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Such as a PILOT valve

111- With the Skinner unbalanced design, and a fixed orifice, changes in air pressure affect the shifting forces of the valve. At 20psi the spring force is greater than the pressure force.

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Such as a PILOT valve

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  1. 111- With the Skinner unbalanced design, and a fixed orifice, changes in air pressure affect the shifting forces of the valve. At 20psi the spring force is greater than the pressure force.

  2. 112- At 75psi, the pressure force overcomes the spring and off-seats the valve. With this unbalanced design the forces to shift the valve change as the air pressure changes.

  3. 113- With the Skinner fixed orifice design, different orifices are required for different pressures. To make a valve rated at 150psi the orifice must be greatly reducded. Such as a PILOT valve

  4. 114- This is the Skinner orifice for the low pressure, 50psi valve. “CLICK”

  5. 115- This is the orifice for the high pressure, 150psi pilot valve. The orifice is smaller, because of the high pressure forces trying to off-seat the valve.

  6. 116- Here, looking at the bar graph, you can see we have reduced the pressure forces, by reducing the orifice area, allowing the valve to remain on-seat.

  7. 117- With the smaller orifice the valve can now be rated @150psi and used as a low flow pilot valve.

  8. 118- With the Mac BALANCED design one large orifice is used for all pressure ranges.

  9. 119- Here, we can see the flow differences, between balanced and unbalanced designs. The Skinner 50psi orifice, flows 4 times less than the Mac design.

  10. 120- The Skinner 150psi orifice, flows 10 times less than the Mac design. This is the pilot valve used for most of the competitive pilot operated valve designs.

  11. 121- The Mac valve not only flow 10 times more, but the larger orifice design, is more resistant to contamination.

  12. 123- With a long stroke Skinner solenoid our shifting forces are low.

  13. 123- With Mac’s short stroke solenoid, our shifting forces are HIGH. Like holding magnets close together.

  14. 124- Solenoid & spring forces are related. With a long stroke solenoid and low shifting forces,

  15. 125- we must use a weak spring.

  16. 126- With a short stroke solenoid our shifting forces are high.

  17. 127- Therefore we can use a strong “beefy” spring.

  18. 128- With an unbalanced design and fixed orifice,

  19. 129- changes in air pressure will affect the shifting forces of the valve.

  20. 130- Even causing the poppet to be off-seated.

  21. 131- With Mac’s BALANCED design,

  22. 132- changes in air pressure do not affect the shifting forces of the valve.

  23. 133- The unbalanced design is susceptible to air line contamination, because of small orifices.

  24. 134- and an exhaust path through the heart of the solenoid. When operating with AC voltage, the in-rush current, can cause coil burn-out, when it doesn’t complete it’s stroke.

  25. 135- Mac minimizes resistance in the valve body, by wiping contaminates, low friction & a balanced design.

  26. 136- The wiping action is similar to a windshield wiper, not letting contamination build in the valve bore.

  27. 137- With the Skinner unbalanced, fixed orifice design, different orifices are required for different pressures. This is the 50psi orfice.

  28. 138- With the smaller orifice the valve can be rated @ 150psi and used as a low flow pilot valve.

  29. 139- The Mac valve not only flows 10 times more, but the larger orifice design, is more resistant to contamination.

  30. 140-Mac produces a valve with high shifting forces on each end and a low friction body, that doesn’t compromise these forces. Valves that don’t stick.

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