F.A.Q. on process weighing

1.  Why should I consider using weight as the key measurement of my process?

2.  What about mass meters?

3.  What are some of the things to consider in selecting a system?

4.  What do I have to worry about during installation?

5.  Why BLH?

Q1:  Why should I consider using weight as the key measurement of my process?

A: Weighing can provide high accuracy batch, level and inventory control without the need to consider the density, temperature or properties of the material. It is non-intrusive, and once installed, it is low maintenance. Many recipes are based on weight rather than volume.

Q2:  What about mass meters?

A: Although suppliers will be supportive of their various technologies, the best solution may be both. Weighing provides the highest level of accuracy based on full scale or rated output, but its accuracy remains the same for any increment. Mass flow meters can provide high accuracy for smaller additions. Weighing systems will allow metering of large quantities at high rate, reducing the cycle time, and allow for simultaneous additions to multiple tanks.

However, if more than one ingredient needs to be added then mass meters would be the most logical choice. For solids, weighing provides the best approach. The bottom line is that resource allocation, cycle time and other operating factors should be considered in selecting the best measurement(s) to use.

Q3:  What are some of the things to consider in selecting a system?

A: There is a tradeoff between cost and accuracy. However, a number of factors related to the actual operation should be considered. Most load cells system will provide superior results when weighing a vessel that does not have piping attached and is not subjected to vibration. Maintaining that accuracy under actual operating conditions of agitation, vessel expansion due to temperature expansion and other loading conditions requires more study.

Other key factors include area classification, earthquake and wind load, interface requirements, and operator interface. The enclosed data sheet will help in organizing some of these considerations.

Q4:  What do I have to worry about during installation?

A: The main objective during installation is to get the weight evenly distributed on the load cells and to allow for adequate expansion so that no rubbing, grabbing etc. occurs during the operation of the vessel. Any piping should provide an even and reproducible “spring” (either by long runs of pipe or expansion joints) that can be removed during the calibration of the system. Protection must be given to the load cells modules from either being over stressed mechanically or damaged by the electrical or heating effects of welding.

Q5:  Why BLH?

A: BLH has worked over many years to make process weighing systems reliable and accurate. In addition, BLH has the hardware, expertise and support to make sure that your system is designed and installed correctly to give you the results you expect. And yes, they offer guarantees!