Gemue 801
The Gemue 801 is the variable area flowmeter of the 800 series with a PVC float, for liquids in nominal sizes DN 20, DN 25, DN 32, DN 40, DN 50 and DN 65. It measures purely mechanically, without auxiliary power: the float rises in the conical metering tube until flow force and weight are in balance, and its upper edge shows the flow rate directly on the printed scale. PVC is the lightest of the three float materials in this series — which is why, at a given nominal size, it reaches the lowest flow rates. As an authorised dealer we stock 629 versions of this group.
Float and measuring principle
PVC is the lightest of the float materials in this series, and that decides the application: a lighter float rises at a lower flow rate, so this group covers the bottom end of each nominal size. Where the same volume flow is to be measured with a stainless steel float, the Gemue 807 is the place to look. The metering tube size appears as a cone in the type code — 19 sizes from cone 46 to cone 77; together with the nominal size it determines which range is attainable. The reading is taken at the upper edge of the float. This group does not carry the magnet needed for contactless limit detection; the Gemue 811 does.
Scale, unit and medium
The scales in this group are calibrated for three media: water (316 versions), sodium hydroxide (72) and hydrochloric acid (67). Which medium applies is held as a separate attribute on the article — a scale calibrated for water will not read the same on sodium hydroxide, because the density of the medium enters into the float position. On units the group splits: 336 versions are scaled in litres per hour, 93 in cubic metres per hour, 22 carry a percentage scale from 10 to 100 %. The unit is part of the version, not a matter of conversion — to read in m³/h you need a metering tube printed accordingly.
Metering tube, seal and connection
The metering tube comes in three materials: clear PA (246), clear PVC-U (197) and PSU (186). Clear PVC-U and clear PA make the float easy to see, PSU is the mechanically more robust material. Sealing is by O-rings in EPDM (431), FPM (177) and FEP encapsulated (21) — with alkalis and acids this choice is not a detail but the actual selection criterion, because seal and metering tube together determine which medium is permissible. Connection is made via 15 connection types and 10 material combinations for the connection parts; union ends with inserts to DIN form the bulk. In every version the body is a straight through tube.
Where it sits in the 800 series
The 800 series is organised by two features: the float material and whether the float carries a magnet. This 801 is the PVC variant without a magnet; with a magnet it is the Gemue 811. In PP they are the Gemue 805 and Gemue 815, in 1.4571 stainless steel the Gemue 807 and Gemue 817, plus the Gemue 806 with a guided float in DN 65. The material decides the flow range, the magnet decides whether the position can be evaluated — two independent decisions. There is no nominal size below DN 20 in this series; the 850 series starts at DN 10 instead, for example with the Gemue 855. For air rather than liquid the Gemue 875 for air applies, and the accessories are under Gemue accessories for flowmeters. All series at a glance: Gemue brand page.
