Monday, August 22, 2016

High Performance Non-Slam Check Valve

high performance dual plate check valve
Crane Duo-Chek dual plate check valve
Check valves are ubiquitous throughout fluid processing operations. These simple devices permit fluid flow in one direction only. While there are numerous design variants available in the marketplace, operation is very similar in all check valves. Fluid pressure and movement in the desired direction moves a plate, plug, ball, or other obstruction to a position that allows flow to pass. The plate or other obstruction has a design countervailing force applied to it by a spring, gravity, or some other means that will move the trim to the closed position. When pressure drop across the valve decreases below the design level, the trim will close. Fluid pressure exerted on the outlet side of the valve will maintain a closed position in the valve. In this manner, a check valve allows fluid to pass in one direction, but not in the reverse.

Beneficial features of a check valve would include some or all of the following:

  • Lightweight and compact design
  • Tight shutoff that meets any applicable standards
  • Low pressure drop when open
  • Operation that minimizes seal wear
  • Installation simplicity and flexibility
  • Easy to insulate
  • Low maintenance requirements
  • No slamming to the closed position
  • No valve chatter
  • Available in numerous configurations to meet wide range of applications
Share your fluid process control challenges with a product application specialist. Combine your process knowledge with their product application expertise for effective solutions.

Tuesday, August 16, 2016

New Piping and Pipeline Specialties Catalog

heavy duty industrial piping and pumps
Titan Flow Controls products are utilized throughout piping systems
Mountain States Engineering and Controls handles the full line of Titan Flow Control products and has the application expertise and product knowledge to help customers select the right products, properly configured for the job at hand.

The company recently published a new and updated catalog containing all of their standard products. Titan Flow Controls manufactures a broad range of flow control products.

  • Y Strainers
  • Duplex Strainers
  • Basket Strainers
  • Check Valves
  • Butterfly Valves
  • Pump Protection
  • Specialty Products
  • Custom Assemblies and Fabrications
The latest edition of the Titan FCI catalog is included below. All the technical assistance needed for properly selecting and configuring the right product for your application is available from the experts at Mountain States Engineering and Controls.

Tuesday, August 9, 2016

Methods of Measurement For Boiler Drum Water Level

gas fired boilers in boiler room
There are numerous boiler water level measurement methods
Steam boilers have a long history in commercial, industrial, even residential applications. The steam they produce can be used to deliver heat, or to drive mechanical equipment and other processes. Maintaining the right boiler operating conditions is essential to safe operation and achieving the best use of fuel.

Boiler water level measurement is one of the essential elements of proper operation. Accurate and effective level measurement will indicate water levels that are too high or too low, both of which can have negative impact.

Spirax Sarco, a globally recognized leader in the development and production of steam related specialties, has developed content that summarizes various methods and technologies used to measure water level in boilers. Each is described in detail, with explanations of the technology, including some mathematical formulas. The piece is well illustrated and some advantages associated with each method are included. The document is from the company's website, under the Resources > Steam Engineering Tutorials section and provided in its entirety below.

Share your steam related challenges with a Spirax Sarco representative, specialists in helping achieve maximum performance from steam systems.

Tuesday, August 2, 2016

Corrosion Resistant Cooling Towers Allow Aggressive Water Treatment

cooling tower corrosion resistant plastic construction
Corrosion resistant cooling tower
Courtesy Delta Cooling Towers
Unless you are located in the northern or southern polar regions, churning away on the roof of the building in which you may work, or mounted on a pad adjacent to it, is likely an important unit of equipment. It is essential to climate control in the building, and possibly an integral heat rejection component for an industrial process. Yes, I am talking about cooling towers. While hardly glamorous, without their successful operation, much of your operation will grind to a halt. 

There is substantial cost involved in the operation of a cooling tower, including energy, water, treatment chemicals, and more. Corrosion and the accumulation of fouling material can measurably reduce overall cooling efficiency. Even modest accumulation can slash energy efficiency by 5%, increasing operating costs in a marked way.

Keeping a cooling tower operating near its design capacity requires a commitment to a regular maintenance and inspection schedule. When deficiencies are found, they should be corrected within a reasonably short time frame. Water treatment, to improve performance or reduce maintenance burden, can sometimes be overly aggressive and impart some negative side effects to the equipment. Plastic cooling towers provide a high level of resistance to even the most aggressive water treatment chemicals. Cooling towers fabricated from plastics can carry warranties extending to 20 years.

Water cooling towers are an important operational component of your infrastructure, as well as a significant continuing cost center. They should be cared for as an important appliance. Avoid choosing a "Run to failure" maintenance program.

There is much to consider when adding or replacing a cooling tower. Share your project requirements and challenges with an application specialist. Combining your process and operational expertise with their product application knowledge will produce an effective solution.

Back Pressure Regulator or Pressure Regulator Valve, Appropriate Application

pressure regulator valve
Pressure Regulator Valve
Courtesy Pentair Cash Valve
Fluids move throughout processes, driven by pressure produced with mechanical or naturally occurring means. In many cases the pressure generated by the driving source is substantially greater than what may be desired at particular process steps. In other cases, the operation may dictate that a minimum pressure be maintained within a portion of the process train. Both cases are handled by the appropriate valve type, designed specifically to regulate pressure.

A pressure regulating valve is a normally open valve that employs mechanical means, positioning itself to maintain the outlet pressure set on the valve. Generally, this type of valve has a spring that provides a countervailing force to the inlet pressure on the valve mechanism. An adjustment bolt regulates the force produced by the spring upon the mechanism, creating an equilibrium point that provides flow through the valve needed to produce the set outlet pressure. A typical application for a pressure regulator is to reduce upstream or inlet pressure to a level appropriate for downstream processing equipment.

