Views: 0 Author: Site Editor Publish Time: 2022-07-18 Origin: Site
Stainless steel pressure gauge is composed of pressure guiding system (including joint, spring tube, current limiting screw, etc.), gear transmission mechanism, number display device (pointer and dial) and shell (including watch case, watch cover, watch glass, etc.).
The pressure gauge passes through the elastic deformation of the stainless steel sensitive elements (Bourdon tube, bellows, bellows) in the watch, and then transmits the elastic deformation to the pointer by the conversion mechanism of the movement in the watch, causing the pointer to rotate to display the pressure. For the instrument filled with liquid (usually silicone oil or glycerin) in the shell, it can resist the violent vibration of the working environment and reduce the pulsation effect of the medium pressure.
1. Regarding the selection of the pressure measuring point, the real situation of the measured pressure should be reflected when selecting the pressure measuring point. details as follows:
A. It should be selected in the pipe section where the measured medium flows in a straight line, and should not be selected in the pipeline bends, bifurcations, dead ends or other places where vortices are easily formed.
B. When measuring the pressure of the flowing medium, the pressure point should be perpendicular to the flow direction, and the drilling burr should be removed.
C. When measuring liquid pressure, the pressure-taking point should be at the lower part of the pipeline, so that no gas is accumulated in the pressure-guiding pipe. When measuring gas, the pressure-taking point should be above the pipe, so that no liquid is accumulated in the pressure-guiding pipe.
2. Instructions for use and ordering:
A. The shock-resistant stainless steel pressure gauge is not suitable for the environment of external strengthening agents such as oxygen, nitric acid and oxygen perchloride.
B. When the stainless steel pressure gauge shell needs to be sprayed with PTFE coating, please specify it when ordering.
C. If you need special requirements for the stainless steel pressure gauge joint thread, please specify.
D. All stainless steel pressure gauges are divided into ordinary type and shock-resistant type.
E. Please specify the name, model and upper limit of measurement when ordering.
1. Selection of the position of the pressure port
a. Make the sampling pipe and the flow direction of the medium perpendicular to each other, and avoid the place where the valve, bifurcation and elbow are easy to form vortex;
b. When there is a protruding object in the pipeline, the pressure taking port should be taken in front of it;
c. When measuring the pressure of liquid and water vapor, the pressure point should be set on the lower side wall of the horizontal pipe, so that there is no gas in the pressure pipe, so as to avoid the sediment in the pipe from blocking the sampling nozzle;
d. It is a pressure gauge for measuring liquid and steam media, and is installed at the lower part of the instrument panel to prevent liquid or condensation from dripping onto other instruments.
2. The laying of the pressure pipe
The function of the pressure pipe is to transmit the pressure signal between the pressure point and the pressure gauge. Attention should be paid to its laying: First, the inner diameter of the pressure pipe is usually 6-10mm, and the length is less than 50mm, so as to reduce the measurement error and avoid the pressure caused by the medium lag. The indication of the meter is delayed; the second is that the horizontal section of the connecting pipe should have a certain slope, and the slope should be maintained at 1:10 ~ 1:20 to facilitate the discharge of condensate or gas in the pipe. Isolation valve for use when servicing the pressure gauge.
3. Determination of installation height
The installation height should be suitable for the staff to observe, at the level of the line of sight of ordinary people, that is, 1.5m to 1.6m. For high pressure, it should be higher than the head of ordinary people, that is, about 1.7m to 1.8m. When the vertical distance between the installation position of the pressure gauge and the pressure measuring point is very large, the correction of the liquid column difference should be carried out. The correction value is equal to the pressure value generated by the liquid column in the conduit of the vertical height difference between the instrument and the pressure measuring point. When the meter is higher than the pressure measuring point, add this correction value; on the contrary, when the meter is lower than the pressure measuring point, this value should be subtracted.
4. Use sealing gaskets
In order to ensure tightness, a suitable gasket should be selected for the seal between the joint of the pressure gauge and the gauge seat. When the working temperature and pressure are lower than 80℃ and 2MPa, use leather gaskets or rubber gaskets; at 80℃～45℃, use asbestos paper or aluminum pads below 5MPa; when the working temperature and pressure are higher, use annealed copper pads or lead pad.
5. Use a desander to treat heavy drilling fluid, but a large-size desander with a separation particle size greater than 74 μm must be used. Since the subsidence diameter ratio of barite and drill cuttings is about 1:1.5, a desander that can remove drill cuttings above 74μm can also remove barite powder above 49μm. In barite, this part of the particles accounts for about 10%-15%. The weighted drilling fluid that has been pretreated by the desander enters the mud cleaner, which can greatly reduce the burden of the mud cleaner. The disadvantage is that some barites with larger particle sizes suffer some losses.