Load cells help optimise growth weight

A provider of control and instrumentation systems for poultry farmers is using single-point load cells from Applied Measurements on bird weighing and feed hopper systems.

Supermarkets now specify that poultry farmers must supply fixed-weight priced birds.

If, for example, a poultry farmer is supplying 4lb oven-ready chickens with a tolerance range of 3.9 to 4.1lb to a supermarket, for birds that weight less than 3.9lb, the supermarket will deduct monies from the final payment.

If the birds are overweight and exceed 4.1lb, the farmer is giving away product since there is no extra payment for this additional weight because payment is based on the number of birds supplied.

This means that the load cells used on weighing systems are important in ensuring that accurate weight measurements are made and that bird weight and feed can be optimised accordingly.

The load cells often also need to operate in dusty and wet conditions.

CF Whaler, based in Wragby, Lincolnshire, is using two types of single-point load cells from Applied Measurements.

CF Whaler designs, manufactures and installs electrical and electronic environmental control systems and equipment for the agricultural industry.

Applied Measurements has been working with CF Whaler for about 10 years, supplying its OBU series of single-point load cells for use in two CF Whaler products.

CF Whaler's bird weighing system, which uses the company's Stick controller, enables the poultry farmer to record bird weights automatically by capturing individual weights and calculating an average.

The unit is portable and the display/controller can be plugged in to any nearby 13A socket.

The platform is designed in the shape of a tunnel in order to protect the bird being weighed from interference by the surrounding flock.

Two separate size restriction plates are provided to further increase the number of valid bird weights by preventing multiple birds perching together.

Readings available from the system include average weight, current average, previous 24-hour average, number of birds weighed and last bird weight.

Mark Thorp, technical director at CF Whaler, said: 'We selected the OBU series load cells from Applied Measurement because they provide us with the accuracy, long-term stability and environmental protection that our weighing systems require.

'We also need to respond very quickly to requests from poultry farmer customers, who often need weighing units very quickly.

'Applied Measurements delivers load cells to us often at very short notice, within one week on some occasions.' The Stick bird weighing system uses the OBUG series load cell from Applied Measurements, which is mounted at the bottom of a platform that the birds can perch on.

The OBUG is a moment-insensitive, single-point load cell, which means only one unit is required centrally positioned to make a weighing system.

Before this type of design was introduced to the market, three or four separate load cells would be required to perform the same task.

Sealed to IP65, the OBU series is available in capacities from 0.5kg up to 1,000kg.

CF Whaler uses the 10kg version on its portable bird weigher.

Peter Lewis, managing director at Applied Measurements, said: 'The OBU series of load cells were originally intended for industrial and laboratory scale tasks, but they are equally suited to a wide range of force measurement applications.

'The design of the OBU combined with the volume manufacturing techniques used to build this series of load cells makes it an ideal solution for applications in which low forces are to be measured within a tight budget.' The OBU series is a robust, high-accuracy load cell that can be sealed to IP67 (IP65 is standard) for damp and wet conditions.

Extra mechanical protection can be provided by adding overload stops.

The load cells are constructed from anodised aluminium alloy (stainless steel versions are also available) providing a lightweight unit.

The load cells can also be supplied calibrated as a complete system with any instrumentation products from Applied Measurements.

CF Whaler also uses load cells from Applied Measurements on its Stick feed hopper/blender systems.

The larger, OBUC-100 single-point load cell is mounted across the top of the feed hopper, with the feed weigher suspended from the load cell.

The OBUC-100 has a capacity of 100kg and is provided with sense wires for compensation of voltage drops along the load cell cable.

The feed hopper system enables the farmer to make adjustments to the mix of the bird feed using a simple joystick controller.

Both the Stick portable bird weigher and Stick feed hopper have a load cell amplifier mounted to the side of the equipment, which is connected to a remote computer with digital display and joystick controller.

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