Overview
ISO 7790:2013 - "Hydraulic fluid power - Four-port modular stack valves and four-port directional control valves, sizes 02, 03, 05, 07, 08 and 10 - Clamping dimensions" - defines the mounting (clamping) dimensions for four‑port directional control valves and modular stack valves on mounting surfaces. The standard aligns dimensions and sizes with ISO 4401 to ensure interchangeability, reduce the variety of fixing devices, and support consistent mounting across industrial hydraulic equipment.
Key topics and requirements
- Scope and applicability: Applies to four‑port modular stack valves and four‑port directional control valves in sizes 02, 03, 05, 07, 08 and 10 used in industrial equipment.
- Clamping dimensions: Provides preferred and alternative (non‑preferred) clamping dimensions (see Tables 1 and 2). Preferred dimensions are recommended for new valve designs to maximize interchangeability.
- Dimension definitions: Specifies symbols such as H:
- For directional control valves, H indicates clamping length for fixing devices (bolt heads).
- For modular stack valves, H indicates overall mounting height (including O‑ring plate when applicable).
- Mounting surface conformity: Mounting surface shall be in accordance with ISO 4401 to guarantee compatibility between different manufacturers.
- Tolerances and increments: References ISO tolerancing practices and allows H to be adjusted in specified increments where necessary for design reasons.
- Working pressure: The standard notes that suppliers shall establish maximum working pressure limits for valves, subplates and manifold blocks - ISO 7790 does not set a single working pressure value.
- Identification statement: Provides recommended wording for catalogues and test reports when declaring conformance.
Applications and users
- Who uses it: Hydraulic system designers, valve manufacturers, subplate and manifold block producers, procurement engineers, OEMs and maintenance teams.
- Practical benefits:
- Ensures mechanical interchangeability of four‑port valves across suppliers.
- Simplifies mounting hardware selection and reduces inventory of fixing devices.
- Speeds design and assembly of hydraulic manifolds and modular valve stacks.
- Reduces risk of misfit or rework when replacing valves in industrial machinery.
- Typical sectors: Industrial hydraulics, mobile machinery manufacturers, machine tool builders, materials handling and automation systems.
Related standards
- ISO 4401 - Four‑port directional control valves - Mounting surfaces (mounting interface referenced throughout ISO 7790)
- ISO 5598 - Fluid power systems and components - Vocabulary (terms and definitions)
- ISO 5783 - Code for identification of valve mounting surfaces and cartridge valve cavities
Compliance sample (as provided in ISO 7790):
“Modular stack valves and directional control valves clamping dimensions conform to ISO 7790, Hydraulic fluid power - Four‑port modular stack valves and four‑port directional control valves, sizes 02, 03, 05, 07, 08 and 10 - Clamping dimensions.”