What Do Control Valves Have to Do with Product Quality?

Manufacturing is a highly competitive business, especially now, with new technologies coming on the scene and new models disrupting the traditional.

With this competition comes enormous pressure to improve efficiency and productivity, while maintaining a level of quality that will keep customers coming back for more. As manufacturers strive to meet these business goals, they often overlook one very crucial element that can help them do so — the control valve.

Put simply: To make a quality product, you need a quality process, which means as little variability as possible. Process variability is determined in large part by a system of control loops, at the heart of which lie control valves. This means that by keeping your control valves working properly, you can reduce process variability and increase product quality.

Let’s look at these concepts a little more closely.

What is quality?

In manufacturing, the most basic definition of quality is “conformance to specifications.” Essentially this means that the product matches the plan.

How do you ensure quality?

Manufacturers do several things to ensure that what comes off the production lines matches the plan.

One approach is to inspect the final product — any product that doesn’t adhere to specifications is disposed of, recycled, or used for something else.

Another approach is to focus further upstream on the process that produced the product. This is the approach advocated by W. Edwards Deming, the distinguished American engineer and consultant who helped Japan rebuild its industry following World War II.

Deming famously said: “Quality control should check the process, not the product.”

In the modern world of quality control, Deming’s statement isn’t without controversy. But most engineers and manufacturers today agree that controlling the process that makes a product is essential to controlling the quality of that product.

Since quality is closely related to consistency, one key to improving it is by reducing process variability.

As Emerson Process Management notes in their Control Valve Handbook:

Any deviation from the established specification means lost profit due to excessive material use, reprocessing costs, or wasted product. Thus, a large financial impact is obtained through improving process control. Reducing process variability through better process control allows optimization of the process and the production of products right the first time.

The control valve’s role in reducing process variability

Manufacturers spend a lot of time and money looking for ways to reduce process variability. Unfortunately, however, these resources are often put in the wrong place. Where they should be looking is at their control valves.

One well-cited study found that as many as 80% of control loops don’t adequately reduce process variability, and that a large part of the problem was the control valves that lie at the center of those loops. Control valve problems have a variety of causes, such as using the wrong valve, under- or oversizing, and deadband.

All these problems mean the valve will fail to adequately regulate process variables like temperature, pressure, and flow. The result is increased process variability, which in turn leads to decreased quality. By solving these problems, manufacturers can reduce process variability, which will in turn improve quality.

Many factors determine product quality — design, raw materials, and so on. But the process that creates that product shouldn’t be overlooked. And the control valve is a major contributor to the success of that process.

View our complete line of Masoneilan control valve products to find the right valve for your application.

This entry was posted in The Valve Expert and tagged , , . Bookmark the permalink.