CONTROL previous Web Poll results
Level With Me: Why do your problem level applications give you fits?
- The application was poorly designed: 34.15%
- The fluid/solid is very hard to measure: 25.61%
- The process upsets are very fast and level changes too quickly: 15.85%
- The measurement technology we use gives bad readings: 14.63%
- The meter is too high-maintenance to keep going: 9.76%
Which level devices give you the most problems?
- Differential pressure (DP) sensors: 25.61%
- Bubbler-type sensors: 18.29%
- Ultrasonic-type sensors: 23.17%
- Mechanical-type: 17.07%
- Radar-type sensors: 4.88%
- Other: 10.98%
- 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.