flow measurement method and instrument selection of metal rotameter
Author: PhilemonTime: 2020-11-27
Float tube flowmeter, also known as rotameter, is a kind of variable area flowmeter. In a vertical cone tube that expands from bottom to top, the gravity of a float with a circular cross section is received by liquid power, and the float can move in Rise and fall freely in the cone tube. It moves up and down under the action of flow velocity and buoyancy, and after being balanced with the weight of the float, it passes through the magnetic coupling to indicate the flow with the dial. Generally divided into glass and metal rotameter. Metal rotor flowmeters are commonly used in the industry. For small diameter corrosive media, glass is usually used. Due to the fragility of glass material, the key control point is also a rotor flowmeter made of precious metals such as titanium.
Rotameter is the most commonly used flowmeter in industry and laboratories. It has the characteristics of simple structure, intuitive, low pressure loss, easy maintenance and so on. Rotameter is suitable for measuring small flow through pipe diameter D<150mm, and it can also measure the flow of corrosive medium. The flowmeter must be installed on a pipe section that runs vertically or horizontally.
In order to prevent the rotor from touching the tube wall when moving up and down on the center line of the tapered tube, two methods are usually adopted: one is to install a guide mandrel in the center of the rotor to keep the rotor moving up and down on the center line of the tapered tube. Movement, the other is to have a chute on the edge of the rotor disc. When the fluid flows through the rotor from bottom to top, one side bypasses the rotor and at the same time passes through the chute to generate a reverse thrust, so that the rotor does not stop around the centerline. Rotate to ensure that the rotor does not touch the tube wall during operation. The rotor material of the rotameter can be made of stainless steel, aluminum, bronze, etc.
The working principle of the rotameter and the float flowmeter is the same, but the knowledge is different. Float flowmeter, also known as rotameter, is a kind of variable area flowmeter. In a vertical cone tube that expands from bottom to top, the gravity of the float with circular cross section is borne by the hydrodynamic force. The cone tube rises and falls freely. It moves up and down under the action of flow velocity and buoyancy, and after balancing with the weight of the float, it is transmitted to the dial to indicate the flow rate through magnetic coupling.