"What is direct acting and reverse acting? All these terms will be explained in detail in this clip. How do we identify whether the actuator and valve body is reverse acting or direct acting? Again, all these methods will be covered in the video. The Air-to-Open control valve is where the valve body seat is closed when the instrument air is supplied to the actuator while the Air-to-Close control valve is where the valve body seat is opened when the instrument air is supplied to the actuator. Occasionally, you mean heard the terms such as Air-to-Retract or Failed Close instead of Air-to-Open control valve. Sometimes, the terms of Air-to-Extend or Failed Open are used instead of Air-to-Open control valve."
The actuator is direct acting when the spring acting on the diaphragm is either in compression and pushing up against the diaphragm from below, or is in tension and pulling the diaphragm up - in this latter case the spring is placed above the diaphragm. In a reverse acting actuator the opposite is true - the spring is either in compression and pushing down against the diaphragm, from above, or is in tension and pulling the diaphragm down. So there are actually four of these diaphragm actuators possible, not two. This point is important because the actuator can be direct acting even with the spring above the diaphragm, if the spring is in tension rather than compression, and likewise it may be reverse acting even with the spring below the diaphragm. It is the position of the spring as well as whether it is in compression or tension that determines whether it is direct or reverse acting, not just the position. And technically, the valve body is direct acting when the plug pushes down on the seat, and reverse acting when it pulls up against the seat. These valves can be installed on horizontal lines like you show in your video, as well as in vertical lines, so again the point is important to make, as the plug in a direct acting valve body will not always be above the seat, nor below in a reverse acting valve body - picture one of these valves flipped 90 degrees - the plug would be horizontal to the seat rather than above or below in this case, so the above explanation is the technically correct one.
You can send me your email as I can not post the work related videos in RUclips due to company policy. Previously, I have removed all the hands-on videos to avoid issues. Nowadays, i produce only theory related videos.
"What is direct acting and reverse acting? All these terms will be explained in detail in this clip. How do we identify whether the actuator and valve body is reverse acting or direct acting? Again, all these methods will be covered in the video.
The Air-to-Open control valve is where the valve body seat is closed when the instrument air is supplied to the actuator while the Air-to-Close control valve is where the valve body seat is opened when the instrument air is supplied to the actuator. Occasionally, you mean heard the terms such as Air-to-Retract or Failed Close instead of Air-to-Open control valve. Sometimes, the terms of Air-to-Extend or Failed Open are used instead of Air-to-Open control valve."
Thanks, well explained.
Thanks to you too.
Fantastic Explanation, far more better than so many useless Indian guys Writing English subtitle but Kajra Language
Thanks for your compliment ! Actually, my English is very poor and my technical also not good. I am still learning from everyone too. Thanks again.
This video is so helpful and your english is quite good
Thanks for your compliment! Actually, my English is poor and grammar also wrong....lol.
Thank you
You are most welcome!
The actuator is direct acting when the spring acting on the diaphragm is either in compression and pushing up against the diaphragm from below, or is in tension and pulling the diaphragm up - in this latter case the spring is placed above the diaphragm. In a reverse acting actuator the opposite is true - the spring is either in compression and pushing down against the diaphragm, from above, or is in tension and pulling the diaphragm down. So there are actually four of these diaphragm actuators possible, not two. This point is important because the actuator can be direct acting even with the spring above the diaphragm, if the spring is in tension rather than compression, and likewise it may be reverse acting even with the spring below the diaphragm. It is the position of the spring as well as whether it is in compression or tension that determines whether it is direct or reverse acting, not just the position.
And technically, the valve body is direct acting when the plug pushes down on the seat, and reverse acting when it pulls up against the seat. These valves can be installed on horizontal lines like you show in your video, as well as in vertical lines, so again the point is important to make, as the plug in a direct acting valve body will not always be above the seat, nor below in a reverse acting valve body - picture one of these valves flipped 90 degrees - the plug would be horizontal to the seat rather than above or below in this case, so the above explanation is the technically correct one.
Dude, thanks for laying that out! Your clear and informative explanation is really excellent. Appreciate it!
nice
Thanks !
Hello sir kindly send me positioner postions adjustment video
You can send me your email as I can not post the work related videos in RUclips due to company policy. Previously, I have removed all the hands-on videos to avoid issues. Nowadays, i produce only theory related videos.