Pressure and temperature selection
The actual working pressure of the fluid in the pipeline should be less than the rated working pressure of the flowmeter. Pay attention to whether there is negative pressure in the pipeline, such as the evaporation process, and the negative pressure is up to -60KPa. Such working conditions should be communicated with the manufacturer's technicians when ordering. Strict requirements are imposed on the lining material. The actual temperature should meet the temperature requirements specified by the flowmeter.
Power supply selection
The choice of the electromagnetic flowmeter power supply should be selected according to the flowmeter itself and the environment of the site. If the site allows, the power supply is convenient, safe and easy to maintain. As a chemical company, more than 90% of the raw materials and process links are in the liquid phase. During operation, the internal humidity of the workshop is large, and no flammable gas is generated during the whole operation. It is safer to use DC24V for power supply. Outdoor dry environment, choose AC220V power supply, convenient lead wire, good maintenance and low cost.
Some explosion-proof occasions, such as flowmeters used in gas boilers, are ideal for battery-powered electromagnetic flowmeters.
Turbine flowmeter composition
Turbine flowmeters are speed flowmeters, also known as impeller flowmeters. The impeller type flowmeter utilizes the relationship between the rotational angular velocity of the impeller placed in the fluid and the fluid flow velocity. By measuring the rotational speed of the impeller to reflect the volumetric flow rate of the fluid passing through the pipeline, it is a relatively mature high-accuracy instrument in the flowmeter. One. Turbine flowmeters generally consist of the following five typical parts:
1. Body
The material of the body is generally steel or cast iron, and the ends are flanged. The small diameter gauge also has a threaded interface.
2. Measured component
The turbine has precision machined blades that together with a set of reduction gears and bearings form the measuring assembly. The two high-precision stainless steel permanent self-lubricating bearings that support the turbine ensure a long service life of the assembly. Turbine flowmeters can also be lubricated with an external lubricant pump, but be careful not to overdo it.
3. counter
The following important information is available on the counter panel:
(1) Maximum working temperature and pressure:
(2) Metering and minimum and maximum flow levels
(3) Product model and number
(4) Explosion-proof grades and signs
(5) The equivalent of the fluid corresponding to the low frequency or high frequency pulse and the wiring method.
4. Rectifier
The rectifier is used to keep the fluid flowing through the turbine flow meter in a regular state, thereby eliminating the disturbance and having an unaffected effect on the metering. High metering accuracy.
5. Magnetic coupling transmission device
The device separates the counter portion in the atmospheric environment from the gas being measured and transmits the rotation of the measuring assembly to the counter.
According to different output signals, these products can be divided into LWGY-□N type and LWGY-□A type.
LWGY-□N type sensor: 12～24VDC power supply, three-wire pulse output, high level ≥8V, low level ≤0.8V; signal transmission distance ≤1000m;
LWGY-□A type transmitter: 24VDC power supply, 2-wire 4-20mA output, signal transmission distance ≤1000.
This type of turbine flow products are divided into basic type and explosion-proof type (ExdIIBT6).
2, intelligent integrated turbine flowmeter
Intelligent integrated turbine flowmeter adopts advanced ultra-low-power single-chip microcomputer technology to develop a new intelligent instrument integrating turbine flow sensor and display integration. It adopts double-row liquid crystal field display, with compact structure, intuitive reading and reliability. High, free from external power interference, lightning strike, low cost and other obvious advantages. The instrument has three-point correction of the meter coefficient, the intelligent compensation meter coefficient is nonlinear, and field correction can be performed. The high-definition LCD displays both instantaneous flow (4 significant digits) and cumulative flow (8 significant digits with clear function). All valid data is not lost after 10 years of power failure. These turbine flowmeters are explosion-proof products with an explosion-proof rating of ExdIIBT6.