variable area flow meter types
Common ones may include plastic tube variable area flow meters, glass tube variable area flow meters and metal rotor flow meters. This is distinguished by material. In fact, variable area flow meters can be divided into different categories according to different classification standards. The following content is for your reference.
Glass Tube Rotameter:
The most commonly used material for transparent conical tubes is glass. If the instrument without a guide structure is used to measure gas if it is not handled carefully, the glass tube can be easily broken;
Plastic tube rotor flow meter:
It is also made of transparent engineering plastics such as polystyrene, polycarbonate, plexiglass, etc., which has the advantage of not being easily broken.
Metal Tube Rotameter:
Compared with the transparent conical tube rotameter, it can be used at higher medium temperatures and pressures, and there is no potential danger of the cone tube of the glass tube rotameter being broken.
Local indication type rotameter
Some transparent tube rotor flowmeters mainly provide local indication. Equipped with a proximity switch for upper and lower flow limit alarm signal output.
Some local indication metal tube rotor flowmeters have the same appearance as remote signal output. It only transmits the rotor displacement through magnetic coupling, and then indicates it locally after being processed by linearization mechanisms such as connecting rod cams.
Remote signal output rotor flowmeter
The conversion part of the remote signal output type instrument converts the rotor displacement into current or air pressure analog signal output. They are respectively called electric remote rotor flowmeter and gas remote rotor flowmeter.
There are three types: liquid, gas and steam.
In fact, most rotameter flowmeters can be used for liquids and gases in the same instrument, and their structures are universal.
It’s just that my country’s rotameter industry standards (such as JB/T 6844-93) stipulate that the upper flow rate Qmax must meet the requirements of (1, 1.6, 2.5, 4 or 6) × 10nL/h (n is a positive or negative integer or zero). When the instrument designed for liquid (represented by water) is used for gas (represented by air), it does not meet the above requirements. The float and cone can only be designed separately for gas, which is divided into two series: liquid and gas.
To measure steam, you can only use a specially designed metal tube rotameter or add additional components to the standard instrument. For example, add a liquid damping component with a heat sink to reduce the float jump. The connection with the indication conversion part is separated by a heat sink.
Full flow type: that is, an instrument in which all the measured fluid flows through the rotameter.
Split flow type: Compared with the full flow type, only part of the measured fluid flows through the flow detection part such as the rotor. The split-flow rotameter is composed of a standard orifice plate (or velocity-average tube) on the main pipeline and a smaller-diameter float flowmeter. It is suitable for larger flow rates with a pipe diameter greater than 50mm and in places where local indication is required. It is low-priced. Split-flow rotameter is divided into two types: separate type and integrated type.
