LHDV33 HAWE Load-Holding Valve 420 Bar

Product Overview

LHDV33 is a HAWE Hydraulik load-holding valve series designed to control uncontrolled movement of hydraulic cylinders and motors under overrunning or negative-load conditions.

The LHDV design incorporates dedicated damping characteristics for hydraulic circuits that are prone to oscillation. HAWE specifically identifies applications involving cranes, construction machinery and lifting equipment, and highlights its suitability for use with proportional directional spool valves such as PSL and PSV. When the valve is fully closed, the design provides zero leakage.

The valve controls the return flow from the actuator during load movement. Hydraulic pilot pressure progressively opens the load-holding element, allowing controlled lowering while preventing uncontrolled acceleration caused by gravity or overrunning loads. Its damping system is particularly valuable during starting, stopping and rapid speed transitions where conventional load-holding arrangements may generate oscillation.

For replacement applications, LHDV33P-15-L6-400/440 and LHDV33-21-B6-180/180 represent specific LHDV33 configurations. The legacy LHDV 33-35 WD-C 6-180/180-150/ designation is also present in market records; however, this exact “35 WD-C” configuration is not listed in the current 2024 HAWE D7770 documentation, so its final dimensions and configuration should be confirmed from the original nameplate or drawing before direct replacement.

Technical Specifications

LHDV33 Series

• Manufacturer: HAWE Hydraulik SE
• Series: LHDV
• Basic Type: LHDV 33
• Valve Type: Load-Holding / Over-Center Valve
• Valve Element: Cone-seated piston valve
• Maximum Flow Rate: 80 L/min
• Maximum Pressure Setting: 420 bar
• Maximum Load Pressure: 350 bar according to the current HAWE documentation
• Permitted Return Pressure: 10 bar
• Leakage: Zero leakage
• Material: Steel
• Internal Parts: Hardened
• Control Principle: Hydraulic pilot control
• Pilot Ratio: approximately 1:8.2 to 1:1.2, depending on orifice selection
• Standard D2 Orifice: 0.6 mm for code 6
• Pilot Ratio for Code 6: approximately 1:2.9
• Standard D1 Inlet Orifice: 0.5 mm
• Hydraulic Fluid: DIN 51 524 Part 1–3 / ISO VG 10–68
• Viscosity Range: 4–1500 mm²/s
• Recommended Operating Viscosity: approximately 10–500 mm²/s
• Ambient Temperature: approximately -40 to +80 °C
• Hydraulic Fluid Temperature: approximately -25 to +80 °C
• Required Cleanliness: approximately ISO 4406 21/18/15 to 19/17/13

LHDV33P-15-L6-400/440

• Model: LHDV 33 P-15-L6-400/440
• Configuration: P-15 single manifold-mounted load-holding valve
• Flow Code: L
• Maximum Flow: 80 L/min
• Orifice Code: 6
• D2 Orifice: 0.6 mm
• Pilot Ratio: approximately 1:2.9
• Load-Holding Pressure Setting: 400 bar
• Shock Valve Setting: 440 bar
• Main Ports: F / V = G 1/2
• Additional Ports: R = G 3/8; M / S / Z = G 1/4
• Approximate Weight: 1.8 kg

The 400/440 bar configuration should be treated as a legacy configuration interpretation rather than a current standard example. HAWE’s historical documentation permits load-holding settings up to 420 bar and shock-valve settings up to 450 bar, while the current 2024 documentation lists a maximum pressure setting of 420 bar.

LHDV33-21-B6-180/180

• Model: LHDV 33-21-B6-180/180
• Configuration: Twin valve for alternating load direction
• Flow Code: B
• Maximum Flow: 60 L/min
• Orifice Code: 6
• D2 Orifice: 0.6 mm
• Pilot Ratio: approximately 1:2.9
• Load-Holding Setting V1: 180 bar
• Load-Holding Setting V2: 180 bar
• Approximate Weight: 3.5 kg
• Control: Internal hydraulic pilot control; standard twin-valve versions do not require external control pipes for the load-release function.

LHDV33-35 WD-C6-180/180-150/

• Model: LHDV 33-35 WD-C6-180/180-150/
• Configuration: Legacy twin load-holding / brake-related configuration
• Orifice Code: 6
• Specified Load-Holding Settings: 180/180 bar
• Additional Pressure Code: 150/… as supplied in the original part number
• WD Function: Related to an additional restrictor/check-valve arrangement used in LHDV configurations for controlled brake release and prevention of sudden brake engagement.
• Verification Status: Exact flow, mass and dimensional data for the specific “35 WD-C” configuration should be confirmed against the original valve because this designation is not present in the current 2024 HAWE D7770 document.

Not Applicable

• Displacement: Not applicable — hydraulic valve, not pump/motor
• Maximum Speed: Not applicable — hydraulic valve, not pump/motor

Key Technical Advantages

1. Dedicated Oscillation Damping

LHDV33 is engineered for hydraulic systems susceptible to oscillation. Its damping elements delay and weaken pilot response, helping suppress pendulum motion generated by hydraulic elasticity, variable load pressure and rapid flow changes.

2. Hardened Internal Components

The official HAWE documentation specifies a steel construction with hardened internal parts. This architecture supports mechanical durability in high-pressure, cyclic hydraulic applications where valve-seat wear and repeated pressure loading are critical factors.

3. High-Pressure Capability

The LHDV33 platform supports pressure settings up to 420 bar and flow configurations up to 80 L/min, making it suitable for high-pressure mobile hydraulic circuits.

4. Tunable Pilot Characteristics

The D2 orifice and corresponding pilot ratio influence valve opening behavior. Code 6 uses a 0.6 mm orifice and an approximate 1:2.9 pilot ratio, allowing the valve response to be matched more closely to the dynamics of the hydraulic circuit.

5. Zero Leakage in the Closed Condition

HAWE explicitly specifies zero leakage when the LHDV valve is fully closed, which is essential for maintaining actuator position and preventing unwanted load drift.

6. Single and Twin-Valve Configurations

The LHDV33 family includes single-valve and twin-valve configurations for constant or alternating load directions. Twin designs are particularly useful for hydraulic cylinders and motors that experience load reversal.

Application Areas

• Mobile cranes
• Construction machinery
• Hydraulic lifting systems
• Heavy-duty hydraulic cylinders
• Hydraulic winches
• Hydraulic motors and slew drives
• Load-sensing hydraulic systems
• Hydraulic brake release circuits
• Proportional hydraulic valve systems using PSL / PSV technology

Expert Maintenance Tips

Verify the complete ordering code.
Do not replace an LHDV33 solely by matching the family name. Codes such as P-15, L, 6 and 400/440 define installation style, flow range, orifice and pressure configuration.

Use a pressure gauge during adjustment.
HAWE’s documentation recommends using a pressure gauge whenever the load-holding pressure is adjusted or changed. The setting should be selected above the maximum expected load pressure according to the applicable design conditions.

Secure the spring housing during fitting.
For P-15 configurations, the HAWE installation information instructs the installer to hold the hexagonal spring housing while tightening hydraulic fittings to prevent unwanted loading of the adjustment mechanism.

Keep hydraulic contamination under control.
The small pilot/orifice passages make oil cleanliness critical. Contamination can change pilot behavior, degrade sealing and cause unstable pressure response.

Verify WD/W functions before replacement.
Variants such as 21, 21W, 21WD and 25WD have different hydraulic functions. A WD version, for example, incorporates an additional restrictor/check-valve arrangement associated with controlled hydraulic brake engagement. A visually similar replacement is not necessarily functionally equivalent.