How to better install instrumentation valves?

The instrument valve has a wide range of applications and is one of the common equipment in automation control in petrochemical, environmental protection, building materials, food, power, metallurgy, light industry, municipal and national defense industries. Relevant matters that need attention during the installation of the instrument regarding its selection and troubleshooting. Engineering instrument installation involves the detection of temperature, pressure, flow, material level, process analysis and data display, automatic adjustment and control. To ensure the normal display and performance of the above functions, installation is the key. Let's talk about it in detail below.

Precautions before installation

1. Before the instrument is installed, the process pipeline should be purged to prevent the ferromagnetic substances in the pipeline from adhering to the instrument, which will affect the performance of the instrument and even damage the instrument.

2. Before the instrument is installed in the process pipeline, it should be inspected for damage, and the housing should be opened to remove the filling of the fixed pointer.

3. The installation form of the instrument valve is divided into vertical installation and horizontal installation. If it is a vertical installation form, the angle between the center vertical line of the instrument and the plumb line should be less than 2 °; the latter installation form should ensure the horizontal centerline and horizontal line of the instrument. The included angle is less than 2 °.

4. The upstream and downstream piping of the meter should be the same as the diameter of the meter. The connecting flange or thread should match the flange and thread of the meter. The length of the upstream straight pipe section of the meter should be 5 times the nominal diameter of the meter. The length of the downstream straight pipe section is greater than or equal to 250mm.

5. Because the instrument transmits signals through magnetic coupling, in order to ensure the performance of the instrument, at least 10cm around the installation, no ferromagnetic substances are allowed to exist.

6. The instrument for measuring gas is calibrated under a specific pressure. If this is the case, a valve should be installed at the meter outlet.

7. The instrument valve installed in the pipeline should not be affected by stress. The inlet and outlet of the instrument should be supported by appropriate pipelines, which can make the instrument in the minimum stress state.

8. Be careful when installing PTFE (polytetrafluoroethylene) lined meters. Since the PTFE will be deformed under the pressure, do not overtighten the flange nut.

9. For instruments with liquid crystal display, try to avoid direct sunlight on the display during installation to reduce the life of the liquid crystal.

10. When measuring in low temperature media, jacket type should be selected.

Cautions during installation

1. The opening of the meter should avoid opening holes in the formed pipes. Note the length of the straight pipe sections before and after the flowmeter. If there are electromagnetic, mass and other flowmeters required for grounding, they should be grounded according to the instructions.

2. When welding process pipes, the ground wire should avoid the meter body to prevent grounding current from flowing through the meter body to ground and damaging the meter. During process welding, avoid ground current flowing through the capillary of the single or double flanged instrument.

3. For medium and high pressure impulse pipes, argon arc welding or socket welding shall be adopted, and argon arc welding or socket welding shall be adopted. Wind speed is > 2m / s, there should be windproof measures, otherwise a covered wire should be used, wind speed is > 8m / s, there must be windproof measures, otherwise welding should be stopped.

4. Pay attention to the installation direction of the pressure taking port of the flow meter throttling device. Stainless steel impulse pipe is strictly forbidden from being heated; flattening of the impulse pipe is strictly prohibited.

Other considerations

Brass pipe connection shall be socket welding, bushing welding or snap-fitting, aluminum pipe shall be sleeve welding, and oxide layer shall be removed before welding. In addition, when the measuring pipeline is connected to the measuring instrument, special attention should be paid. Pipelines for gaseous media and low-boiling-point liquid fluids should be laid up; pipelines for general liquids should also be laid up.

Keep in mind the installation precautions of these valves to better ensure the normal display and function of the above functions.