Selection of steam flow meters

The a+k balanced flowmeter is used, and the differential pressure transmitter is from Rosemount

Vortex flow meter with integrated temperature and pressure compensation. Insertion-type vortex flow meters are easy to install and offer good cost-performance, but their accuracy is closely related to the installation position and insertion depth; therefore, they are not recommended for use. Domestic brand manufacturers that offer flange-mounted fittings can achieve DN500

Currently, there are mainly two categories of flow meters used for measuring steam flow: one is the differential pressure type of flow meters, which includes orifice plates, multi-orifice plates (also known as balanced orifice plates), venturi tubes, elbows, nozzles, and Venturi devices. Another one is the vortex flow meter. Both types of flowmeters have their advantages and disadvantages; it is best to choose one based on the on-site process conditions and the accuracy requirements for measurement. Careful consideration should be given when choosing vortex flowmeters, as the quality of these devices varies greatly among different brands; in particular, domestic vortex flowmeters tend to have problems when used for measuring steam flow. It is not recommended to purchase products from small manufacturers or lesser-known brands; one should be especially cautious when it comes to low-priced products. After all, product quality is directly proportional to price – stop believing in the myth that high quality can come at a low cost.

There are only 4 types suitable for measuring steam flow, namely the HK-LGB throttle device (orifice plate), HKGB vortex flow meter, average velocity tube flow meter, and split-rotor steam flow meter. 1. HKLG throttling device (orifice plate): This is a traditional type of throttling device (orifice plate) that is widely used in industrial enterprises. Its advantages include its suitability for various gases, liquids, or vapors that are in a uniform state and at a single temperature; it operates over a wide temperature range and meets the requirements for industrial steam measurement (with pipe diameters greater than 50 mm). There are many domestic manufacturers of the differential pressure transmitters used with this device, making it easy to obtain them as accessories. However, its installation requires significant effort and meets high standards; it needs regular maintenance. Its measurement range is narrow (1:3), it causes substantial pressure loss, and its scale is nonlinear. In particular, it is necessary to regularly calibrate the differential pressure transmitters to ensure accurate zero readings, as well as to check the sampling valves frequently to prevent blockages that could lead to inaccurate measurements. 2. HKGB vortex flowmeter: The vortex flowmeter is a new type of measuring device that began to be produced in large quantities in China starting from the 1980s. Its advantages include a wide range of flow measurement capabilities, a high flow ratio (up to 1:20), and the ability to maintain high measurement accuracy within its operating range without the need for precise calculations regarding the flow rate of the fluid inside the pipe. Since it has no moving parts in its measuring mechanism, it operates reliably, has a long service life, requires little maintenance, and causes low pressure losses (only 1/5 of those of orifice plate flowmeters). This makes it particularly suitable for measuring low flow rates; the minimum pipe diameter is 25 mm. It can be used for measuring both domestic and industrial steam. Since measurement is carried out based on the principle of vortex street generation (self-excited oscillation), it is sensitive to vibrations; therefore, seismic protection measures must be taken near the vortex street generator. High requirements are placed on the selection of installation location, pipeline layout, and surrounding environmental conditions, in order to ensure that the vortex street signals are indeed generated by steam flow. Given the current level of material technology and production capabilities in our country, the temperature of the fluid to be measured should not exceed 400°C; it is generally more appropriate to keep it below 300°C (with no restrictions on pressure). Vortex flowmeters can be said to be particularly suitable for measuring steam flow in centralized heating systems and for end-users in industrial settings. They are widely used in the Jiaxing area, having been adopted by over 100 enterprises that utilize heat networks, including Jiaxing Thermal Power Plant, Jiashan Power Plant, Jiashan Xielian Thermal Power Co., Ltd., and Pinghu Jingxing Group Company – with excellent results achieved in their use. 3. Vortex flow meter: Also known as an Anemometer flow meter, this type of flow meter converts the average velocity within the measuring tube into a flow rate. It is mainly suitable for applications with large pipe diameters, high flow rates, and stable flow velocities. It features a simple structure, easy installation and maintenance, and low costs. Due to its structural characteristics, it produces a low differential pressure, has low sensitivity, and a narrow measurement range (1:3), which makes it unsuitable for applications requiring high measurement accuracy. It is generally used for internal assessments within companies and cannot be utilized for trade settlements.

It is recommended to use the HKGB series of steam vortex flow meters

For vortex flowmeters, we use those from Anhui Tiankang; they’re quite good

For steam flow measurement, the most commonly used are vortex flow meters with pressure stabilization compensation, or those with only temperature compensation or pressure compensation.