Description
One way to reduce the actuator air chamber volume is to use a piston actuator rather than a spring-anddiaphragm actuator, but this is not a panacea. Piston actuators usually have higher thrust capability than spring-anddiaphragm actuators, but they also have higher friction, which can contribute to problems with valve response time.
To obtain the required thrust with a piston actuator, it is usually necessary to use a higher air pressure than with a diaphragm actuator, because the piston typically has a smaller area. This means that a larger volume of air needs to be supplied with its attendant ill effects on the dynamic time. In addition, piston actuators, with their greater number of guide surfaces, tend to have higher friction due to inherent difficulties in alignment, as well as friction from the O-ring. These friction problems also tend to increase over time.
Regardless of how good the O-rings are initially, these elastomeric materials will degrade with time due to wear and other environmental conditions. Likewise, wear on the guide surfaces will increase the friction, and depletion of the lubrication will occur. These friction problems result in a greater piston actuator deadband, which will increase the valve response time through increased dead time.
| brand | Product Name | Product model | Order No |
| EMERSON | modular | 1X00102H01 | nothing |
| Place of Origin | Marketable land | Imported or not | defects liability period |
| Europe and America | Nationwide and overseas | yes | a year |
| Place of shipment | Delivery method | How to use | Applicable industries |
| Xiamen | Shunfeng Express | Commissioning and installation | Power Plant Steel Plant Cement Plant Shipboard Papermaking |
| Service advantages | Foreign import, goods preparation and supply | Reasonable price and reliable quality | Pictures are for reference only |
| Product features | Primary source of goods, supply by model | After sales guarantee | Chen 1810693-7731 |
Instrument supply pressure can also have a significant impact on dynamic performance of the valve assembly. For example, it can dramatically affect the positioner gain, as well as overall air consumption. Fixed-gain positioners have generally been optimized for a particular supply pressure.
This gain, however, can vary by a factor of two or more over a small range of supply pressures. For example, a positioner that has been optimized for a supply pressure of 20 psig might find its gain cut in half when the supply pressure is boosted to 35 psig. Supply pressure also affects the volume of air delivered to the actuator, which determines speed. It is also directly linked to air consumption. Again, high-gain spool valve positioners can consume up to five times the amount of air required for more efficient high-performance, two-stage positioners that use relays for the power amplification stage.
E-mail:geabbdcs@gmail.com
WhatsApp:+86 15359293870
Wechat:+86 18106937731
Phone:+86 18106937731
Twitter:@Bella_abbdcs
Telegram:+86 18106937731
Skype:live:.cid.4563d9d89ae553bce