ISO 7805-1:1984

Overview

ISO 7805-1:1984 - Industrial plate screens (thickness 3 mm and above) specifies standardized perforation patterns, sizes and tolerances for industrial sieve and screen plates manufactured from low‑carbon steel. The standard defines three hole arrangements (round and square perforations), nominal hole sizes from 125 mm down to 3.15 mm, and five prescribed pitch-to-hole ratios that produce nominal open areas roughly 64% down to 23%. Measurement and designation rules are included to support consistent manufacturing and ordering.

Key topics and technical requirements

• Perforation patterns
  • Round (circular) holes in a 60° staggered (equilateral triangle) arrangement.
  • Square holes in in-line and half‑pitch staggered arrangements.
• Hole sizes and pitch
  • Nominal hole sizes follow preferred number series (R10 first choice; R20/R40 as alternatives).
  • Five pitch/hole ratio options are tabulated, with corresponding approximate open areas.
• Material and plate thickness
  • Intended for low‑carbon steel plate of 3 mm thickness and above. Plate thickness before perforation is agreed between purchaser and supplier; chosen thickness is normally less than the hole size and bridge width.
• Tolerances and measurement
  • Formulae are provided for tolerance on average hole size and average pitch; tolerances on individual pitch are specified (notably, tolerance on any individual pitch is twice that stated for average pitch).
  • Measurements of hole size and pitch are to be taken at the punch side, in accordance with test methods referenced from ISO 3310/2.
• Designation
  • A codification system for describing shape, size, arrangement and pitch is referenced (ISO 7806).

Practical applications

ISO 7805-1 is used to specify and standardize perforated plate screens and sieve plates for industrial sizing and separation tasks. Typical uses include:

• Screening and grading in mineral processing, aggregates and quarrying
• Sizing and separation applications in recycling, chemical and bulk material handling
• Manufacture and procurement of plate screens, replacement sieve plates and custom perforated panels
• Quality control and inspection during production of perforated plates

Who uses this standard

• Design and process engineers specifying screen media
• Manufacturers of perforated plates and sieve plates
• Purchasing and procurement teams creating technical orders
• Test laboratories and QA teams performing dimensional checks
• Standards bodies mapping national requirements to international practice

Related standards

• ISO 7805-2 (industrial plate screens - thickness below 3 mm)
• ISO 7806 (codification for designating perforations)
• ISO 3310-2 (test sieves - metal perforated plate testing)
• ISO 2194, ISO 2395, ISO 3 (preferred numbers and vocabulary references)

Keywords: ISO 7805-1, industrial plate screens, perforated plate, low carbon steel, hole size, pitch-to-hole ratio, open area, sieve plates, screening, tolerances.