Tuesday, July 14, 2015

Reduce Process Downtime With Device Protection

The list of possible events or conditions that can crash your process is immense. Fortunately, most of the possible occurrences are tagged with extremely low probabilities that allow us to sleep at night without worrying about impending disaster. However, we are engineers and industrial process operators. We are supposed to make sure everything keeps flowing smoothly. Here is a small part of your world that can be made more secure with some practical consideration.

Oil and Gas Industry Installation
Oil and Gas Industry Installation
Industrial processes require two very basic elements, measurement and control. The instruments used to measure process variables and the control devices employed to change them must be kept in operation, in many cases, all the time. You invest time to research available products, searching for the right materials of construction, signal output, accuracy, and a whole range of other attributes that will make your selection perfectly suited to the process requirements. This technical selection process is an essential part of the process design and implementation. What other aspects of your measurement and control hardware may play an important part in maintaining process uptime?

Give some consideration to the conditions or events that might take a particular instrument or control device out of action. With the application of imagination and good judgement, combined with some help from an experienced application engineer, you can develop additional items to incorporate into the design and installation of your process measurement and control elements. Here are some basics to get you started.

What is the security exposure for your device?

Not considered so much in the past, thinking about how someone without the best interests of your organization in mind might create havoc should be part of your general assessment of each installation. Fully understanding the access pathways, physical or otherwise, to your instruments and controls is necessary to thwart unauthorized tinkering or malicious mischief.

What are the real extremes of weather conditions occurring at the device’s physical location?

Data on the weather for every industrialized country, and some that are not so industrialized, is freely available. Check it out. Forget about the average range of conditions. Look for conditions that occur once in a hundred years or more. A small hardening of your installation might provide the needed capacity or strength to withstand the worst weather in a hundred years. Challenge your device vendors with these weather conditions. It might leave your process the only one standing after that freak storm.

What extreme conditions may be generated by the process that could lead to device damage or deterioration?

The normal process conditions are generally known. Consider, though, the instantaneous or short duration occurrences that, while associated with normal operation, may have an adverse impact on installed measurement and control devices. What happens when elements start or stop, open or close? Are there malfunctions of one device that could snowball into a string of failures of other devices?

process measurement instruments
Process Measurement Instruments
What are the physical contact hazards where the device is installed?

Measurement and control equipment needs to be provided with personnel access for maintenance, repair, even real-time observation in some cases. Along with human access comes the wide array of misbehaviors of which we are all capable. There is not one of us that has not tripped and fallen, dropped something, or bumped into something with undesirable results. Plan for contact with people and the things they may carry around your plant or installation. Locate sensitive gear away from major traffic areas and provide protection from unplanned contact with people, dollies, carts, tools, boxes and anything else that may pass through the area.

Are your devices and equipment protected from moisture?

Electronics are an integral part of modern industrial measurement and control equipment. Electronic devices will be damaged or destroyed by exposure to excessive levels of moisture. Moisture exists everywhere in our environment, primarily as vapor or liquid. The ability of moisture to find its way into unprotected enclosures is well known, and you should take precautions to prevent its entry and accumulation in your devices.
Protecting your installed process measurement and control equipment is an investment that pays dividends in process uptime and reduced repair effort and cost. It is challenging to think of all possible hazards, so consult an experienced engineering sales team and tap into their field experience to make your project as good as it can be.

Friday, June 26, 2015

Selecting The Right Valve Type - Ball Valves

Applications that can be characterized as industrial fluid handling or process control are vast in number and variety, each being highly specialized and customized to specific circumstances. It’s no surprise that, given the array of potential application conditions, there are countless different valve arrangements, types, and technologies to choose from.
Industrial Ball Valve
Large Industrial Ball Valve
Courtesy HS Valve Co.
Ball valves, like many valve types, are named for their closure mechanism. A spherical shaped element is placed in the fluid flow path, with the ability to rotate its position around an axis. The axis is a shaft or other device that connects to an actuator on the exterior of the valve and flow path. The actuator can be a simple handle or an element of a valve automation system. The “ball” in the ball valve has an opening through its center, usually round to mimic the shape of the connected pipe. As the ball is rotated, the opening aligns with the inlet an outlet of the valve body, allowing fluid to pass. A counter-rotation that aligns the opening with the sides of the valve body, away from the flow path, stops the fluid flow. So, compared with other valve technologies, when would a ball valve be a preferred application choice? Here are some points to consider.

