Piping Specialties and PSI Controls Blog

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.

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Understanding How Control Valves Work

Understanding 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.

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

Superior Rugged Construction - Conval 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.
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.
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.

Link-Seal Modular Seals, Century-Line Sleeves, Cell-Cast Disks Engineering Manual & Buyers Guide

Link-Seal Modular Seals, Century-Line Sleeves, Cell-Cast Disks Engineering Manual & Buyers Guide from Piping Specialties, Inc and PSI Controls

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.

Drexelbrook Total Tank Level System

Ametek is a world leader in level measurement technology products. The Ametek Drexelbrook Total Tank Level System is a state-of-the-art measurement instrument utilizing magnetostrictive technology to accurately determine total product level, interface level, and temperature in liquid tanks. Offered in either a stainless steel rigid, and flexible Kynar version, these probes are capable of working in tanks from as low as 2 feet up to 50 feet high.

Magnetostriction is one of many level technology options available to industrial users today. For liquid measurements, especially when a water interface exists, it unquestionably offers the most versatile and accurate solution on the market. Ametek now has an excellent solution to manage multiple variable measurements in storage tanks. Ametek Drexel Brook now offers the Total Tank Level Multi-variable Transmitter to measure both level and temperature with Modbus, 4 to 20 milliamp, and HART output capability.

The ability to measure and track various tank conditions in realtime is critical in today's process environments. The multi-variable capability of the Drexelbrook Total Tank Level System provides simultaneous data for total level, interface level, product temperature, water interface temperature total average temperature, and volume for all liquid components in the tank. Standard industrial level instruments utilizing guided wave capacitive or radar technologies provide 3 to 5 millimeter accuracy. Higher cost tank gauging technologies will provide 1 to 2 millimeter accuracy. Only magnetostrictive technology can provide superior sub 1 millimeter accuracy levels consistently under most process conditions. In addition, the Drexel Brook Total Tank Level System is fully compensated across the entire operating range of process temperatures, up to 257 degrees Fahrenheit.

One of the most challenging applications is the measurement of an interface level between two significantly different density liquids. The most common of these is oil and water. There are only a few technologies that claim to be able to make this measurement. Guided wave radar and magnetostriction are two of the most common. Guided wave radar technology is based on microwave pulses that are transmitted down a probe and are partly reflected by the product surface, as well as the interface level surface. In applications where both liquids have stabilized, guided wave radar technology can accurately determine both the product and interface level. If an emulsion layer forms between the two liquids this can significantly diminish the measured value, or even cause the complete loss of the signal. If this occurs, it is extremely difficult to maintain control of the process. Using a float based magnetostrictive technology, the measurement becomes straightforward. Both product and interface return signals are generated by the reflection of a magnetically induced strain on the measurement wire, which is embedded in the probe. Magnets are positioned on the probe based on their specific gravity matched to the liquids being measured. This ensures that the float will always maintain its position, both on the top liquid level, and at the interface position. The lower measurement signal remains unaffected by the formation of an emulsion. Comparing the two technologies clearly shows the advantage of magnetostrictive technology whenever emulsion layers are present. Guided wave radar can only be used to measure the overall level reliably under all conditions, while the Drexelbrook Total Tank Level System guarantees the continuous and accurate measurement of the overall level, and the interface, even under emulsion conditions.

The Drexelbrook Total Tank Level System easily integrates into existing control systems that have standard protocols, such as Modbus, 4 to 20 milliamp loop, or HART communications. Each instrument can beset up directly through the Ametek STExplorer software which can be downloaded free of charge. This makes installation and commissioning of the instrument easy. Drexelbrook's reliable magnetostrictive level probes have been installed in more than 100,000 systems worldwide. They are proven over years of grueling weather conditions and trusted by some of the largest companies in the world.

Please watch the video below for more information. To discuss a tank level application, contact Piping Specialties by visiting https://www.psi-team.com or call 800-223-1468.

Basics of Process Temperature Sensors: RTDs and Thermocouples

Industrial thermocouples (Marsh Bellofram TCP)

Proper temperature sensor selection is key to getting useful and accurate data for maintaining control of a process. There are two main types of temperature sensors employed for industrial applications, thermocouple and resistance temperature detector (RTD). Each has its own set of features that might make it an advantageous choice for a particular application.

Thermocouples consist of a junction formed with dissimilar metal conductors. The contact point of the conductors generates a small voltage that is related to the temperature of the junction. There are a number of metals used for the conductors, with different combinations used to produce an array of temperature ranges and accuracy. A defining characteristic of thermocouples is the need to use extension wire of the same type as the junction wires, in order to assure proper function and accuracy.

Here are some generalized thermocouple characteristics.

Various conductor combinations can provide a wide range of operable temperatures (-200°C to +2300°C).
Sensor accuracy can deteriorate over time.
Sensors are comparatively less expensive than RTD.
Stability of sensor output is not as good as RTD.
Sensor response is fast due to low mass.
Assemblies are generally rugged and not prone to damage from vibration and moderate mechanical shock.
Sensor tip is the measuring point.
Reference junction is required for correct measurement.
No external power is required.
Matching extension wire is needed.
Sensor design allows for small diameter assemblies.

Industrial RTDs
(Marsh Bellofram TCP)

RTD sensors are comprised of very fine wire from a range of specialty types, coiled within a protective probe. Temperature measurement is accomplished by measuring the resistance in the coil. The resistance will correspond to a known temperature.

Some generalized RTD attributes:

Sensor provides good measurement accuracy, superior to thermocouple.
Operating temperature range (-200° to +850°C) is less than that of thermocouple.
Sensor exhibits long term stability.
Response to process change can be slow.
Excitation current source is required for operation.
Copper extension wire can be used to connect sensor to instruments.
Sensors can exhibit a degree of self-heating error.
Resistance coil makes assemblies less rugged than thermocouples.
Cost is comparatively higher.

Each industrial process control application will present its own set of challenges regarding vibration, temperature range, required response time, accuracy, and more. Share your process temperature measurement requirements and challenges with a process control instrumentation specialist, combining your process knowledge with their product application expertise to develop the most effective solution.