Overview

This document details the specifications, configurations, and technical data for modular cartridge flow control valves of types LIQV and LIDD, compliant with ISO 7368 standards. These valves are designed for hydraulic systems, offering flow control capabilities with sizes ranging from 16 to 63 and maximum flow rates up to 3500 l/min at a differential pressure of 6 bar, and maximum operating pressures up to 350 bar.

1. Valve Components and Construction

• Covers: Referenced in section 2, covers house the manual setting mechanism and interface with the cartridge.
• Spools and Poppets: The cartridge contains either a spool (LIQV) or a poppet (LIDD) sliding within a drilled sleeve (sections 3 and 4). The spool or poppet position regulates flow and is manually adjusted via the cover.
• Spring Cracking Pressure: For poppets, cracking pressure depends on the spring used, with options ranging from 0.3 bar to 6 bar.

2. Sizes and Performance Parameters

• Valve sizes: 16, 25, 32, 40, 50, 63 (sizes 40, 50, 63 are exclusive to LIDD models).
• Maximum flow rates at Δp = 6 bar vary by size and model, from 60 l/min (size 16) up to 3500 l/min (size 63).
• Maximum operating pressures reach up to 350 bar at ports A, B, and X.

3. Model Coding and Options

• Covers: Model codes start with 'LI' followed by size and type (e.g., QV for manual setting, DD for normally closed with stroke limiter).
• Spools and Poppets: Codes indicate size, spring cracking pressure, and series number (e.g., SC LI 43).
• Options: For LIQV, a lock key option (/K) is available for the setting knob. For LIDD, external attachments (/E) and calibrated plugs can be specified.
• Seals: Standard seals are NBR for mineral oil and water glycol; FPM (PE) seals are optional for higher temperature ranges.

4. Hydraulic and Operating Characteristics

• Area ratio (pressure application area vs. pilot pressure area) varies by size and model, affecting valve regulation.
• Assembly position is flexible; valves can be installed in any orientation.
• Surface finishing requirements for subplates: Roughness index Ra 0.4 and flatness ratio 0.01/100 mm (ISO 1101).
• Operating temperature range: -20°C to +70°C standard; up to +80°C with FPM seals.
• Recommended hydraulic fluids comply with DIN 51524 standards; viscosity range 15 to 100 mm²/s at 40°C.
• Fluid contamination must meet ISO 4406 class 21/19/16 or NAS 1638 class 10, with 25 μm filters recommended.

5. Functional Diagrams and Performance Curves

• Regulation and operation diagrams for spools and poppets illustrate flow versus differential pressure and knob turns.
• Spool types (290, 490) and poppet types (32, 33, 42, 43) are identified with corresponding hydraulic symbols and performance characteristics.

6. Dimensional Data

• Recess Dimensions: Detailed dimensions for valve recesses are provided for all sizes, including diameters, lengths, and tolerances.
• Cover Interface Dimensions: Dimensions for covers include port sizes, fastening bolt specifications, weights, and tightening torques.
• Fastening Bolts: Hexagon socket head screws per DIN 912 class 12.9 are specified, with sizes and torque values varying by valve size.

7. Installation and Assembly Recommendations

• Ensure correct matching of covers, spools, and poppets according to model codes and sizes.
• Use recommended seals and verify fluid compatibility.
• Follow specified tightening torques and bolt types to ensure secure assembly.
• Maintain cleanliness standards to avoid contamination and ensure valve longevity.

Critical Information Summary

• Maximum flow: up to 3500 l/min at 6 bar differential pressure.
• Maximum pressure: 350 bar at ports A, B, X.
• Valve sizes: 16 to 63 (ISO 7368 standard).
• Manual flow regulation via spool or poppet position on cover.
• Seals: NBR standard, FPM optional for higher temperature.
• Fluid requirements: DIN 51524 compliant hydraulic oils, viscosity 15-100 mm²/s.
• Contamination control: ISO 4406 class 21/19/16 or better, 25 μm filtration recommended.
• Installation: Any position, with specified surface finish and flatness for subplates.