Orifice plate calculation sheet

The standard value is intended for unified calculation and application; temperature and pressure compensation must be applied during actual measurements.....

This post was last edited by HEJIYUER on 2016-2-25 21:18. Gases with stable composition: NM3 and KG are “equivalent,” as the density remains constant for NM3; for example, 100 NM3 of air is equivalent to 100 x 1.29 = 129 KG. In general, NM3 is used to represent flow rate in utility systems, to facilitate unified evaluation. The differential pressure DP of the orifice plate is generated by the operating flow velocity, and the operating flow velocity = KG/operating density; therefore, the calculation program for the orifice plate must have the operating density entered (or it can be determined automatically by the program). The range of your orifice plate is NM3 (equivalent to KG), but a conversion with a red label must be performed in the background of the calculation program in order to determine the orifice diameter d. If there is a deviation in the actual temperature and pressure, that is, if the operating density changes, then according to the red-text indication, the differential pressure will definitely change, which in turn causes changes in the flow rate readings. Therefore, it is necessary to perform temperature and pressure compensation in order to correct this operating density. @jiaguoyun @Big Horse with a Big Bow

Only the orifice plate flow meter lacks temperature measurement; how can pressure compensation be achieved for remote pressure transmission?

The orifice plate definitely has a pressure point and a temperature point for temperature and pressure compensation~~look carefully~~In production, standard flow rates are generally used; using volumetric flow rates is not conducive to production control and measurement~~

What was said on the 3rd floor is basically correct. When temperature and pressure compensation is needed, use the remote temperature and pressure sensors located on the same pipeline, and have the manufacturer connect them to the temperature and pressure compensation module. Design firms sometimes overlook this; therefore, when checking the manufacturer’s control system before it leaves the factory, make sure that all necessary temperature and pressure compensation measures have been implemented

To test the gas/steam in the plant, we can perform temperature and pressure compensation in order to improve accuracy (by correcting the operating density); these testing flowmeters are generally installed in the plant’s boundary ductwork. As for the flow meters used to measure the flow of materials inside the device, it isn’t necessary to perform temperature and pressure compensation, as the temperature and pressure inside remain relatively stable. Moreover, these flow meters are usually installed for control or monitoring purposes, and the accuracy requirements aren’t very high; it’s sufficient to know the general balance of the materials. If the pressure after actual operation differs significantly from the design value, the approach used on the 6th floor is feasible: find a PT measurement point that is close to it. The temperature of the material generally does not deviate much from the design value; moreover, the compensation formula uses 273 as its base, so it’s unnecessary to apply any compensation.

It’s likely as you said: the requirements for that area are high, with remote transmission of temperature and pressure to enable direct compensation for these parameters. The flow rate within the device area is provided merely to help monitor fluctuations in flow; the temperature and pressure compensation is based on the values specified during design. If there are significant changes, errors may occur in the flow rate measurement within the device area.

That’s exactly it; meters are generally installed at the boundaries, which are the points where materials enter and exit. What we measure is precisely the movement of materials in and out. For the gaseous materials inside the device, there are many factors that can cause changes in density; these are related to the operating conditions (such as changes in the gas composition). Even if the process parameters are not accurate, the reasons can still be identified, so there’s no need to blame the instruments. . . ;P

How is the unit of range, cubic feet, determined on the specifications sheet for flow orifice plates?