Back pressure valves are normally closed, operating in a logically reversed fashion to pressure regulators. Where pressure regulators control outlet pressure, a back pressure valve is intended to maintain inlet pressure.  Similar internals are present in the back pressure valve, with the valve action reversed when compared to a pressure regulator. An inlet pressure reduction in the back pressure valve will cause the valve to begin closing, restricting flow and increasing the inlet pressure. A representative application for a back pressure valve is a multi-port spray station. The back pressure valve will work to maintain a constant setpoint pressure to all the spray nozzles, regardless of how many may be open at a particular time.

Both of these valve types are available in an extensive array of sizes, capacities, pressure ranges, and materials of construction to accommodate every process requirement. Share your fluid control challenges with a process control specialist. Combining your process knowledge with their product application expertise will produce effective solutions.

Tuesday, July 19, 2016

Operating Principle - Solenoid Valve

Solenoid magnetic field
A solenoid is an electric output device that converts electrical energy input to a linear mechanical force.

At the basic level, a solenoid is an electromagnetic coil and a metallic rod or arm. Electrical current flow though the coil produces a magnetic field, the force of which will move the rod. The movable component is usually a part of the operating mechanism of another device. This allows an electrical switch (controller) to regulate mechanical movement in the other device and cause a change in its operation. A common solenoid application is the operation of valves.

solenoid valve basic parts
Solenoid valve basic parts
A plunger solenoid contains a movable ferrous rod, sometimes called a core, enclosed in a tube sealed to the valve body and extending through the center of the electromagnetic coil. When the solenoid is energized, the core will move to its equilibrium position in the magnetic field. The core is also a functional part of valve operation, with its repositioning causing a designed changed in the valve operating status (open or close). There are countless variants of solenoid operated valves exhibiting particular operating attributes designed for specific types of applications. In essence, though, they all rely on the electromechanical operating principle outlined here.
A solenoid valve is a combination of two functional units.

  • The solenoid (electromagnet) described above.
  • The valve body containing one or more openings, called ports, for inlet and outlet, and the valve interior operating components.

Flow through an orifice is controlled by the movement of the rod or core. The core is enclosed in a tube sealed to the valve body, providing a leak tight assembly. A controller energizing or de-energizing the coil will cause the valve to change operating state between open and closed, regulating fluid flow.

Share your control valve requirements and challenges with an application specialist. Combining your process application knowledge with their product expertise will produce the most effective solutions.

Wednesday, July 13, 2016

Eight Process Control Valve Selection and Application Criteria

Sliding Gate Control valve with actuator
Sliding Gate Control Valve
Schubert & Salzer
Fluid processes will employ control valves to regulate flow or pressure in between the extremes of fully open and fully closed. Their function and design is specifically different from shutoff valves, which are designed and intended for isolation of segments of a fluid system. Improperly applying or sizing a control valve can have consequences in operation, productivity, and safety ranging from nuisance level to critical. Here are some items that should always be part of your selection  and application consideration.

  • A control valve is not intended to be a an isolation valve and should not be used for isolating a process segment. Make sure you select the appropriate valve for the function to be performed.
  • Select materials of construction that will accommodate the media and the process conditions. Take into consideration the parts of the valve that come in contact with process media, such as the valve body, the seat and any other wetted parts. Operating pressure and temperature impact the materials selection for the control valve, too. Conditions surrounding the valve, the ambient atmosphere and specific local conditions that may expose the valve to corrosives should be included in your thinking.
  • Install flow sensors upstream of the control valve. Locating the flow sensor downstream of the control valve exposes it to an unstable flow stream which is caused by turbulent flow in the valve cavity.
  • Establish the degree of control you need for the process and make sure your valve is mechanically capable to perform at that level. Too much dead-band leads to hunting and poor control. Dead-band is roughly defined as the amount of control signal required to affect a change in valve position. It is caused by worn, or loosely fitted mechanical linkages, or as a function of the controller setting. It can also be effected by the tolerances from mechanical sensors, friction inherent in the the valve stems and seats, or from an undersized actuator.
  • Consider stiction. Wikipedia defines it as "the static friction that needs to be overcome to enable relative motion of stationary objects in contact". This can be particularly evident in valves that see limited or no position change. It typically is caused by the valves packing glands, seats or the pressure exerted against the disk or other trim parts. To overcome stiction, additional force needs to be applied by the actuator, which can lead to overshoot and poor control.
  • Tune your loop controller properly. A poorly tuned controller causes overshoot, undershoot and hunting. Make sure your proportional, integral, and derivative values are set.  This is quite easy today using controllers with advanced, precise auto-tuning features.
  • Avoid oversizing control valves. They are frequently sized larger than needed for the flow loop they control. If the control valve is too large, a small percentage of travel or position change could produce an unduly large change in flow, which in turn can make stable control difficult. Unstable control can result in excessive movement and wear on the valve. Try to size a control valve at about 70%-90% of travel.
  • Think about the type of control valve you are using and its inherent flow characteristic. Different types of valves, and their disks, have very different flow characteristics. The flow characteristic can be generally thought of as the change in rate of flow in relationship to a change in valve position. Globe control valves have linear characteristics which are preferred, while butterfly and gate valves tend to have non-linear flow characteristics, which can cause control problems.  In order to create a linear flow characteristic through a non-linear control valve, manufacturers add specially designed disks or flow orifices which create a desired flow profile.
These are just a few of the more significant criteria to consider when selecting and applying a process control valve. Consider it good practice to discuss your selection and application with a product application expert to confirm your final selection. Combing your process knowledge with their application expertise will provide the best outcome.