De Filters Are Dangerous: Please Read This Story!

[dereknobleluke]

I have been on pro brewer asking questions, but one thing I would like to share with other DE operators is the one really dangerous story I have....

About 5 years ago I was scavenging the rest of a 40 bbl run, applying about 50 psi on top of bell. When the beer was almost out, the bottom clamp's threads gave way, causing the bell clamp to open up rapidly. This caused the 50 pound bell to launch off the filter, miss my head by about a foot (I was looking down at the sight glass for bubbles), traveled up to the 24 ft ceiling (missing electrical, water, and sprinkler lines), puncture the roof, keep going through the roof of the building, and landed in the parking lot on the other side of the building. Luckily it was 6 am, so no one was hurt. The lower 5 disks of my filter looked like pringles potatoe chips (they still do work mind you...).
I couldn't hear for about 5 hours due to the sonic shock. People have said, "well you shouldn't have been using that amount of pressure". It wasn't the pressure: as the bell rode up the support rod and hit the top "catch" of it, the bearing wheel allowed the bell to "rotate" about 5 degrees. With all that rotation force now behind it, the bell was then "flung" off the filter's main support frame, much like a baseball gets "flung" off pitchers fingers. It broke 12 guage stainless that was welded to the bell cleanly.

Once I retrieved the bell, I literally bounced around on top of it to make it round again (it became a tad eliptical...), bought a new clamp, new pressure relief valve (the old one still works and triggers at 80 psi, new one I got for 50 PSI), new pressure guage, and new bottom gasket. And to be honest, the filter has never worked better....

Filter parts, shipping, and phone calls to Italy: $450
Repair to roof: $4500 (yes, it was that much)
Able to still hear, talk, and write things on probrewer b/c I didn't die: priceless

DE FILTER OPERATORS BEWARE!!!

[froptus]

Wow! Scary story. I've been opertaing DE filters for almost 15 years now and fortunately haven't had any incidents. I've had many filtrations where the pressure got up to 50-60 psi, which is perfectly fine according to the filter manuals. I've also had a few where the pressure has gotten as high as 80-90 psi. Once back when I was a rookie I let the pressure get to 100psi. I figured as long as the beer was still moving, I'd let it go. Then I decided to check the pressure specs in the filter manual. It said not to exceed 85psi. I immediately shut it down. I guess I got lucky on that one.

I'm glad no one got hurt.

[dereknobleluke]

if the filter is full of beer, not that bad. If filter is full of pressurized gas, thats when stainless rocket ships are born. I've heard of brewer whose relief valves were not installed on 10 bbl tanks. Further unregulated CO2 went into the vessels. He got a phone call upstairs and left CO2 on both of them. One had beer in them, other one didn't. When the doors went concave to convex, one tank just spilled a bunch of beer. the other tank...well, its door broke part of a cement block wall and the tank body traveled backwards about 4 feet until it hit the side of the cold room. Everything on shelves in the cold room went to the floor, glycol lines burst...a real mess. Pressurized gas=bad when a seal goes. Pressurized liquid=well you can't pressurize a liquid....

[Laughing Dog]

here is a wonderful tip
if helping someone else that was running the DE Filter clean the DE filter make sure all the pressure is off the dome before pulling the safety pin then clamp latch!
I did not !! result quick trip to ER and emergency surgery on my left hand 4 inch ripped gash to the bone and shattered my wrist maybe one more surgery
The lesson from this? Write out all procedures and make sure everyone does everything the same way EVERY TIME ALL THE TIME DON’T GET IN A HURRY TO GO HOME AND SHORTCUT ANYTHING EVER

Fred
Laughing Dog Brewing

I still have issues with the left wrist and a possible surgery later on
as stated in this thread DE filters can be killers be careful

Fred

[gitchegumee]

Technically you CAN pressurize a liquid (think hydraulics), but the pressure is nearly instantly relieved upon expansion. Liquids don't compress very much. Gases compress very, very well and can be used to store lots of energy. So when a DE bell full of pressurized liquid releases, there is very little stored energy. That's why tanks are hydrostatically (read: with water) tested and never tested with gas. The first few drops of liquid to leak relieve the pressure. That said, I use CO2 to push the last bit of beer through the filter. It's always fairly low pressure as I just keep enough pressure on the filter to keep my beer from foaming. Breweries are not inherently dangerous places and DE filters are less dangerous than automobiles; you just have to keep your wits about you, work thoughtfully and carefully, and use well written SOPs to do your work. Good luck and work safely!