| D1 & D2 | SAE 20 STR. THD | Case Drains |
| G | SAE 12 STR. THD | Servo Outlet To External Filter Or Gauge Connection |
| H1 | SAE 12 STR. THD | “H1” Servo Pressure Inlet From External Filter |
| K | SAE 32 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 4 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P24/30R
| Ports | Port Sizing | Identification Key |
| A | SAE 2.0 Code 62 | System Port |
| B | SAE 2.0 Code 62 | System Port |
| AG1 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG1 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 8 STR. THD | System “A” & “B” Gauge Connections |
| DG & H2 | SAE 6 STR. THD | “DG” Case Gauge Connection & “H2” Alternative Servo Inlet |
| D1 & D2 | SAE 20 STR. THD | Case Drains |
| H1 | SAE 12 STR. THD | “H1” Servo Pressure Inlet From External Filter |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 4 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side |
P24/30S
| Ports | Port Sizing | Identification Key |
| A | SAE 2.0 Code 62 | System Port |
| B | SAE 2.0 Code 62 | System Port |
| AG1 | SAE 6 STR. THD | System “A” Gauge Connection |
| BG1 | SAE 6 STR. THD | System “B” Gauge Connection |
| AG2 & BG2 | SAE 8 STR. THD | System “A” & “B” Gauge Connections |
| DG & H2 | SAE 6 STR. THD | “DG” Case Gauge Connection & “H2” Alternative Servo Inlet |
| D1 & D2 | SAE 20 STR. THD | Case Drains |
| G | SAE 12 STR. THD | Servo Outlet To External Filter Or Gauge Connection |
| H1 | SAE 12 STR. THD | “H1” Servo Pressure Inlet From External Filter |
| K | SAE 16 STR. THD | Auxiliary Replenish Inlet from External Filter |
| KG | SAE 6 STR. THD | Replenish Gauge Connection |
| FA & FB | SAE 4 STR. THD | Control Chamber Gauge Connection “A” & “B” Sides |
| V, VA & VB | SAE 4 STR. THD | “V” Compensator Vent “A” & “B” Sides |
| “VA” Compensator Vent “A” Side | ||
| “VB” Compensator Vent “B” Side | ||
| KA | SAE 12 STR. THD | Shuttle Relief Inlet |
| D3 | SAE 16 STR. THD | Shuttle Drain |
| DV | SAE 4 STR. THD | Shuttle External Pilot Valve Drain |
Cam
Also known as the "Rocker Cam," the cam varies the displacement of the main pump as it rotates within the rocker cradle. System pressure exposed to a small area of the rocker cradle is used to hydrostatically balance (partially float on a thin film of oil) the cam to reduce stroking friction.
Compensator Adjustment
The compensator adjustment allows the user to limit the system's maximum operating pressure. This combination of cone, spring and seat functions as the pilot relief stage to the sequence poppets, which open to channel system flow directly into stroking chambers to rapidly reduce the pump displacement.
Cradle
The cradle provides the system with flow passages to the back side of the cam to achieve hydrostatic balance for smooth, precise stroking. The cradle also contains drilled passages to communicate the control pressure from one side of the pump to the other. The result is equal forces in both vane chambers to eliminate unbalanced or side loading of the cam.
Dual Level Relief Poppets
The valve block contains two dual level relief poppets. Their main function is to relieve pressure into and out of the vane chamber as the pump begins to compensate and rapidly destroke the cam. The internal valve block logic allows these poppets to relieve at two different levels, depending on which leg is operating as the system work port. The poppets can also act as cross-port relief functions under critical circumstances.
Filter
The filter is part of an assembly that includes the control orifice to the replenish relief pilot stage. This assembly delivers clean fluid to the pilot stage, but, more importantly, helps ensure the proper function of two-stage replenish relief.
Input Servo Arm
The servo arm is pressed onto and rotates with the servo shaft. As labeled, the "input" servo arm commands the cam of the pump or motor to follow, providing an output flow proportional to the angle of rotation. The moving parts of this control are fully hydrostatically balanced with no mechanical linkage. Full range of motion is +/-19 degrees, which equates to +/-100 percent displacement.
