Why would my pump leak here????

Dunno what your pumping. Note: grease fitting. If food grade, need to use food grade grease (any grease will do if it will not interact with product being pumped). There is USUALLY two seals at that location and the grease is used as a low pressure sealant to keep product from leaking out of "weep" hole. If that hole has threads in it, should probably have a set screw that was left off when built or vibrated out. Kinda hard to tell with product in hole. If hole hase screw in it, means pump seal is failing.

 

http://www.youtube.com/watch?v=RjpcF3YZaLs
That is a video of how your blackmer pump works, I'm just guessing that your "student" over reved the pump (thick liquid? I don't know what you are pumping) and he created too much pressure inside the pump and pushed product past the seal and out the weep hole. If it stopped leaking when you slowed it down, probably no damage, but it it continues to leak its gonna need a seal. Also if the pump was not properly or compleatly cleaned after the previous load, hardened or crystalized product will cause a temporary leak. At the end of the video they increase pump RPMs and the pressure goes up more than the GPHs, in your case causing a seal leak. If the product leaking in the pic hardens or "sets up" the weep hole is now plugged and will mask any future problems, and should be properly cleaned.

 

I think you can get a seal kit for those pumps...crap I wish I remembered the name of the company who made those seal kits.

 

You said it started to cavitate...that noise may have been the paddles inside the pump jumping and tearing.

Blackmere works best on thinner stuff; we used Stainless steel Blackmere & Walkashaw pumps for pharma grade pure ethanol and denatured ethanols and solvents.

Thick products and overspeed will mess up the paddles. That looks like a 'weep' hole to let you know the seal is failing. As stated above rebuild kits are available and these pumps are rather simple to overhaul.

Don't overspeed a blackmere!

Ranger makes a copy of the old Roper pump and they are better suited to pumping thick stuff. I used to load an oil additive from a heated railcar pushing it thru a 5 micron filter pack to load. The shipper used braided stainless steel hoses to make sure it would not burst a hose as it was so thick.

The one customer would off load about 1/2 into the kettle and reload it as hot 'cutback' solution so it would not thicken in their lines as we pushed it to the storage tank.

Blackmere is a good pump but it will not stand up to abuse like the old ropers. you need to open it up...

 

That's what I call the pisser hole. Almost every pump has one. It let's you know when the shaft seal fails usually from a bad bearing that starts to wobble the shaft a little and makes the seal hole sort of egg shaped. If that's the tenth pump look at what's driving the pump and the bearing(s) on it.

 

When you replace the seal they have a hi temp seal option. You might want to consider .......... Blackmears can do heavy thick products......



Brass veins , are the key. This pump is on liquid asphalt... 5 years old, some days does 3 or 4 loads . I have put 2 sets of high temp seals in .....

Not 2 bad.... I do think The big 3 " roper is better .