Petrochemical - Pressure Calibrator, Pressure Test

Transmitters in the petrochemical industry

Chemical industry due to its production continuity, high degree of automation, transmitter is a widely used, one of the many types of instrumentation. Transmitter from the basis of its selection, usually including installation conditions, environmental conditions, instrument performance indicators and measurement media. Of course, the economic indicators is also a very important factor. Generally, large chemical enterprises with strong economic strength often choose high-precision products. Its measurement method also includes direct and indirect two kinds, mainly used for process measurement and production process control, the key number will also be detected by the signal as a device chain control indicators. Its types include: ordinary pressure type, differential pressure type; according to the equipped flange, divided into single-flange type, double-flange type and insertion type.

Transmitter Selection

Basic Transmitter Selection Principles

From the selection of the basis, in order of sequence: (1) the nature of the measured media indicators (2) saving money (3) the use of installation and maintenance.

For high viscosity and easy to crystallize and strong corrosive media, we must choose the isolation type and consider whether the media will cause corrosion of the membrane box metal. In addition, but also based on the measured medium temperature selection. For 200 ~ 400 ℃, to choose high-temperature type. In addition, the working pressure level is also one of the main basis for selection. Should ensure that the pressure level of the transmitter and the application of the conformity of the occasion. Considering the economic factors, the outer membrane box and insertion part, its material must be suitable, the connection flange can be relatively lower requirements to save money. Isolated to threaded connection form is appropriate, can save money and easy to install. Similarly, the general type transmitter selection, should also be considered whether the measured medium has corrosive, but because the general type is to lead the pressure measurement, the medium temperature can not be considered, the disadvantage is that the amount of maintenance is greater than the isolation type. Mainly should do a good job of heat preservation, such as increasing the accompanying heat and heat preservation box, in order to prevent the pressure conduit icing in winter so that the meter can not work or damage.

Differential Pressure Transmitter Selection

Differential pressure transmitters are selected according to the following points:

(i) is to consider the measurement range, the required accuracy of measurement and the measurement function to be achieved.

(B) is to consider the environment in which the instrument is used, whether there are toxic and hazardous gases and flammable gases.

(C) is the nature of the measured medium, such as whether it is a strong acid, strong alkali, whether viscous, whether it is easy to solidify or crystallize, whether it will change.

(D) is the change in operating conditions, such as several important parameters (temperature, pressure, etc.), and sometimes should also be considered to drive and to normal production, the concentration of the two phases of the medium and density changes.

(E) is to consider the actual properties of the object container, such as its structure is complex, shape and size compliance. In addition, whether it can have an impact on its internal equipment accessories and import and export of material orifice.

(F) is to consider the generality of the instrument selection, the main should reduce the specification varieties, saving spare parts.

(G) is to consider the actual process conditions, such as the type of equipment to be measured, the physical and chemical aspects of the nature of the medium, cleanliness and so on. Tanks, tanks and troughs, for example, its volume is small, so the measurement range will not be too wide; on the contrary, the tank volume is larger, the measurement range will be correspondingly large, such as the medium’s suspension of more than one, there are bubbles, etc., generally to the selection of single-flange differential pressure transmitter is appropriate. For easy precipitation production is easy to crystallize, it should be inserted double-flange type. And then to high-viscosity media, for example, to measure its level, more than considering the inability to open the hole (such as high-pressure equipment), more than the use of radiation level meter.

(H) is the economy should meet the actual situation, this should be the main consideration of the overall shall not break through the total investment plan, at the same time, should be as far as possible to make the selection of instrumentation type less, to enhance its versatility, and maximize the avoidance of duplication of investment and blind investment.