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LOSS IN WEIGHT
Loss-In-Weight (LIW) Feeders are generally the most accurate of all continuous weighing devices. These systems have particular application where precision and accuracy is essential.
Loss-In-Weight Feeders are generally used to deliver precise control for:
- Low throughputs,
- Blending,
- Managing the feed rate of minor additives.
Loss-In-Weight Feeders can be:
- Belt Fed,
- Screw Fed,
- Rotary Valve Fed.
A Loss-In-Weight Feeder can be used for:
- Gain-In-Weight,
- Loss-In-Weight
Available Output
A Loss In Weight Feeder will provide:
- The total of the material passing, and
- Instantaneous Flow Rate.
- An analogue output signal can be used to control other equipment.
- RS232, RS422/485 Communications
Pulse Output
The LIW system can also be used for product blending. The analogue output signal acts as a reference to control the addition of one or more additional products.
Loss In Weight Belt Feeder Application
Accuracy
Loss-In-Weight systems are the most accurate of all continuous weighing systems. Expect ± 0.50% or better. For a LIW System to work satisfactorily, the product being handled must have good linear volumetric feed:- from 0 to 100% of the required flow rate.
Flow Rate
Generally LIW feeders are used where lower flow rates are required. The LIW hopper needs to be refilled relatively quickly, as during the refill cycle, it is operating in volumetric mode.
Flow rates up to 50tph can be achieved. |
Loss In Weight Belt Feeder Application
Method of Operation
A Loss-In-Weight system comprises a bin or hopper and a feeder mounted on load cells which measure the whole system and sense the change in weight as material is discharged.
Material can be manually or automatically loaded into the LIW hopper. The controller monitors and controls the weight gravimetrically from the high setpoint to the low setpoint. When the LIW Hopper reaches the low setpoint, the controller switches from gravimetric to volumetric feeding while the LIW Hopper is refilled. The controller changes back to gravimetric weighing after the LIW Hopper is refilled.
Advantages
- Continuous product flow.
- Normally requires only static calibration.
- Most accurate of all continuous weighing methods.
Disadvantages
- Requires more headroom than Weigh Feeders.
Loss In Weight Application
Selection Criteria
To select the correct Loss in Weight system, contact us.
We will need you to provide us with some basic
- What is the application?
- What accuracy is required?
- Flow Rate
- Physical space available
- The upstream feed equipment.
Contact us for a Loss-In-Weight Feeder Questionnaire, complete and return to us. |
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