Laboratory manual for the evaluation of non-automatic weighing devices
Part 2, section 11—Load receiving/weighing element
Table of contents
Sections 30 to 33 of the Specifications Relating to Non Automatic Weighing Devices (1998)
11.0 Load receiving/weighing element–generalities
Scales used to weigh wet commodities such as fish, lobster, etc. are required to have a load-receiving element, generally a scoop or platform with raised edges, to effectively drain off liquid that would tend to accumulate on the scale. This requirement does not apply to small computing scales such as those used in supermarkets since few wet commodities are weighed. In those particular applications, the scoop or platter can be easily removed and cleaned to maintain the zero balance condition.
11.1 If the load receiving element is designed to receive wet commodities, it must also be designed to drain effectively.
11.2 Tank or hopper scales and their associated piping or conduit must be designed to ensure proper drainage and complete delivery of products.
Scales must be designed such that the normal movement of load receiving elements (platform, pan, etc.) during use will not "bind" and interfere with the weighing operation. This is checked by shifting the load receiving element when loaded. Mechanical systems must be designed to reduce frictions.
11.3 The load receiving/weighing element is designed to remain centrally aligned under load; lateral movements of the platter or platform do not cause bindings or frictions that interfere with the weighing operations.
If a device has a locking feature, this feature must only have two stable positions corresponding to "lock" and "weigh" (no intermediate position), and weighing must only be possible in the "weigh" position. Electronic digital devices must "blank" and inhibit printing in the "locked" position.
11.4 The device locking feature (if any) has only two positions: "locked" and "weigh".
11.5 Weighing is possible only in the "weigh" position, and the locking feature does not interfere in any way with the weighing operation.
11.6 Overload protection (stoppers) must be set so that they do not interfere with weighing operation.
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