Monday, February 19, 2018

Don't Overlook the Importance of Scheduled Calibration for Your Plant's Process Instrumentation

Calibration Process Instrumentation
Calibration is an essential part of keeping process measurement instrumentation delivering reliable and actionable information. All instruments utilized in process control are dependent on variables which translate from input to output. Calibration ensures the instrument is properly detecting and processing the input so that the output accurately represents a process condition. Typically, calibration involves the technician simulating an environmental condition and applying it to the measurement instrument. An input with a known quantity is introduced to the instrument, at which point the technician observes how the instrument responds, comparing instrument output to the known input signal.

Even if instruments are designed to withstand harsh physical conditions and last for long periods of time, routine calibration as defined by manufacturer, industry, and operator standards is necessary to periodically validate measurement performance. Information provided by measurement instruments is used for process control and decision making, so a difference between an instruments output signal and the actual process condition can impact process output or facility overall performance and safety.

Calibration Process InstrumentationIn all cases, the operation of a measurement instrument should be referenced, or traceable, to a universally recognized and verified measurement standard. Maintaining the reference path between a field instrument and a recognized physical standard requires careful attention to detail and uncompromising adherence to procedure.

Instrument ranging is where a certain range of simulated input conditions are applied to an instrument and verifying that the relationship between input and output stays within a specified tolerance across the entire range of input values. Calibration and ranging differ in that calibration focuses more on whether or not the instrument is sensing the input variable accurately, whereas ranging focuses more on the instruments input and output. The difference is important to note because re-ranging and re-calibration are distinct procedures.

In order to calibrate an instrument correctly, a reference point is necessary. In some cases, the reference point can be produced by a portable instrument, allowing in-place calibration of a transmitter or sensor. In other cases, precisely manufactured or engineered standards exist that can be used for bench calibration. Documentation of each operation, verifying that proper procedure was followed and calibration values recorded, should be maintained on file for inspection.

As measurement instruments age, they are more susceptible to declination in stability. Any time maintenance is performed, calibration should be a required step since the calibration parameters are sourced from pre-set calibration data which allows for all the instruments in a system to function as a process control unit.

Typical calibration timetables vary depending on specifics related to equipment and use. Generally, calibration is performed at predetermined time intervals, with notable changes in instrument performance also being a reliable indicator for when an instrument may need a tune-up. A typical type of recalibration regarding the use of analog and smart instruments is the zero and span adjustment, where the zero and span values define the instruments specific range. Accuracy at specific input value points may also be included, if deemed significant.

The management of calibration and maintenance operations for process measurement instrumentation is a significant factor in facility and process operation. It can be performed with properly trained and equipped in-house personnel, or with the engagement of subcontractors. Calibration operations can be a significant cost center, with benefits accruing from increases in efficiency gained through the use of better calibration instrumentation that reduces task time.

Friday, February 9, 2018

Conval Clampseal Valve Inspection Instructions

Inspection of the Conval Clampseal valve.

Conval Clampseal® Valves are much easier to renew than anything else on the market. This video is second of a series demonstrating how to service Clampseal valves.

https://psi-team.com
800-223-1468

Wednesday, January 31, 2018

Conval Clampseal Valve Disassembly Instructions

Conval Clampseal® Valves are much easier to renew than anything else on the market. This video is one of a series demonstrating how to service Clampseal valves.

https://psi-team.com
800-223-1468

Tuesday, January 30, 2018

Understanding How Control Valves Work

Control valveUnderstanding industrial control valve design and operation is very important if you work as a process engineer, a plant maintenance person, or if you design process control loops.

Control valves are used extensively in power plants, pulp and paper mills, chemical manufacturing, petro-chemical processing, HVAC and steam distribution systems.

There are many types, manufacturers, body styles, and specialized features, but the they all share some basics operating principles. The video below explains components, operation, and fundamentals.


Piping Specialties / PSI Controls
800-223-1468
https://www.psi-team.com

Monday, January 22, 2018

Top 3 Reasons to Specify the Conval Clampseal Gate and Globe Valves

  1. Superior Rugged ConstructionConval valves are designed and built for extreme longevity. Features such as electroless nickel plated finish, complete material traceability of all wetted parts and yoke, instantly establish the quality of the Clampseal® Valve. The Clampseal® also has a pressure actuated backseat which provides maximum valve integrity by ensuring a positive internal stop for the valve stem and disc assembly. The actuated backseat extends packing life by securely isolating the packing from the pressure when the valve is fully open. Valves built forty years ago are still in service today.
  2. In-Line Renewability - When inspection or servicing is required, Conval's in-line renewable valves do not need to be cut out (as do most other welded-in valves). The result is the shortest downtime and lowest life-cycle costs in the industry. A complete service, including a reground seat, new packing or stem replacement can often be accomplished in less than thirty minutes.
  3. Renewal vs. Replacement - Renewing Clampseal® valves cost as little as 10% of the cost of replacing it. Renewing the packing is less than 4% of the cost of materials to replace a globe valve. In addition to the savings listed above, there are intangible savings from shorter shutdown time, which is considerable given that the cost of plant shutdown often exceeds the cost of equipment.
For more information on Conval gate and globe valves, contact Piping Specialties, Inc. by calling 800-223-1468 or visit https://www.psi-team.com.

Sunday, December 31, 2017

Happy New Year from PSI

With 2017 coming to a close, all of us at Piping Specialties wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.