This meter tube, also called integrated meter tube, is designed for measurement of low flow of fluids in piping with inner diameter lower than 50 mm. The meter tube is a complete set consisting of the centric orifice plate and straight lengths of piping on the inlet and outlet. The meter tube design is divided into three sections: inlet, in which the flown fluid is straightened, measuring section (orifice plate) and outlet.

Straight lengths of piping in the meter tube comply with all conditions on dimensional and geometric accuracy defined by ISO 5167 and ISO/TR 15377 standards that are related to pipe sections attached to the orifice plate. This layout guarantees entrance of stabilized fluid flow into the primary element and accurate measurement of flow rate. Conception of meter tubes also minimizes nonconformities during orifice plate assembly and its subsequent operation. Division of meter tubes to individual sections also enables easier maintenance control or subsequent verification of the meter.

There is corner differential pressure tapping and it is incorporated in the body of flanges, between which the plate is placed, centred and sealed. The pressure tapping is led out of the flanges. Upon agreement with the customers, outlets of differential pressure are always customized to various options of primary element attachment to the measuring circuit. Design of the meter tube enables direct assembly of differential pressure sensor to the orifice plate tapping.

Use of the centric orifice plate in the range of nominal diameter of DN 15 up to DN 50 is limited by β, the orifice plate is manufactured for β = d/D = 0.23 up to 0.7.

The meter tube with centric orifice plate of inside diameter DN 15 up to DN 50 is manufactured with straight lengths of piping minimal 10D “downstream” the orifice plate and 5D “upstream” it.

Process connection of the meter tube is ensured by a flange on both ends as a standard, upon agreement with the customers it can be ended by preparation for weld. Design of the meter tube enables direct assembly of differential pressure sensor to the orifice plate tapping.

Carbon, stainless or refractory alloyed steel are the most used steels for the production of meter tubes. The disc of the centric orifice plate is made of stainless steel as a standard. Upon agreement the meter tube can be manufactured of plastic materials, too.

Meter tube with centric orifice plate for pipelines of inner diameter lower than 25 mm is manufactured as a working meter and for pipelines of inner diameter from 25 to 50 mm it is manufactured as a working or verified meter with metrological verification while observing technical specifications and conditions stated in relevant pattern approval.

On agreement, the meter tube with centric orifice plate for pipelines with inner diameter lower than 50 mm can be manufactured with extended straight lengths of piping, too. The meter tube can be incorporated both in vertical and in horizontal piping.