Type: Adjustable Auto-Cycling
Vacuum: Electric Pump
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Understanding How It Works
(Continued thanks to Jon Dake for assistance with this portion of the vacuum press)
The Project: EVS system is very easy to build and only requires a minimal understanding of the basic components and the purposes they serve.
- Vacuum Pump: This is the heart of the system.
It removes air from the vacuum bag allowing the atmosphere to exert pressure which results in a clamping effect upon the veneered panel.
- Vacuum Controller: If the vacuum pump is the heart, the vacuum controller is the brain. This critical piece controls the pump and the electro-pneumatic valve (Mac valve).
Since no vacuum system can be perfectly sealed, a small leak is always possible. When the vacuum drops, the vacuum controller turns the pump on and engages the Mac valve causing it to direct the flow of vacuum from the pump into the main system.
- Mac Valve: The Mac valve is a gateway for vacuum flow. It directs air flow to either the main reservoirs when additional vacuum is needed or to an exhaust port when the system cycles off. This exhaust is simply a removal of vacuum from the pump so that it can easily restart on the next cycle.
- Vacuum Reservoirs/Sub-Reservoir: The main reservoirs in the system hold spare vacuum just like a rechargeable battery. These reservoirs prevent the system from constantly cycling on and off by providing additional vacuum buffer. The sub-reservoir is a small holding tank of free air that allows the pump to achieve full RPM when starting up without back-pressure against the pump intake port.
- Check Valve: This simple device prevents air from flowing backwards into the pump during the initial stage of the recharging cycle. When the pressure in the sub-reservoir exceeds the pressure in the main reservoirs, the check valve opens and the vacuum from the pump begins filling/refilling the main reservoirs.
If you are thinking that it would be much easier to simply attach the vacuum bag directly to a vacuum pump and turn it on, click here to read more about why these parts are needed for this system.
Up Close and Personal: A Good Look at the Vacuum Press
Place your cursor over the picture to label each part.
If you read the instructions carefully, you'll find that this system is surprisingly easier to build than previous versions of the press. Each part of the system has detailed instructions. The total average build time is now under 5 hours (down 30% from the previous version). Here's a quick look at how it all goes together.
- Read the full instructions and review the parts list.
Time: 45 minutes
- Build the manifold - This is an assembly of brass hardware that connects and centralizes the main parts of the system.
Time: 25 minutes
- Build the sub-reservoir manifold - Another quick assembly of brass hardware that connects the pump, filter, and Mac valve together.
Time: 20 minutes
- Build the PVC reservoirs - Two reservoirs are used in the system to hold spare vacuum. A smaller sub-reservoir is also built to provide "free" air to the vacuum pump when it cycles on.
Time: 60 minutes
- Make the carrier - A couple of pieces of 3/4" plywood make a simple carrier for the system.
Time: 30 minutes
- Assemble the system - This step is an easy one. It's as simple as putting together all of the previously assembled parts.
Time: 45 minutes
- Wire the system - You don't need an electronics degree to successfully wire the system. Follow the instructions and your system will be up and running before you know it.
Time: 15 minutes
- Testing and adjusting - Test the system for vacuum holding and adjust the cycle pressure.
Time: 15 minutes
Please note: The build times above are based on average users with a good understanding of how the system works. I highly suggest reading this article from beginning to end before you start building your system so you have a thorough understanding of how the vacuum press parts work together.