Real Life Application for an MCS Magna-Cycle Valve


We have our next recipient of a $50 VISA Gift Card this month. The application described below comes to us through Jim Finn, Pneumatic Product Line Manager for Livingston and Haven in Charlotte, North Carolina. Jim's application is using the MCS version of our Magna-Cycle® Valve (MCS-521-1001-P plus subplate 10-0333). The circuit is used to operate a chopper in a large food processing application. The standard circuit as shown and described below would continuously operate the chopper cylinder as long as air is being supplied to the pressure port of "Valve G" ("Valve H" would have a constant, separate supply source). When the supply is removed and vented from "Valve G" the chopper would cease to function and the chopper cylinder which is mounted with the cylinder/blade downward would stop in either the extended (down) or retracted (up) position. This posed a problem with the startup of the chopping process as the blade needed to be in the up position before the reciprocating motion commenced. To fix this issue and assure that the blade stops in the up or cylinder retracted position, another valve was added as shown in the second diagram below.

As pressure flows through valve "G", it shifts valve "H" and at the same time is metered into air chamber "J" and actuating chamber "F" through flow control "K". Once chambers "J" and "F" are fully pressurized and overcome the magnetic detent setting, valve "G" shifts to the opposite position. This action also shifts valve "H", causing the cylinder to retract and air pressure to build in chambers "M" and "E" through flow control "L". Once chambers "M" and "E" are fully pressurized and overcome the magnetic detent setting, valve "G" shifts back, as does valve "H", starting the cycle again.

Flow control valves "K" and "L" adjust the time delay. Maximum time delay depends upon the size of air chambers "M" and "J" plus the adjustability/sensitivity of flow controls "K" and "L". For the most accurate time control, it is best to have the Magna-Cycle® valve operate a piloted valve as shown. This keeps system pressure fluctuations caused by variations in the work load on the cylinder from affecting the timing cycle.

Modifications and Plumbing for Additional Features to the Circuit

To achieve the function desired, (starting with the blade in the up position), we added our single air piloted, 3-way Mini 1 Valve (M3821301) to the circuit in the area indicated by the small RED circle on Diagram Two on the next page. When "Valve G" is pressurized to start the reciprocating operation, a pilot signal is also sent to the Mini 1 3-way valve which shifts it to allow a straight through flow path from the left side outlet port of "Valve G" to the left side pilot port of "Valve H". This flow path allows a normal reciprocating function to occur. When the air supply to "Valve G" is shut off and exhausted, the pilot signal to the Mini 1 Valve is also exhausted which connects the constant supply to the left side pilot port of "Valve H". This valve is now shifted to the condition that will cause the cylinder to retract and raise the blade. The blade will stay in this position until air is once again applied to "Valve G" and the pilot port of the Mini 1 Valve. When this occurs, the continuous reciprocation (in this case chopping) operation will start once again. Diagram Three shows the way that the Mini1 Valve should be plumbed to achieve the action as described above.

The Magna-Cycle® series features the ability to perform functions that would otherwise create the need for limit valves, limit switches or other types of sequencing devices in a circuit as well as the possible need for electrical circuits as well. They are unique devices featuring excellent repeatability for timing, dwell or force settings. For more information on our Magna-Cycle® valves, please click on this link from our website www.lexairinc.com/valves/h-mag-pr.html.

Thanks again to Jim for sharing this application with us. We hope that others will find it useful. In addition, we encourage all distributor personnel to contribute their applications and earn a VISA Gift Card for themselves.

As always, if you have any questions or need further assistance, please feel free to contact me.

Sincerely,
John W. Jennings
National Sales Director- Valves
Lexair, Inc.

E-mail: jjennings@lexairinc.com
Phone: Office:859-255-5001
Cell:859-338-0008

All Topics