To be able to drain the table for maintenance and for times when we are not using it to limit fluid loss due to evaporation we put drains in the table.
The drains are ¾ pipe fittings welded into the base of the pan. We left a lip of 3/16 of an inch on the top side of the table. We did this for a couple of reasons. When the dust and debris from the cutting settles
To the bottom of the pan after cutting we wanted to keep that debris out of our sump system. The 3/16 inch lip on the top in theory will keep that layer of debris on the bottom from flowing into the sump. We will not drain all of the liquid with this but it only ended up leaving about 8 gallons of liquid in the table. Which would be heavily contaminated anyway and could easily be removed with a shop vac.
We installed ball valves with flexible hose to allow us to easily turn off the drains and easily disconnect the drain tube for when we need to remove or service the sump drums.
We have valves at the base of the drain hose as well to allow us to close off the drums and remove the drum cart for service. The upper vent bungs have a valve on each drum and a common exhaust and fill pipe. The common pipe makes filling much easier and even. The fill line uses a standard air fitting and a regulator to limit the fill pressure. We found we only needed 5-10 psi to refill the pan from the drums. We later installed a low pressure gauge to monitor the pressure in the system.
This picture shows the
Pressure gauge that was installed after the first test to monitor pressure in the system.
We started our test of the system by filling the pan with water. We checked for leaks and were pleased not to find any. We then opened our drain valves and our vent line.
The drain process for the approximately 80 gallons was a little slow. It took about 15 minutes to drain the table. This is due to using the small diameter drain and vent hoses. 15 minutes to drain is fine for us. So were going to leave it alone. We don’t plan to drain on a daily basis so this wont be an issue.
We let the system sit after draining and checked for leaks in our sump. No leaks! We used a shop vac to remove the rest of the water from the table to see how much was left due to our 3/16 inch risers on our drain tubes. It only ended up being about 8 gallons which was fine for our use since it would be removed with a shop vac any ways during cleanings.
In our first refill test our pressure regulator was did not regulate down to 5-10 psi and we did not have a low pressure gauge so we did not know how much pressure we were putting in. The bulging in the drums told us to back off the pressure. We installed a low pressure gauge and kept the pressure in the 5-10 psi range and found it was plenty of pressure to fill the table. It took about 10 minutes to fill the table which for us was plenty acceptable.
We let the system sit pressurized over night to check for leaks in the system.
We found a small leak in one of our drums at the bung fitting. This was easily fixed by tightening the bung. We applied some RTV to ensure leak free connections in the future as an added safety measure.