Meter tube is a complete set consisting of the multi-hole orifice plate and straight lengths of piping on its inlet and outlet. Design of the meter tube is divided into three parts: inlet, in which fluid flow is straightened, measuring part (orifice plate) and outlet.

Straight lengths of piping in the meter tube comply with all conditions of dimensional and geometric accuracy defined by ISO 5167 standard that are related to the pipe sections adjoining 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 assembly of orifice plates and their subsequent operation. Division of meter tubes into individual sections also enables easier maintenance inspections or subsequent verification of the meter.

There are corner differential pressure tapping. These are 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 metering circuit. Set of the meter tube contains stainless steel expander bolts that greatly facilitate dismantling and subsequent assembly of the disc.

Use of multi-hole orifice plate is limited by β = d/D, the orifice plate is made for β = 0.4 up to 0.65. Meter tube with multi-hole orifice plate is manufactured for nominal diameters ranging from DN 25 up to DN 1,000.

The meter tube with multi-bore orifice plate is manufactured with straight pipe lengths 2D “upstream” the orifice plate and 2D “downstream”. The section 2D “downstream” the orifice plate is finished with a weld. Upon agreement with customers it can be supplied with a flange and a counter-flange, fasteners and sealing.

The meter tube can be equipped with a section complementing entrance section “upstream” the orifice plate to complete length of 4D or 8D depending on the type of fittings upstream the orifice plate. For attachment to the pipeline this section is finished with a preparation to weld.

For the production of meter tubes there are mostly used carbon steel, stainless or refractory alloyed steel. Disc of the multi-hole orifice plate is made of stainless steel as a standard. Upon agreement the meter tube can be made of plastic materials, too.

Multi-hole orifice plate is manufactured either as a working meter or, as a specified meter with metrological verification complying with the technical particulars and conditions of pattern approval.

Except for advantages of centric orifice plates (such as simplicity, replaceability and reliability), multi-hole orifice plates also have the advantage of smaller installation length enabling wider possibilities of their use. Passage of the measured fluid through several tapered cross-section reduces demand on minimal straight lengths of piping downstream and upstream the orifice plate necessary for proper functioning of this type of meter.

Multi-hole orifice plate can be incorporated both in vertical and horizontal piping.