Preventing Cavitation in Industrial Process Control Valves

Example of multi-stage valve trim
designed to eliminate cavitation
Courtesy Flowserve - Kammer

In process control valves, cavitation results from a rapid drop in pressure as liquid passes through the valve. It results in the formation of vapor spaces or bubbles within the valve cavity. When the bubbles move downstream into a larger cross-sectional area, velocity decreases and pressure increases. The higher pressure now surrounding the bubbles causes them to implode, producing shockwaves which propagate through the liquid. These shockwaves can cause metal fatigue and excessive wear on the internals of the valve. The collapsing bubbles also make a discernible sound with accompanying vibration. The cumulative effects of cavitation can cause rapid deterioration of a valve, resulting in reduced control function, frequent need for service, or premature failure.

There are ways to mitigate cavitation. Some involve changes in the process, others, incorporating a properly designed and selected valve with trim that reduces or prevents the conditions that cause cavitation. The paper below, authored by Flowserve, provides an in depth examination of the causes of cavitation, then continues with explanation of how their specialty valves are designed to overcome the conditions that promote it.

There are detailed illustrations showing the specific valve trim features that impede cavitation. Share your process control valve challenges with application experts, combining your process knowledge with their product application expertise to develop effective solutions.

Controlling Cavitation in Industrial Control Valves from CTi Controltech

Self Defense Against Industrial Control System Cyber Threats

Protection from cyber attacks and intrusions should be
a high priority wherever industrial automation is present

Industrial control system owners, operators, and other stakeholders should be aware of their exposure to malicious intrusion and attack by individuals or organizations intent on inflicting physical damage, stealing information, or generally wreaking havoc throughout an industrial operation. The risk of intrusion, regardless of the size or type of facility, is real and deserves the focused attention everyone involved in the design and operation of industrial control systems.

The National Cybersecurity and Communications Integration Center, part of the US Department of Homeland Security, ...

serves as a central location where a diverse set of partners involved in cybersecurity and communications protection coordinate and synchronize their efforts. NCCIC's partners include other government agencies, the private sector, and international entities. Working closely with its partners, NCCIC analyzes cybersecurity and communications information, shares timely and actionable information, and coordinates response, mitigation and recovery efforts. (from www.us-cert.gov/nccic)

The Industrial Control Systems Cyber Emergency Response Team (ICS-CERT) is a division under NCCIC. It has published a set of seven basic steps toward establishing a more secure industrial control system. I have included the publication below, and it is interesting and useful reading for all involved in industrial process control.

Having a fence around an industrial site, with a guarded entry gate, no longer provides the level of security needed for any industrial operation. Read the seven steps. Take other actions to build your knowledge and understanding of the risks and vulnerabilities. Cybersecurity is now another layer of design tenets and procedures that must be added to every control system. It will be a part of your company's best practices and success, now and in the future.

There are uncountable legacy controllers and communications devices throughout industrial America. All need to be reassessed for their vulnerability in the current and upcoming security environment. When reviewing your processes and equipment, do not hesitate to contact CTI-Controltech for assistance in your evaluation of our products.

Seven recommendations for bolstering industrial control system cyber security from CTi Controltech

Vertical Tubeless Boiler - Small Footprint for Hot Water and Steam Production

Vertical Tubeless Boiler
Courtesy Williams & Davis Boilers

Steam and hot water are utilized in quantity throughout many industrial and commercial operations. Boilers, the most common production equipment for steam, are commercially available in a number of configurations, each with its own set of attributes making it an advantageous choice for a particular application.

One type of boiler is the vertical tubeless boiler, so named for the direction of combustion gas flow and its lack of tubes that are utilized in other designs.

Production capacity in a boiler is very dependent upon heat exchange surface area. The orientation of a vertical tubeless boiler results in a design with a significantly smaller footprint than a comparable horizontal boiler. This, obviously, can be very helpful if floor space is scarce in your facility. The rugged, simple design and lack of tubes tends to make these boilers very reliable and simple to maintain. Fueled by oil, gas, or a combination of the two, provides suitability for a wide range of facility installations. The burner is top mounted and the Williams & Davis unit pictured in this article comes fully trimmed and ready to install in most cases. Feedwater treatment and condensate return considerations are generally the same as for any other boiler.

The vertical tubeless boiler can have broad application in commercial and industrial facilities requiring a reliable source of hot water or pressurized steam. Share your hot water or steam requirements with combustion and boiler experts for the most effective solutions.

Two pass vertical tubeless boilers from CTi Controltech

General Purpose Valve for Targeted Applications

Industrial Butterfly Valve
Courtesy Adams Valves, Inc.

This is the Adams Valve WEK series industrial butterfly valve. It is a general purpose valve for many applications involving fresh water, seawater, sewage, hydrocarbon and wet gas.

The WEK valves feature low operating torque, compact design, low weight, and good control characteristics. The sealing system is completely integrated within the body of the valve, utilizing a laminated metal and graphite material. Available sizes range from 3" to 24".

Streamlining promotes smooth movement of the disc through its full travel range, without flutter induced by the flow moving around the disc. Sealing is accomplished when the disc rotates to the closed position and seals tightly against the seat which is incorporated into the body. Tight shut off results from the disc pushing into the seal. Valve operation can be manual, via a handwheel, or automated with a range of electric, hydraulic, or pneumatic actuators.

Share your fluid control, valve, and automation challenges with the engineers at CTI Controltech, combining your process and facility knowledge with their product and application expertise to develop the most effective solutions.

Electro-hydraulic Valve Actuators Applied at Tank Farm

Electro-hydraulic valve actuators
Rotork Skilmatic

Rotork is a global leader in the design and manufacture of valve and damper actuators for industrial applications. The company's Skilmatic line of electro-hydraulic actuators is designed to provide a solution for modulating control and electric failsafe operation in rotary and linear designs. The company has created an animated video illustrating how the actuators can be deployed on control valves in a tank storage application. The presentation provides good detail of the inner workings of the actuator, along with the actuator control unit display. The video is short, but very informative.

Share your valve and automation requirements and challenges with application experts. A combination of your process and facility knowledge and their product application expertise will produce effective solutions.