HEDLAND
Frequently asked questions
Common questions about HEDLAND from 3G Electric.
What is the operating principle of a Hedland variable-area flowmeter?
Hedland variable-area flowmeters use a tapered metering tube and a float. Fluid enters the tube from the bottom and flows upward, lifting the float. The annular area between the float and the tube increases with height, so the float reaches an equilibrium position where the upward force from the fluid equals the downward force from gravity. The float's position is read against a scale on the tube to indicate flow rate. This design is simple, requires no external power, and provides direct local indication. The meters are typically accurate to ±2% of full scale for liquids. They can be installed in any orientation without affecting accuracy, although vertical installation with flow upward is common. The meters are available with various end connections and seal materials to suit different fluids.
What are the pressure and temperature ratings for Hedland flowmeters?
Pressure and temperature ratings for Hedland flowmeters vary by model and construction. Many standard models are rated for working pressures up to 350 bar (5,000 psi) and temperatures up to 116°C (240°F). However, these limits depend on the body material, seal material, and connection type. For example, meters with Viton seals are suitable for higher temperatures than those with Buna-N seals. Always refer to the specific product datasheet for exact ratings. Operating outside the rated limits can damage the meter and cause inaccurate readings or leakage. When ordering, specify the fluid, pressure, and temperature so that the correct configuration can be supplied. 3G Electric can provide datasheets for all Hedland models in its catalog.
Can Hedland flowmeters be used with water or other non-petroleum fluids?
Yes, Hedland offers flowmeters for water and other non-petroleum fluids. The product line includes models specifically designed for water, as well as models for oils and gases. The choice of model depends on the fluid's compatibility with the wetted materials. Standard wetted materials include aluminum, brass, and stainless steel, with seals in Viton or Buna-N. For water service, stainless steel bodies and Viton seals are often recommended to resist corrosion. The flow range and scale calibration also differ between oil and water models because of viscosity differences. Using an oil meter on water will result in inaccurate readings. Always select a meter that is calibrated for the fluid being measured. 3G Electric stocks a range of Hedland meters for different fluids and can help identify the correct model.
What is the difference between a Hedland flowmeter and a flow switch?
A Hedland flowmeter provides a visual indication of flow rate, while a flow switch provides an electrical output when flow reaches a set point. Flow switches are used for alarm or control functions, such as signaling low flow or activating a pump. Hedland flow switches use the same variable-area principle but include a magnetic coupling that actuates a reed switch or similar device. Some models combine both functions, offering a local scale and an electrical switch. Flow switches are typically specified when remote monitoring or interlock protection is required. They are available in various switch types, including SPDT and DPDT, and with different electrical ratings. The set point is adjustable on many models. For applications requiring continuous flow measurement and transmission, a flow transmitter is used instead. 3G Electric supplies Hedland flow switches and transmitters alongside the mechanical flowmeters.
How do I select the correct Hedland flowmeter for my application?
To select a Hedland flowmeter, first determine the fluid type, flow range, and whether local indication or electrical output is needed. Then consider the operating pressure and temperature, and choose a meter with ratings that exceed these values. Next, select the connection size and type (NPT, SAE, BSP, flanged) that matches your piping. The body and seal materials must be compatible with the fluid. For viscous fluids, a meter with a larger port size may be required to handle the flow without excessive pressure drop. Accuracy requirements and scale units (gpm, lpm, etc.) should also be specified. Hedland offers a wide range of models, and 3G Electric can assist with selection based on your parameters. Providing complete application details will ensure the correct meter is supplied.
Does 3G Electric supply HEDLAND products?
Yes — 3G Electric (S) Pte. Ltd. supplies HEDLAND products. We stock the HEDLAND catalog and supply genuine factory-original products with full manufacturer warranty and technical support.
