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 evaluateCONTROL ENGINEERING China版权所有, specifywww.cechina.cn, 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 ou

tnumbers 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控制工程网版权所有, 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控制工程网版权所有, as 46% report that they have to service actuators once every three or more yearsCONTROL ENGINEERING China版权所有, and 29% said once per two years. Only 25% require service once per year or less.

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