The installation quality of plastic tube flowmeter (plastic tube rotor flowmeter) directly affects the measurement accuracy and equipment life. The installation points need to revolve around core aspects such as verticality, straight pipe section, environmental conditions, connection sealing, debugging and maintenance. The following is a detailed explanation:

1、 Vertical installation and fluid direction

Verticality requirement

The plastic tube flowmeter must be strictly installed vertically (inclination angle ≤ 2 °) to ensure that the float can freely rise and fall inside the cone tube. If installed at an angle, the friction between the float and the inner wall of the cone tube increases, resulting in low or stuck measurement values.

Installation method: Use a level or plumb line to calibrate the verticality of the instrument, and avoid forcibly pulling the pipeline when fixing the bracket.

Fluid direction

The fluid must flow from bottom to top (with the inlet at the bottom and the outlet at the top) to stabilize the float in an equilibrium position under the combined effects of pressure difference, gravity, and buoyancy. If installed in reverse, the float cannot rise normally and the measurement fails.

2、 Direct pipe section configuration

Length of front and rear straight pipe sections

To eliminate the effects of eddy currents and uneven velocity distribution in the pipeline, sufficient straight pipe sections should be left in front and behind the instrument:

Front straight pipe section: Length ≥ 5 times the diameter of the pipe (5D), ensuring that a stable flow state is formed before the fluid enters the cone pipe.

Rear straight pipe section: length ≥ 3 times the diameter of the pipeline (3D), reducing the impact of outlet disturbance on the float.

Example: If the diameter of the pipeline is DN50 (D=50mm), the front straight pipe section must be ≥ 250mm, and the rear straight pipe section must be ≥ 150mm.

Special scenario handling

When space is limited: If it is not possible to meet the requirements of the straight pipe section, a rectifier (such as orifice plate or tube bundle) can be installed to improve the flow state, but the model should be selected according to the instrument manufacturer's recommendations.

Installation near elbows or valves: Avoid installing directly after 90 ° elbows, valves, or reducing/expanding pipes upstream of the instrument, otherwise increase the length of the straight pipe section (such as requiring a 10D straight pipe section after the elbow).