Frequently Asked Questions (FAQ)

Q1: What is the function of the "DFR1" control?

A:​ The DFR1​ is a combined Pressure and Flow Controller. It provides two key functions:

1. Pressure Limiting: Acts as a pressure compensator, destrokeing the pump when system pressure reaches the set value.

2. Load Sensing (Flow Control): Automatically adjusts displacement to maintain a constant pressure differential (Δp) across a downstream orifice, providing load-independent flow control for improved energy efficiency.

Q2: What does the "VPA12N00" suffix indicate?

A:​ This code defines the mechanical configuration:

• V: FKM (Viton)​ seals, offering superior chemical and temperature resistance.

• P: Tapered shaft​ (1:5) with a parallel key.

• A12: Port size code 12​ (metric threads).

• N00: No through-drive​ (solid shaft end, cannot mount additional pumps on the shaft).

Q3: What is the key difference between this A10VSO28 and the previously mentioned A10VSO18?

A:​ The primary difference is the displacement size:

• A10VSO28: 28 cm³/rev, providing higher flow output (~84 L/min vs ~59 L/min at same speed).

• A10VSO18: 18 cm³/rev, smaller size for lower flow requirements.

  Both share the same DFR1 control type and Series 31 design.

Q4: What are the X and L ports used for?

A:​

• X Port (Control): Load-Sensing (LS) Feedback. It connects to the downstream system to sense the load pressure, allowing the pump to adjust its displacement to maintain the set Δp.

• L Port (Case Drain): Must be connected directly to the tank. It relieves internal leakage pressure to protect the shaft seal (max backpressure typically 2 bar).

Q5: Can this pump be used in a closed-loop system?

A:​ No.​ The A10VSO DFR1 is designed exclusively for open-circuit applications​ (pump → valve → actuator → tank). For closed-loop hydrostatic transmissions, you would need an A4VG or A2FM series unit.