|BIG NEWS!!!!!! |
We are very excited to add Tammie Hughes to our staff in Chelsea, AL. She will be doing inside sales, warehouse work, and helping with some clerical duties. She is a mother of two, and the wife of an Army man. We are very excited to welcome her to the VAC family. Her email address is listed below, feel free to send her an email email@example.com
Recently we had a field installation that reminded us about something that sometimes gets defined wrong. The issue is loss of supply air to a positioner. On a spring return actuator application, the springs take over and this is a non issue. However, on a double acting actuator there are two possible scenarios when dealing with loss of air supply. The first scenario is when supply air is cut instantly. When this happens, the double acting actuator stays in place. The second scenario is when the compressor fails and there is a slow drop in air pressure. In this scenario the valve will eventually go to the zero point when the line pressure drops below 20 psi. To prevent movement in the valve package on loss of air supply we would recommend a pneumatic lock up device, this device is placed between the positioner and actuator. (pictured below) When the air pressure drops below a set pressure the lock up device activates and locks the air in the actuator. When the pressure in the air supply goes above the set pressure the device will then allow the positioner to modulate the valve as normal. Please give us a call if you are interested in buying a pneumatic lock up device or need more information on it.