Electricity and Control July 2021

MEASUREMENT + INSTRUMENTATION : PRODUCTS + SERVICES

Debottlenecking – have you verified the thermowells?

Debottlenecking is helpful for many large operations be- cause the optimisation of existing equipment to achieve small percentage increases in output capacity can result in significant profit returns. Debottlenecking typically entails the reconfiguration of existing process equipment and control loops to in- crease output or product yield without having to increase the size of the plant. It is usually treated as a cost-saving project. In such reconfigurations, process param- eters are often changed to allow for improve- ments and, in turn, require that the operating ranges of measurement instrumentation be re-evaluated; often this equipment is recommissioned. Where they are in use, thermowells, although not classified as measur- ing equipment, are also affected by these changes, as high flow velocities can result in vortex-induced vibration on a thermowell. Best practice indicates that end-users should perform the ASME PTC 19.3 TW – 2016 calcula- tion during a debottlenecking project, and before start- up, to ensure that the thermowell will operate safely with the new process parameters. If the ASME PTC 19.3 TW – 2016 calculation yields a negative result, a change in the dimensions of the ther- mowell is recommended as a first option. Should a di-

The ScrutonWell ® thermowell from WIKA.

mension change not resolve this, support collars can be introduced as a second option, which results in longer down time. This second approach is expensive and not always desirable to the plant operator or end user. With the ScrutonWell ® design from WIKA, no further mechanical enhancements to the existing thermowell installation are required and vortex-induced vibration is almost completely eliminated. As the graph shows, with the ScrutonWell ® thermowell, vortex-induced vibration is almost completely eliminated.

For more information contact WIKA South Africa. Email: sales.za@wika.com, visit: www.wika.co.za

Keeping an eye on flow

Further features of the DAI include: the connection range G1/2”… 3, 1/2” … 3”, NPT, DN 15…DN200, ANSI 1/2” … 8”; maximum pressure of 40 bar; maximum tem- perature of 260°C; and material range of carbon steel, stainless steel, PVC, PP and PVDF.

Kobold’s DAI flow indicator is available from Instrotech. This instrument is suitable for horizontal and vertical installations. It is available in metal or plastic with matching process connections from DN 15 to DN 200. The plastic versions with sight glasses are made of borosilicate glass which can withstand temperatures of up to 260°C.

For more information contact Instrotech. Tel: +27 (0)10 595 1831 Email: sales@instrotech.co.za Visit: www.instrotech.co.za

The KOBOLD DAI flow indicator.

20 Electricity + Control JULY 2021