Web POLL results: Level with me

Feb. 14, 2005
CONTROL previous Web Poll results

Level With Me: Why do your problem level applications give you fits?

  1. The application was poorly designed:  34.15%
  2. The fluid/solid is very hard to measure:  25.61%
  3. The process upsets are very fast and level changes too quickly:  15.85%
  4. The measurement technology we use gives bad readings:  14.63%
  5. The meter is too high-maintenance to keep going:  9.76%

Which level devices give you the most problems?

  1. Differential pressure (DP) sensors:  25.61%
  2. Bubbler-type sensors:  18.29%
  3. Ultrasonic-type sensors:  23.17%
  4. Mechanical-type:  17.07%
  5. Radar-type sensors:  4.88%
  6. Other:  10.98%
Reader Comments:
  • Most sensors cannot detect foam levels and therefore fail. Once the foam touches the sensors it gives the impression that the tank is always full.
  • Our biggest problems come in startup of the refrigeration system and attempting to regulate the level of refrigerant in the low-pressure receiver. During startup the refrigerant changes state rapidly from liquid to gas resulting in instantaneous changes of 25 in. in a 35-in. tank. We’re finally at the point of simply ignoring the level during startup.
  • We have used displacers and DP transmitters for level for years, with varying results., However, we now preferentially use TDR (GWR) level devices and problems are fewer and measurement more reliable.
  • The LP and HP legs in DP type level measurement systems become empty and we have to manually fill the fluid whose level is to be measured. A special T assembly has also to be made. IF such an application is used in vacuum service then even a slight leakage leads to the emptying of a leg.