Application advantages of ball valves:

  • Leak-proof service
  • Well suited for processes requiring only full flow or no flow operation.
  • Rapid open and close action, requiring only 90 degrees of rotation from fully open to fully closed.
  • Comparatively light weight and small size.
  • Wide range of construction material options for body, ball, and seals make them suitable for many applications.
  • Require only moderate force to control valve position.
  • Flow path opening in the ball will often be “full port”, providing same cross section as the connected pipe and adding very little restriction or pressure drop to the flow.
  • Low maintenance, with no lubrication required.

What considerations might be cause to consider a different valve type?

  • There can be some residual fluid trapped in the valve when it closes.The trapped fluid will be released when the valve is opened. Consider what impact, if any, this may have on your process.
  • Balls valves are generally not suited for throttling applications. When partially open, the seals that surround the ball are exposed to the flow velocity and can deteriorate quickly.
  • Valve seals are usually elastomeric materials. Verify seal materials are compatible with the fluid type, character and operating temperature.

These comments are general in nature and there are some specialized ball valve designs that have overcome some of the general disadvantages noted here. Have a conversation with a valve specialist about your application and benefit from their experience and knowledge.

Monday, June 22, 2015

Selecting the Right Valve Type - Gate Valves

There are many types of valves available for industrial fluid handling and process control applications. Specifying the proper valve type for an application can be made easier with some basic knowledge about the application strengths and weaknesses of the various valve types.

gate valve cutaway view
Gate Valve Cutaway View
Courtesy DHV Industries
Gate valves open and close by changing the position of a rectangular or round wedge (the gate) in the fluid flow path. The sealing surfaces are arranged in a planar fashion and the gate, which is commonly either flat or wedge shaped, slides along the sealing surface from the open to closed position. Because of the cross-sectional shape of pipes, which is often mimicked in the valve body, the size of the opening created as the gate valve opens and closes does not change at the same rate as the percentage of total available movement of the gate. This non-linear aspect of valve operation can make a gate valve less suitable for an application where flow rate must be accurately controlled across the range from fully open to fully closed. Complicating throttling operations further is the possibility of the gate vibrating when partially open, due to the fluid flow around the gate assembly. Unless specifically designed for throttling, gate valves are generally best suited for applications requiring either full flow or no flow. Because of its operating nature and construction, a gate valve may prove to be the appropriate selection, based upon the type of media or fluid which is being controlled.

In addition to specifying the manner in which the valve will be connected within the piping system, consideration should be given to construction of the valve body. If it may be necessary to inspect, service, or clean the valve interior, look for a bonnet connection that will permit suitable access to the valve interior.

Once you have decided that a gate valve will be the most suitable type for your application, there are many other considerations in valve selection. Draw on the experience and knowledge of coworkers, maintenance technicians, and valve sales engineers to help specify a valve assembly that meets the needs of all project stakeholders.

Friday, June 19, 2015

Industrial Control Valve Basics - An Introduction

Industrial process control valve
Globe Valve with Pneumatic Actuator
Courtesy Warren Controls
Valves, mechanical devices able to control flow or pressure in a process or system, are as ubiquitous as any industrial process control element. As essential components of piping systems conveying liquid, gas, vapor, or slurry, valves are a component with which almost every industrial process and control engineer will require more than entry level familiarity. They are the controlling element in almost any fluid handling system. What are some of the very basic knowledge points for specifying and selecting a control valve?

