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| Accuracy |
| By-pass Varea-Meters are accurate to within 4% of full scale when main-line orifice installation conforms to ASME or AGA procedures and by-pass piping follows US Filter/Wallace & Tiernan Products recommendations. |
| Easy, Inexpensive Installation |
| Wallace & Tiernan Products By-pass Varea-Meters are shipped ready to install with the orifice in place. No mercurial or bellows-type manometer is required. Checking or snubbing devices can be omitted, as overranging is harmless. When the metal-tube meter’s float is at rest, float extensions do not project beyond the flanges. Installation is easy. |
| Reliable Metal-Tube Metering |
| The metal-tube meter’s float design discourages attraction of magnetic particles. A dry snubber gives reliable gas measurement down to atmospheric pressure without dashpots or offset piping. A powerful magnetic coupling between the float magnet and the follower magnet in the indicator unit and instrumentation makes for reliable indication, flow switching and transmis-sion. The indicator unit is in a gasketed aluminum housing (NEMA 4X) and has a readable 6-inch percent scale. Other scale calibrations are optional. |
| Flow Switch Available |
| This optional, magnetically coupled switch for the metal-tube meter gives reliable high and/or low flow switching. It is easily set to open or close on increasing or decreasing flow, is compact and easily mounted on the meter. Available in a general purpose or a UL listed hazardous-location arrangement. |
| Reliable Flow Rate Transmission |
| The metal-tube meter offers an optional electronic transmitter. The transmit-ter is a low energy, high output load device. When used with an approved energy-limiting barrier, it is Factory Mutual approved as intrinsically safe in hazardous locations*. Position of the pointer and cam is achieved by a powerful magnetic linkage to the float. The cam has a captive follower, which positions the mechanical arm of a differential capacitance bridge sensor. Any change in the bridge causes a proportional change in the transmitter’s 4-20mA output and in the bridge feedback voltage. The change in feedback voltage is used to rebalance the bridge. Zero and span adjustments are included.
For stand-by operation, the transmitter is easily connected to operate from a battery system.
A gasketed NEMA 4 enclosure protects the mechanism outdoors or in a dusty or corrosive atmosphere. |
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