Isolation Checks
These check valves isolate system pressure within the valve block based on the highest work port operating pressure. In addition, they also provide a convenient method of independent pressure control of the system work ports via pilot relief valves connected to the VA and VB vent ports without additional complex plumbing.
Modulating Pin
The modulating pin provides automatic regulation of servo (or control) pressure, based on the highest system pressure leg. System pressure acting on the top of this pin provides additional force to the servo poppet, hence, increasing the servo relief (control pressure) setting. More force is required to hold the cam on stroke when operating at a high system pressure. This energy saving concept does just that.
Replenish Pilot Relief Valve
This pilot valve works in conjunction with the replenish poppet to create a two-stage relief valve, used to set the system replenish (or boost) pressure. The pilot relief is integrated into the valve block and pre-set at the factory during production testing. Securing the valve in the valve block also provides the benefit of making it more tamper resistant.
Replenish Poppet
The replenish poppet has a 2:1 area ratio and acts as the main stage of the replenish relief valve. Flow spilling across is poppet dumps into the case of the pump to provide cooling.
Ring Checks
These unique cylindrical shaped spring steel strips act as replenishing check valves to the main system work ports. Their design allows much faster action than conventional check valves. Transferring high flow at a low pressure drop contributes to achieve high overall efficiency.
Sequence Poppets
The sequence poppets have a 1:1 area ratio and are the only poppets with a hole in the bottom to allow fluid to pass through. During normal operation when the system pressure is below the compensator setting, these poppets remain closed. The internal spring keeps the poppet seated with equal pressure on the top and bottom of the poppet, equivalent to the system work port. When system pressure reaches the compensator setting, the compensator cone unseats, allowing flow to pass through the sequence poppet. This creates a differential pressure across the sequence poppet and overcomes the spring force holding it closed. When the sequence poppet lifts, system flow dumps into the over-ride tubes and into the vane chambers to de-stroke the pump. The sequence poppet continues to modulate until system pressure pressure drops below the compensator set point.
Servo Poppet
The 2:1 area servo poppet functions as a relief valve to limit the control flow pressure used to stroke the pump. This setting is automatically adjusted based on the replenish pressure setting and the force applied by system pressure acting on the modulating pin. Once the flow requirements are met for stroking the pump, the remaining flow that spills across this servo poppet will feed into the replenish circuit.
Servo/Replenish Pump
This internal pump provides flow to control the pump displacement, replenish fluid lost due to internal leakage, and exchange fluid for cooling the hydrostatic loop. The 6/7/8 frame size uses a single 1.07cipr (17.5cc) gerotor to perform these functions, with priority to the control. The 11/14 frame size uses two of this same gerotor. However, one is used for control flow (servo), and the other is used for the replenish/cooling circuit. Any flow additional flow that is not required for displacement control is diverted to the replenish/cooling circuit. The 24/30 frame size unit uses a single vane cartridge (with displacement choices from 1.05cipr/17.2cc to 6.1cipr/100cc) for the control/replenish/cooling.
System Ports
The system work ports are labeled "A" and "B." Fluid travels through these ports in either direction based on the cam position of the pump. Pressure in these ports should be at the replenish pressure setting or higher for closed circuit applications.
Vane Chamber
The vane chambers are located on both sides of the cam and cradle assembly to provide equal and balanced forces to stroke the pump. During normal operation, fluid is controlled to the vane chambers to change pump displacement via the servo arm. During pump compensation, high flow can be transferred to the vane chambers through the over-ride (see sequence poppet) tubes for rapid stroking of the pump.
Vent Ports
The valve block contains three vent ports (V, VA, & VB). These ports can be used for remote control of the compensator setting by connecting a pilot relief valve and adjusting the interal compensator above your working pilot relief setting. Connecting directly to the V port will limit the system pressure in the A & B leg to the pilot relief setting. If the application requires different settings on the system legs, pilot relief valves can be connected to the VA and VB ports to obtain independent pressure settings. Contact our tech support team for built-on electronic proportional pressure control solutions.