2350 Industrial Road, Sapulpa, OK 74066 • Main: 918-445-1141 • sales@weamco.com Bulletin MPD-112 Toll Free: 800-331-3790 • Fax: 918-445-4617 • www.weamco.com 5-19 Page 5 of 8 Conventional Liquid Meter Provers Design and Construction E. Detector Switches: Detector switches are used to gate the pulse counter or flow computer. Detector switch repeatability is crucial in determining the prover volume and for consistent meter proving.  The most common switch is a mechanical actuated electrical type, such as our Mag-Tek M-6, which has a plunger inserted into the pipe. The sphere passes under the plunger to raise and make the switch or contact. These switches should be pressured balanced so pressure forces are not a factor. F. Diverter Valve: Bidirectional provers utilize a 4-way diverter valve. This valve is ported to allow flow to enter one launch chamber and exit the opposite, and by cycling the valve the flow direction is reversed. All 4-way valves are designed for speed and seat seal integrity, valves should be equipped with a means of checking the seal for leakage (e.g., block and bleed port, DP gauge or switch) Note: These valves only divert and do not “block” the flow. G.  Diverter Valve Operator: Most diverter valves are equipped with actuators to automate the prover operation. These can be electrical or hydraulic. Electric operators are the most commonly used. All operators are to be self-locking. H Internal Coatings: Internal coatings are applied to the prover for two main purposes: 1.  Protect the pipe from corrosion and pitting which can cause repeatability problems. 2.  Provide a smooth uniform surface for the sphere to travel in, and ensure a good seal with stable movement without surges or jerks. Common types of coating: Air-dried epoxy Baked-on phenolic