There are numerous types of valves available, including butterfly, ball, check, globe, gate, diaphragm, plug, and control valves as the most common. Particular valve types can be better suited to the medium being controlled, or have functional capabilities making them a better selection for your process application. Within each type there will be a wide range of options and features that allow for close tailoring of the complete valve assembly to match the application requirements.  Some valves can be self-operated, while others require manual operation. A pneumatic, hydraulic, or electric actuator can be employed on certain configurations to provide for remote control of the valve by a human operator or automatic controller.
General valve functions include:
  • Flow start or stop
  • Flow rate increase or reduction
  • Diversion of flow in another direction
  • Regulation of a flow or process pressure

Industrial process control valves are often classified according to their mechanical movement. Some common examples include:
  • Linear motion valves, in which the closure element moves in a straight (linear) direction to control the flow. Gate, globe, and diaphragm valves are in this category.
  • Rotary motion valves have a closure that follows an angular or circular path. Butterfly and ball valves are in this group.
  • Quarter turn valves, a subset of the rotary motion class, traverse from the open to closed state when the closure element (for example, the ball in a ball valve) is rotated through a quarter of a full turn. This type is best suited for operations calling for either fully open or closed regulation, with no need for control at points in between those two states.

Each industrial control valve application and installation will have its own set of very specific requirements. The goal of the specification and selection process should be to provide safe operation, low maintenance requirements, robust and accurate operation. A manufacturer's sales engineer can be a useful source for application and specification information and assistance.
Oil Pipeline Valve
Ball Valve Installed in Pipeline
Courtesy DHV

Thursday, June 11, 2015

The Often Undervalued Sales Engineer

Call a sales engineer
Sales engineers add value.

Process and control equipment is most often sold with the support of sales engineers working for the local distributor or representative. Realizing what they have to contribute, and taking advantage of this available talent, will help you save time, cost, and also assist in achieving a better outcome for the project.

Consider these contributions:

Product Knowledge: Sales engineers, by the nature of their job, are current on new products, their capabilities and their proper application. Unlike information available on the Web, sales engineers get advanced notice of product obsolescence and replacement. Also, because they call and work with so many different types of companies, sales engineers are a wealth of tacit knowledge that they readily share  with their customers.

Experience: As a project engineer, you may be treading on fresh ground regarding some aspects of your current assignment. You may not have a full grasp on how to handle part of a control loop. Call in the local sales person - there can be real benefit in connecting to a source with past exposure to your current issue.

Access: Through a technical sales engineer, you may be able to look “behind the scenes” with a particular manufacturer and garner important information not publicly available. Sales reps deal with people, and make it his/her business to know what’s going on with products, companies, and industries.

Of course, sales engineers will be biased. Any solutions proposed are likely to be based upon the products sold by the representative. But the best sales people will share the virtues of their products openly and honestly, and even admit when they don’t have the right product. This is where the discussion, consideration and evaluation of several solutions become part of achieving the best project outcome.

As an engineer who designs or manufactures a product or process, it's highly recommended you develop a professional, mutually beneficial relationship with a technical sales expert. Look at a relationship with local sales engineer as symbiotic. Their success, and your success, go hand-in-hand.

Friday, May 29, 2015

Industrial Valve Body Style and Flow Path: A Visual Illustration

fluid dynamics image
(Image courtesy of Wikipedia)
There are many types of valves body styles, each with their own unique flow characteristic and pattern. Valve design generally dictates optimum application service for any given use. For instance, globe or diaphragm valves provide excellent flow control because of a very linear flow characteristic and are used widely as flow control valves. Conversely, standard ball or butterfly valves are not good control valves because of their very non-linear flow characteristic, and special modifications need to be made to their discs or balls to improve linearity.

The following video illustrates the design and flow pattern for (4) types of valve:

Monday, May 18, 2015

And Now for A Little Shameless Self Promotion ...

A little shameless self promotion to spread the word of what lines Mountain States Engineering and Controls carries should anyone out there need assistance.

MSEC, Inc. is a Manufacturer's Representative & Distributor of process equipment and controls headquartered in Lakewood, Colorado since 1978.

We serve the markets of Colorado, New Mexico, Wyoming, Montana, Utah, Nevada, Idaho, and the western Dakotas.