Overview
ISO 3963:1977 - "Fertilizers - Sampling from a conveyor by stopping the belt" is a reference method for taking representative samples of solid fertilizers from conveyor belts. Intended for use when automatic sampling or free-fall scoop sampling is impossible, or when a reference procedure is required to validate other sampling techniques, the method involves stopping the belt, inserting two parallel boards or metal sheets across the stream, and removing the material captured between them.
Key Topics and Requirements
- Scope and purpose: A reference method for sampling solid fertilizers transported on a conveyor belt from manufacture or storage to another location. The method is time‑consuming and interrupts handling operations, so it is reserved for special circumstances or verification use.
- Apparatus: Two parallel boards or metal sheets shaped to the belt trough, sized to project beyond the belt edges and with an upper edge above the fertilizer layer. A metal frame to carry the boards is recommended to enable single‑operation insertion.
- Safety: Ensure the conveyor cannot start during sampling. Provide an override start/stop control at the sampling point or mark fixed insertion points so boards can be repeatedly placed in the same locations. The sampler must be able to reach the full cross‑section without undue strain.
- Procedure:
- Select a position where fertilizer is well spread and the stream stabilized (at least 1 m from feed).
- Stop the belt; do not sample during start-up or when feed is low or finishing.
- Insert the two boards vertically and at right angles to the stream and belt axis, spaced to yield an increment above the minimum required mass.
- Remove the material between the boards into a suitable airtight container, following guidance on handling obstructing material (downstream material pushed into the sample, upstream material pushed out).
- Restart the belt and ensure no debris remains.
- Repeat increments as required by the sampling scheme to form the final sample.
- Documentation: The sampling report must include identification details, the method used (with reference to ISO 3963:1977), sampling conditions, and any deviations or additional operations that could influence results.
Applications and Users
ISO 3963:1977 is used by:
- Quality control and laboratory teams at fertilizer manufacturers
- Inspection agencies and regulatory bodies verifying consignments
- Bulk handling operators and storage facility managers needing a validated reference method
Practical uses include spot verification of automated samplers, dispute resolution, proficiency testing, and situations where conveyor configuration precludes other sampling methods.
Related Standards
ISO 3963:1977 references other ISO documents on fertilizer sampling and sampling reports for increment sizing, sampling frequency, and reporting content. Users should consult the current ISO series on fertilizer sampling and reporting for complementary procedures and updated requirements.
