TOPIC:

"High Performance" Instrument Valves

Anderson Greenwood - AGCO

Many years of Instrument Valve product development and improvement have yielded design features
when combined in one unit provide a true "High Performance" Instrument Valve.
BONNET TECHNOLOGIES
  • Stem threads are rolled (not cut). This prevents galling and lowers operating torque. The work hardening which occurs during the roll threading process makes the rolled threads stronger and smoother. In addition, 316SS stems are chrome plated for additional galling prevention.
  • Teflon® and Grafoil® packing gland is adjustable while valve is in service.
  • Viton® o-ring stem seal with Teflon® back-up ring provides the ultimate low-torque operation.
  • Mirror stem finish burnished to a 16 RMS finish in the packing area enables smooth stem operation and extends packing life.
  • Packing below threads prevents lubricant washout, thread corrosion, and keeps solids from entering the thread area.
  • Safety back seating prevents stem blowout or accidental removal while in operation and provides a metal-to-metal secondary stem seal while in the full open position.
  • A protective dust cap contains stem lubricant and prevents influx of contaminants.
  • Body-to-bonnet seal is metal-to-metal in constant compression below the bonnet threads. Prevents bonnet thread corrosion, eliminates possible tensile breakage of bonnet, and gives a reliable seal point.
  • Bonnet locking pin prevents accidental removal of bonnet while in service.
SEAT TECHNOLOGIES
  • Hand Valves with soft seats have straight-through flow path providing high flow capacity, bi-directional flow, and rodding capabilities. The soft seat provides bubble-tight shut off.
  • Replaceable soft seat allows replacement of the soft seat insert without removing the valve from the line.
  • Valves with metal seats have a rotating stem with free swivel hardened ball-type seat for long service life. The differential hardness between the ball and seat assures bubble-tight shut off.
INSTRUMENT VALVES PER ASME B31.1 POWER PIPING CODE
  • Grafoil® packing gland is adjustable while valve is in service.
  • Bonnet lock prevents accidental loosening of the bonnet-to-body seal. A high-strength short bonnet pin aligns a hex collar over the bonnet. A panel nut then locks the collar against the valve body. The nut allows all instrument valves to be panel-mounted without any additional parts. Tests indicate that the minimum torque required to break the collar loose is greater than the torque required to twist off the valve handle.
  • P & T ratings per ASME B16.34
  • Materials per ASTM specifications
  • Meet ASME Class 2500
  • Hydrostatic testing per MSS-SP-61
  • Valve body markings per MSS-SP-25
 




Natural Gas D.P. Flow Measurement - Best Practices

Minimize Gauge Line Error

Close coupled direct mount systems were developed in response to requests by leading gas transmission companies for a safe, efficient method of close coupling EFM's and transmitters to orifice fittings. The need for close coupling was established through studies conducted by the Southwest Research Institute and sponsored by the Pipeline and Compressor Research Council, which proved the existence of flow and/or pulsation-induced Gauge Line Error (GLE) in traditional, remotely tubed meter installations. The research concluded that GLE can be minimized by mounting metering instruments directly to the orifice fitting, using constant diameter large bore manifolding.

FOR BEST ACCURACY
  • Use 3/8” constant diameter orifice pressure legs of equal length.
  • Distance from orifice tap to measurement instrument should be a maximum of 18".

FOR BEST PERFORMANCE
  • 5-Valve manifold with angled valve bonnet orientation prevents finger pinching.
  • Use multi-turn valve bonnets (not ball valves) to prevent "shocking" the measurement device with a pressure surge.
  • 2-Valve manifold allows for servicing the frequently used 5-valve manifold.
  • Dielectric isolators between stabilized connectors and manifold protect transmitters from cathodic protection currents and possible transient voltage in pipeline.
  • Stabilized connectors provide support for the entire manifold / measurement device installation while transferring the radial stress away from the NPT connections.


Anderson Greenwood
Instrument Valve Catalogs
Description Size
2.1 MB
1.9 MB
6.9 MB
0.8 MB