Friday, May 24, 2019

Globe Control Valves

Globe Control Valves
Internal view of globe control valve (Masoneilan)
Globe control valves work differently when compared to gate valves, ball valves, butterfly valves and plug valves in process control applications. They are primarily used to control the flow inside pipes, and are popular in a wide variety of industries. Globe control valves are ideal in situations where precise control is required. They are used to regulate flow in pipelines with a high degree of accuracy by regulating a pressures drop created in the valve body that allows the fluid to pass through the passageway (port) in the valve body. The control valve stem provides linear motion to bi-directionally control flow, opening and closing the valve by changing the distance between valve disc and seat. The flow in the pipeline changes according to the position of the disc lifting from the seat. The movement is controlled through the use of manual operators, or through the use of electric or pneumatic actuators.

Applications of Globe Control Valves 

Globe control valves are used in many different industries, but particularly in the petrochemical and power generation industries on fuel oil pipes, chemical feed systems, steam pipes, as well as cooling water and feedwater systems.  Other industrial applications of globe valve include boiler, main steam vents, and turbine lube oil systems.

Pros

Globe control valves have many advantages that make them preferable over other valve designs. Globe control valves have excellent shut-off and throttling capabilities. In addition, globe valves are easy to maintain and repair compared to other valves.

Cons

Globe control valves have also certain shortcomings. For instance, globe valves have an S-shaped flow pattern (as opposed to a straight-through flow pattern) which creates a significant pressure drop making them unsuitable for applications constant pressure is required.  Another shortcoming of the globe valves is they generally require greater torque to open and close, requiring larger actuators to properly seat the valve.

For more information on industrial globe valves, or any type of industrial valve, contact Classic Controls by calling 863-644-3642 or by visiting https://classiccontrols.com.

Friday, April 19, 2019

Reduce Standby Cycling to Optimize Boiler Operation

gas fired boilers in a boiler room
There are savings to be had by controlling boiler standby cycling
Heating of commercial and institutional buildings presents a case where there are energy savings available through the application of an additional controller able to substantially reduce boiler operation time.

Building owners, boiler engineers, operators and other stakeholders will benefit from this simple and understandable video explanation of some of the inefficiencies associated with boiler operation, and how incorporating a better control method can minimize boiler dry firing (also called standby cycling). Boiler operation costs can be reduced between 10% and 25%, with a commensurate reduction in carbon footprint, by including the Fireye NXM2G control in the boiler control system.

Watch the video. It's just a few minutes and explains the source of the inefficiency, as well as the solution, in a manner understandable to everyone. More information is available from a combustion product specialist, who can help evaluate the efficiency of your current system or assist with incorporating the latest energy saving features and design into a new installation.

Monday, March 25, 2019

Clamp-on Ultrasonic Flow Measurement of Natural and Process Gases


FLEXIM‘s ultrasonic gas flow meters use the proven clamp-on transit-time correlation technique also employed for the F series liquid meters. Special ultrasonic transducers are simply clamped onto the outside of the pipe and never come in contact with the gas.

FLUXUS® G represents the ideal solution for non-invasive gas flow measurement. FLEXIM’s non-invasive technology is an advantageous and cost-effective alternative to conventional methods, particularly with chemically aggressive, poisonous or high pressure media. With their extremely wide turn-down ratios, the instruments of the FLUXUS® G series register even the smallest flows.

Non-invasive Measurement

  • No contact with the medium, therefore no possibility of chemical attack. No need for expensive special materials (sour gas applications for example)
  • No wear and tear, even with high flow velocities or with gas containing particles
  • No clogging of small bore impulse lines with deposits, condensate, inhibitors, oil vapors, dust (as happens when using impulse lines in the measuring system)
  • Insensitive to dust and humidity

Classic Controls, Inc.
https://classiccontrols.com
863-644-3642

Tuesday, March 12, 2019

Plant-wide Condition Monitoring

In addition to the most important assets found in industrial facilities, there are often a host of “supporting” assets that make up the balance of the plant such as pumps, motors, blowers, heat exchangers, fans, and others. This auxiliary or plant-wide equipment may be spared or sacrificed, and its impact on the process stream may vary from moderate to minor. Regardless, such machines—just like their more highly important counterparts—can benefit from Condition Monitoring. Condition Monitoring provides affordable, effective portable and permanent condition monitoring solutions that are delivering tangible benefits for tens of thousands of customers around the globe.

