Last updateFri, 07 Dec 2018 3pm



Criticality of Torque and Load in Bolted Joints

bolting headline“No matter how big and complex the machinery gets," said John Gans during his presentation at the November 2012 Valve Repair Council Repair Meeting & Exhibition in Houston, "at its heart, holding everything together, is the humble little bolt."

Dr. Gans repeatedly stressed the importance of having well-trained personnel conducting the critical function of bolting, and provided a comprehensive overview of material normally provided in a full one-day course.

Installed Gain and Control Valve Selection

Monsen headshot 330pxJon F. Monsen, Ph.D., P.E., is a control valve technology specialist, with more than 30 years' experience. He has lectured nationally and internationally on the subjects of control valve application and sizing, and is the author of the chapter on "Computerized Control Valve Sizing" in the ISA Practical Guides book on Control Valves.

What Makes Up a Servo Valve Feedback Mechanism is Mission Critical

ColorWheelfigure1To maximize machine operation and business results, engineers ought to consider more than how a servo valve performs with regard to flow/pressure gain, frequency response, and precision. The servo valve, in part, consists of a torque motor, flapper, spool and feedback mechanism. The feedback mechanism can last well above 1 billion cycles. But this lifespan is only achievable with the right selection of materials, manufacturing techniques and mechanical designs.

Measuring Stem Nut Wear Using the SNAP Process

snap testing a 15-foot sluice gate valve stem nut

A motor-operated valve (MOV) stem nut typically is made of a bronze alloy material. During a period of time, stem nut threads wear from opening and closing the valve. Since the valve stem is made of stainless or carbon steel, thread wear typically occurs on stem nut threads.

Ready for Low-E Valve Technology?


With an estimated 60% of fugitive emissions attributed to valves it is easy to see EPA’s attention is on valve emissions reduction. Traditionally valve stem leakage was a visible event. Improvements in packing materials and design lead to non-visibly leaking valves.

In today’s world, government regulations drive measurement of valve leakage to the molecular level in parts per million (ppm). These extremely low vaporous emissions required packing manufacturers to evaluate their product performance to the latest EPA standards for Low E Valve Packing Technology.


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