Control Valve Actuators
Reed Research Group surveyed Control Engineering subscribers in December 2008 about their use of control valve actuators currently, and going forward. The results presented here are based on 224 completed responses from subscribers who evaluate, specify, recommend, install, and/or purchase these devices. Among these, 46% say they run both batch and continuous processes, 25% run continuous processes only, 14% are batch only plants, and the balance fall into other categories. Liquid handling outnumbers gasses nearly 2:1 with a few percentage points for slurries and powders. Looking ahead to the rest of 2009, prospects for growth are slow, with only 17% of respondents saying their purchases will increase, and 83% looking for the same level as 2008 or a decrease.
Many different size companies responded. A large segment (48%) buy 24 units or fewer annually. A sizable middle group of 34% covers the intermediate space of 25 to 149 units annually, and the large users at 150+ account for 18%. The bulk of valves (75%) have integral actuators, with the balance mounted as a separate item. Pneumatic actuators still dominate at 45%, but electric units are a close second at 40%. Manual designs take most of the balance.
The critical nature of control valve operation comes through when comparing the answers to a number of questions. Reparability and cost factors topped the list of most important factors for selection, followed closely by manufacturer’s reputation and availability from stock. Actuators are expected to perform reliability, but must be economical, and easy to repair or replace when there are problems. Most companies (60%) do their own actuator repairs in house, with the balance split between factory and third-party shops. Generally, actuators operate without a large amount of maintenance, as 46% report that they have to service actuators once every three or more years, and 29% said once per two years. Only 25% require service once per year or less.
|Purchase habits in 2009 seem to reflect current economic conditions. In 2007, 29% of respondents expected purchases to increase, and only 10% anticipated a decrease. Repairs in house have also declined slightly, shifting to third-party providers.|
When it comes to selecting control valves, respondents included comments formed by experience, such as:
“Deal with people that have control valve experience and have the practical knowledge on how the valves need to perform.”
“Research the products completely. Obtain the best match between the product and application and don’t assume that a more expensive unit with more features is going to be the best fit.”
“For industrial environments, you have usually have to pay a little more to get robust equipment, but it is worth it due to MRO savings.”
“Research you application in depth, to ensure the need meets all aspects of the application: serviceability, cleanability, and low replacement costs.”
“Keep it clean and exercise it often.”
“Make support your most important attribute above availability and price.”
Additional results, links, and product information from these vendors are available with this article online at www.controleng.com/archive for February 2009.
|While a few suppliers tend to dominate much of the market, there is still a large variety of manufacturers who have a strong hold on specialty and niche applications.|
|Peter Welander is process industries editor. Reach him at PWelander@cfemedia.com .|