Financial Justification

For many assets, failure can mean substantial or total loss of production, often worth millions per day. Or it can lead to the release of hazardous substances, fires, and even explosions— resulting in a severe safety hazard as well as fines for violating environmental regulations.

Maintenance Costs

When viewed on a per-asset basis, maintenance costs for plant-wide assets can appear modest. However, when viewed collectively across the dozens, hundreds, or even thousands of assets in a typical plant, these costs can be appreciable. Reducing the maintenance costs on each asset through effective condition monitoring—even by a mere 10%—has a large impact on plant profitability. Condition Monitoring is a planning tool that allows more effective insight in planning and asset management, allowing maintenance to be done in advance of a functional failure.

Things to think about as you move towards Predictive Maintenance:
  • 90% of failures are NOT time-based.
  • 50% of companies site maintenance and reliability as a top priority.
  • It costs 6x as much for unplanned events vs. planned maintenance in process industries.
  • A 60% estimated increase in environmental, health and safety spending among global exploration & production companies.
  • 50% of workforce to retire in the next 5 to 10 years. Knowledge & experience is not being transferred.
Potential impact of a conditioning monitoring program and the move towards Predictive Maintenance:
  • -70% Machinery breakdowns 
  • -40% Plant downtime
  • -50% Maintenance costs
  • +25% Production
For more information on Plant-wide Condition Monitoring, contact Classic Controls by calling 863-644-3642 or visit their web site at https://classiccontrols.com.

Thursday, February 28, 2019

The Yokogawa YS1700 Replaces Obsolete Siemens/Moore 353

Yokogawa YS1700
Now that entire Moore/Siemens 350 family is obsolete, are you considering upgrading to a DCS?
Are you concerned about the cost and time for a new installation, application development and personnel training?

Is it possible that the new equipment vendor may again leave you stranded with their equipment as their core business is not industrial automation and control?

We have a better solution for you: Yokogawa and its YS1700 PID loop controller. Yokogawa has been providing industrial solutions, as their primary business, for over a century and their YS1700 will keep you off of eBay looking for spare 353 parts.

Monday, February 25, 2019

Pneumatic Actuator Types

Pneumatic valve actuators all provide the same function:  They convert air pressure to rotational movement and are designed to open, close, or position a quarter-turn valve.  These include ball valves, plug valves, butterfly valves, or other types of 90 degree rotational valves.

The basic design variations of pneumatic valve actuators are as follows:

  • Scotch-yoke
  • Rack and pinion
  • Rotary vane

Let's review each of these in detail:

Scotch-yoke Actuators

Scotch-yoke ActuatorThese actuators come in a multitude of sizes, but are usually used on larger valves because they can produce a very high torque output.  They employ a pneumatic piston mechanism to transfer movement to a linear push rod.  That rod, in turn, engages a pivoting lever arm to provide rotation. Spring return units have a large return spring module mounted on the opposite end of the piston mechanism working directly against the pressurized cylinder.




Rack & Pinion Actuators

Rack & Pinion Actuator
These actuators are sometimes referred to as, “lunch box,” because they, well, look like a lunch box. This actuator uses opposing pistons with integral gears to engage a pinion gear shaft to produce rotation. They are usually more compressed than a scotch yoke, have standardized mounting patterns, and produce output torques suitable for small-to-medium sized valves.  Rack and pinion nearly always include standard bolting and coupling patterns to directly attach a valve, solenoid, limit switch or positioner.  One of their features include several smaller coil springs mounted internally, which provide the torque to return the valve to its starting position.


Rotary Vane Actuators

Rotary Vane Actuator
These actuators are usually used when the application requires a significant space savings.  They take up less space when comparing size-to-torque with rack and pinion and scotch yoke. Rotary van actuators also benefit from a reputation of longevity.  They contain fewer moving parts than other types of pneumatic valve actuators.  Rotary vane actuators use externally mounted, helically wound "clock springs" for their spring return mechanism.

When considering the choice of pneumatic valve actuators, your decision comes down to size, power, torque curve and the ease of adding peripherals. To ensure that your valve actuation package will be optimized for safety, longevity, and performance, the advice of a qualified valve automation expert should be sought out. That expert will be able to help you with the best selection of the appropriate valve actuator for any quarter turn valve application.