A range of vortex flowmeters for non-corrosive fluids are available from Randburg-based flow specialists C&F Technologies. Designated the Coolpoint series, the range consists of an in-line flowmeter that utilises the vortex shedding principle to measure the flow of non-corrosive liquids. In a vortex flowmeter, the fluid flows around a bluff body, generating vortices (eddies) that move downstream. The vortices form alternately, from one side to the other and are sensed by a piezoelectric sensor housed in a sensor tube mounted directly downstream of the bluff body and which picks up the pressure zones created by the vortices. The piezoelectric sensor generates a frequency that is directly proportional to the vortices created by the fluid flowing past the bluff body and which are themselves proportional to flow. The sensor output is then amplified by the electronics to give an indication of flow rate as well as a 4-20 mA output for remote monitoring and control purposes. Flow is displayed in either GPM or LPM units on an LED display and solid-state relays are included should an alarm or pulse output (for totalising) be required. The solid-state relays can be set over the range from 15% to 90% of full-scale flow and can also be configured to be either NC (normally-closed) or NO (normally open), or pulse.
Coolpoint vortex flowmeters can be used on low viscosity, clean or dirty water-like liquids that are compatible with brass, PVDF and viton. Metered fluids should not include long fibres or a significant level of abrasive solids. However, should abrasive wear of the bluff body take place over time, the bluff body, as well as the sensor, are replaceable. Typical applications include cooling applications using water, 50% solutions of glycol, and water soluble machine coolant (up to 10%). These applications are found in most process industries, such as rubber, steel, fabrication, manufacturing, refining, paper, chemical, food, petrochemical, mining and power. The Coolpoint is not designed for use with gases or air, or for use with flammable liquids.
For best results, the Coolpoint vortex flowmeter may be installed in any position as long as proper piping installation requirements are observed. This includes sufficient support of adjacent piping to minimise any system vibration that might otherwise cause errors. It is also recommended that unions of the same pipe size, together with full-port isolation ball valves be installed for ease of removal and servicing of the flowmeter if necessary. In order to achieve the stated accuracy (±2,0% for 1/4" to 1/2" sizes and 1,0% for 1/4" to 4" sizes) the Coolpoint should be installed in a straight pipe-run of at least 10 pipe-diameters upstream of the meter and with at least five pipe-diameters of straight pipe downstream. Throttle valves, if they are used, should always be installed downstream of the flowmeter and in order to ensure the proper development of vortices the system should have a minimum back-pressure on the flowmeter of at least 10 psi (70 kPa).
Manufactured by Universal Flow Monitors of the USA, the Coolpoint range of vortex flowmeters were originally designed for HVAC cooling circuit applications but have since found ready use in a great many industrial applications where low-cost flow measurement was also required. Although the standard offering is a brass body version with PVDF sensor and viton seals in all sizes from 1/4" to 4" (6 to 102 mm), the Coolpoint units are also available in SS body with kalrez seals in the 1/4" and 1/2" (6 and 13 mm) sizes. Connections are either NPT or BSP in all sizes up to 2" (51 mm), with the 3" and 4" (76 and 102 mm) units being flanged to ANSI 150#. Being manufactured in sizes down to 1/4" (6 mm) makes the Coolpoint rather unique in that most manufacturers do not generally offer a vortex flowmeter in sizes smaller than a 1" (25 mm) meter size. This makes the Coolpoint very attractive for those applications where a low cost flow transmitter is an essential requirement.
An enhancement of the Coolpoint is the Calpoint, a vortex flowmeter incorporating a temperature sensor and temperature transmitter, as well as the flow transmitter, in the one flow device. This makes it very useful and well priced for those applications where both flow and temperature need to be monitored. Both the analog outputs are 4-20 mA and alarm/pulse outputs are solid-state relay as before. The flow units require a separate 24 V d.c. power supply, with the Coolpoint being a 5-wire device and the Calpoint being an 8-wire device if all the functions are utilised in each model.
For more information contact J Gill, C&F Technologies, +27 (0) 11 792 4588.
| Tel: | +27 11 792 4588 |
| Fax: | +27 11 792 8494 |
| Email: | [email protected] |
| www: | www.flowmeters.co.za |
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