Pipeline conditions, installation and use requirements for standard throttling devices

Pipeline conditions, installation and use requirements for standard throttling devices

The throttling device is an entire device including a throttling device, a pressure taking device, and a front and a rear measuring tube. When the fluid filled with the pipe flows through the throttling device, a pressure difference is generated before and after the throttling device, and the differential pressure signal is transmitted to the differential pressure gauge through the pressure device to detect the flow rate.

Since the flow coefficient of the standard throttle device is obtained through experiments under certain conditions. Therefore, in addition to strict regulations on the throttling device and the pressure-receiving device, there are strict rules on piping, installation, and use conditions. If the actual work deviates from the specified conditions, the resulting flow error is difficult to estimate.

1. Pipeline conditions (1) The pipe used to install the throttle should be straight and round.

(2) The inner wall of the pipeline can be smooth or rough, but it must be clean and should not contain impurities.

(3) The length of the straight pipe must be long enough before and after the throttle. However, there are often local resistances such as turns, bifurcations, convergences, and gates on industrial pipelines. The original steady flow of the flow through these resistances will be severely disturbed, and then it will recover after a relatively long pipe section. smooth. Therefore, according to different conditions of local resistance, different lengths of straight pipe sections are placed before and after the throttle.

2. Installation requirements (1) The installation of the throttling element in the pipeline shall ensure that the front surface of the throttling element is perpendicular to the axis of the pipeline. The verticality shall not exceed ±1°. At the same time, it shall ensure that the opening is concentric with the pipeline.

(2) Gaskets for clamping the throttling element (including gaskets between flanges and flanges, annular flanges and pressure-reducing flanges and orifice plates), shall not be clamped Draw into the inner wall of the pipe. The gasket should not be too thick, preferably not more than 0.5mm.

(3) The newly installed piping system must be installed after the piping is flushed and cleaned.

(4) Valves that are used to regulate flow are preferably installed outside the minimum straight section after the throttle.

(5) There must be no abrupt changes in the diameter of the pipe joints of the throttling device.

3. Use Requirements When the standard throttling device is in use, the following conditions must be satisfied: (1) The fluid must be filled with a circular tube and a throttling device and continuously flow through the tube.

(2) The fluid must be a Newtonian fluid that is physically and thermally homogeneous, single-phase, or can be considered single-phase, including gases, solutions.

(3) No phase change occurs when the fluid flows through the throttle.

(4) Fluid flow does not change with time or changes slowly.

(5) Before the fluid flows through the throttle, its flow must be parallel to the axis of the pipeline, and no rotational flow is allowed.

Throttle devices come in a wide variety of forms. Changzhou Chengfeng has the most commonly used throttling devices in actual production, namely standard orifice plates, standard nozzles, and standard venturi tubes. In this article, to all flow meter manufacturers and users, Changzhou Chengfeng Flow Meter Co., Ltd., in its own development, also hopes that all industry colleagues, especially flow meter users, can really buy products that suit their needs. Maintain the product well.

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