Hi, I’m Todd with BlastOne here in Columbus. And today I’m going to show you how to replace a TeraValve seat on the bottom of the base.
So, two of the major symptoms that you want to watch for when you’re dealing with a bad seat are going to be airflow without the deadman being initiated. That should never really be happening. And also, if you are initiating the deadman and right away you’re chugging a bunch of abrasive out of the blast hose, and then it starts to even out to what you have the metering valve set to, those are both signs that the TeraValve seat is definitely going to need to be replaced.
A couple of the causes of those symptoms would be positive or negative differential pressure. Whether you have too much pressure in the pot, not allowing air through the push line to go through consistently, or the reverse, you have too much air going through the push line and not enough abrasive falling at the correct rate. Both of those issues will inevitably cause that seal to wear faster than it should.
The valve seal that we’re actually after today is all the way at the base of the TeraValve. If you look down here, you can actually see there’s a very dark purple urethane seal right there. And that’s what we’re going after.
So you can see the whole plunger system. You can see the dump channel right here being plugged up. The TeraValve would actually mount directly like this. So the air would be coming down. No air should be escaping up because there’s a seal right here on this plunger that you can see.
And if there is abrasive, or if there’s air without the signal line initiated coming through still, it could be that the actual TeraValve needs rebuilt. But today we’re just going to focus on the valve seal on the bottom.
So I have a nice and dirty TeraValve right here, actually off of one of our MistBlasters. All we’re going to do is remove these four bolts. Right here are 7/16-size bolts. So you’re just going to remove those, and then that’s going to give you complete access to the bottom of the TeraValve.
And once you have all of these off, you can see sometimes there will be excessive wear. This orifice will actually be oblong, or it’ll have a little oval shape to it. This one doesn’t necessarily look that bad when it comes to the orifice size. It’s still good, but as you can tell from the inside of it, there was a point at which the abrasive was still able to get through, even though this orifice is still the same size, and cause a lot of extra wear on this base.
So once we get that, we’re going to get access to the actual seal on the bottom, and it’s seated in there really nice into the machined slot that we have. With a wrench or a screwdriver, we’re going to just pry this out.
So once we have that off, you’re going to take your new one. You can see it’s very nice and flat on the one side, the side that actually goes down towards the base. And then if you flip it over, the nice beveled edge that they give you to go around the plunger is nice and symmetrical, and there’s no wear patterns on the inside or anything like that.
So once we go to reinstall, you’re going to want to discard the old ones so you don’t mix them up because they look very similar. And when I say beveled, there’s actually an angled edge that’s on the top of the TeraValve seat. That edge you want to face up towards the mating part of the valve.
So you’re going to take that. You’re going to seat it right here after you make sure it’s all clean and doesn’t have abrasive in it. You’re going to take the beveled end up and fit it right into the machined slot that it has for it.
So once you have that set in place and it feels secure, you’re just going to take the 7/16 bolts and nuts that you took off and replace them. And each of these screws is going to have a washer on both sides, and then the nut on the one end.
It’s easiest for access to put the nut on top and the bolt coming through the base going up, so that you can get a wrench on the one side and you can get an impact, or if you only have sockets, you can get them on the other end. And you don’t need to worry about the distance that you have right here between the base of the valve.
And normally, with seals and gaskets, you do want to make sure that you evenly tighten everything. So once we have these finger-started, we’re going to take our wrench, hold the top.
And that’s how to replace the TeraValve seal. So if you have any more questions, you can click the link below, and we can find you somebody that can get you some answers.
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