Weighing Machines
Operation of the linear automatic weighing machine
The automatic weighing machine is developed for weighing granular products, small and large pieces, fragile products and products susceptible to scratching.
An automatic weigher can contain one, two, three or four separate weighing systems (1, 2, 3 or 4 heads) Each weighing system consists of a load cell (or weighing cell in older versions), a weighing bucket and a set of vibrating feeders, a control system with power supply and a feeder device.
The set of vibrating feeders consists of an upper feeder, lower feeder and fine feeder. The coarse valve and fine valve at the end of the lower feeder and fine feeder accurately stop the product flow at the end of the coarse and fine flow phase. The valves are operated by rotating cylinders or magnets. The weigh bucket is opened by a linear cylinder or rotating magnet. The vibrating feeders are driven by solenoids. Their vibrating capacity can be adjusted on the screen or by using potentiometers.
The amount of product flowing out of the feeder device into the upper feeder is controlled by an electronic sensor. The layer thickness can be adjusted on the screen. If the machine is equipped with dosing scales (lever with sliding weight), it is possible to use the sliding weight to adjust the layer thickness.
The feeder hopper with a volume of 40 to 90 litres (depending on the type) is very suitable for delicate products which can be adversely affected by large accumulations. However, this hopper requires a steady product supply, because an empty hopper can lead to bad weighing results.
Depending on the type of machine, all machine settings can be entered in the control system or adjusted with potentiometers.
If you change products or weights in machines with potentiometers, use these potentiometers to make adjustments. In machines with touchscreens it is possible to save programmes, so you only have to select a saved programme if you change or weights or products.
Long and short version
Two different versions of a linear automatic weighing machine are shown below. There are different types available for each version in various widths and, for example, with various weighing heads. Each type of machine has its own applications regarding products, required speed and accuracy.
Differences between the 2 versions
The short machine is very suitable for powders and granulates such as tea, rice, coffee, sugar, salt, flour, plastic granulates, pet food, etc. It has only 1 vibrating feeder which transports the product to the weighing bucket.
The long machine is suitable for weighing products which are more difficult to transport by the vibrating feeder in the short machine, due to their unit weight, size and/or product qualities. This type of machine has several vibrating feeders in a row for better levelling, so a constant, uniform layer of products can be transported to the weigh bucket, which improves accuracy. Products that are suitable for a long machine are, for example, sliced (fresh and frozen) vegetables, shrimps, grated cheese, crisps, cookies, sweets, nuts, screws, washers, etc.
This type of machine can be equipped with wide or narrow vibrating feeders, depending on the product weight and volume.
Versions with 1, 2, 3 or 4 heads
Depending on the required number of weighings per minute, linear automatic weighing machines are available with 1, 2, 3 or even 4 heads.
|
