How to Replace a Blown Plunger Seal on Microfluidics LV1 and Microfluidizers

Hi! I'm Rich at New Life Scientific and today I'm going to demonstrate how to change the plunger seal on this LV1. I've done another video showing how to change the plunger seals on other Microfluidics systems and I encourage people that own these systems to learn how to do this because the main plunger seal is your main seal that you're going to have to change multiple times throughout the year. And knowing how to do that really keeps you on track, keeps your production going so that's just something that I want to encourage my customers and people that own these to be able to do this. So you have your service PM once a year and actually I do got all the seals for that and we'll kind of point some of those out but definitely the main plunger seal is your main seal and I've actually got one right over here just to give you an idea. It's a small, super small little guy and you can see this right here. This one's blown so I've already changed it and I've put a new seal in this one and so that I could actually get it running and make sure everything's going before we sell it. But I'm also going to use it as the guinea pig to show you how to do it.


So the first thing that I actually did before we turned the camera on is I actually slid the machine up to the edge and there is a set of feet that lay right in here so that it can support the weight while it's slid up here and you're going to see in a moment why we had to do that. And I didn't want to do it on camera because it almost requires two people sometimes so I have my cameraman Jonathan here to help me do that. Anyways this is kind of how the machine looks right after you've run it and you're like “Whoa. I blew a seal.” “I got leaks coming out down here through these weep holes.” “It's dripping down into the pan and now what do I do?” “I've got to call a service tech or can I change the seal myself?” And that's what this video is about. The first thing that we need to make sure is that when you're cycling this machine that you need to have the machine on the extended so when you're running the machine and I'm assuming you know how to run it already so when you're extending the the plunger, that's where you need to shut the machine off and then release the pressure down. Do not retract it back because it will pull the plunger back up and we won't have access to the set screws that we're going to show you on the next couple steps here. Again, it has to be extended. Shut the machine down. Turn the breaker off in the back. Then you can have the machine slid out and ready to go and then pick up where we're going to start here. We've actually got a syringe mounted here and that's the first thing I'm going to do is just take that syringe off and lay it to a side here. And then we also have this drip pan here and it just slides off here too. So we're just going to get that out of the way and now right away you can see there's a cut out right here and that's because we need that when we pull this head off the plunger. We need that extra room and that's the reason we had to slide this out. What we also need to do is you can see, it's limited on space so we have to remove everything on the side here. We have the check valve here and we have the reaction chamber on this side with the syringe acceptor here. We're going to remove those also.


Over here I have a whole set of tools of everything we're going to need. You can see over here these two are the more- this one especially. This is a custom built tool to remove a part that we're going to get in there. This tool, you can actually buy these on Amazon. It's just I believe a spanner wrench and I just have a screwdriver. Two different size adjustable wrenches here I've got a 8 and a 12 inch and then I have I believe these are 330 and then an 8 inch allen wrenches and I believe that's all the tools we really need to do the main plunder seal.


First thing we're going to do is just screw off the reaction chamber and I'm just going to use my big adjustable wrench and get on there. And once you break these loose, you can just easily unscrew them by hand and I'm just going to leave my syringe converter there. The very biggest thing we got to be careful of – do not damage the end that seals in there. So you just have to be very cautious not to drop it. If you drop it and it damages it, it ruins the reaction chamber. I'm going to set that over here out of the way. Now we have the extension pipe here and we have the check valve here. We're just going to remove- I'm going to remove the extension first and get that out of our way. Again, it's usually just loosening it. And then here we have the collar and then we have the cone which makes the seal. I always like to set the collars about two threads back. We don't want these screwed four threads back. You can see the threads, one, two, three, four. We want about two threads. That's about the right ceiling distance when we put it back on. We're going to set that aside. We're going to take off the check valve and this is where you've got to be really careful because in the check valve are some small components. So I loosen it. I'm just going to hold my hand under it because there's a spring and then there's a steel ball and then there's also- so the steel ball the spring are all in here. Everything come out fine. We're just going to set this over again.


I'm going to just show you what's in here. Here we have the sealing cone and we have a little spring on the back here. Those are so easy to lose because they're so small and they're just set just to the right size so be very careful and don't lose that. What that does is that spring pushes up against the check valve ball just like that. I'm just laying it out how it fits in there. It's just a spring that puts pressure on the check ball and then inside here, it just creates that check valve. So whenever the plunger is pulling back, it's allowing fluid to come in. When the plunger pushes forward it pushes the steel ball, creates the seal so it forces the fluid over into the reaction chamber. That's a simple thing but super small parts that you don't want to lose and that's the check valve assembly. Now we're down to the basic bare bones of just the round part. Now here's where we're going to use our spanner wrench. But before we do anything else, there is some set screws right inside here. One on each side of these holes up here and that's the reason we had to leave the plunger assembly clear down and do not retract it so we have access to that. Now sometimes because of the plunger might spin during the processing, it can spin so that these set screws aren't aligned with the access holes. So sometimes you have to get a screwdriver and that's the reason I brought a screwdriver along just to show you that you can stick the screwdriver in here and there's these prying tabs where you can pry your screwdriver and actually turn and position the set screws. I don't know if we can get a shot in here and see the set screw in there but I'll show you what it looks like if you can't see it there.


So this is what the set screw looks like and it takes the 330 allen wrench and it's black so it's hard to see it in there so you might need to get a flashlight. I've already pre-aligned these. I took my screwdriver and got it ready and I didn't want to do it during the video just to cut time out but I needed to show you what you have to do to line it up. I've got this lined up so I already know that this is lined up. I can go in there and I'm in there so I am ready to just loosen this out and I know that I got it loosened out and I'm just going to actually screw it back in a couple turns. Now I have extra ones here in case I lose these but it's always a good thing to have extra parts in case you do lose them. So again set screw over here same thing now this one's screwed all the way out. Going back in just a couple turns so it stays in there. So now the set screws are out far enough so that I can actually unscrew the whole pumping head assembly and drop it off of the bottom. Now we're ready for the spanner wrench and this is just a big lock nut that we have to just break loose a little bit. You can see the notches. We got the hook and the notch and you put that in there and all it needs is a little bump and that's it. I don't like to actually loosen it too much because I can use this as an identifier of how far to screw it back in place. Just leaving that pretty much just like that because now this is all loose because I've unloosened the lock nut, I can now just simply screw this off. Now as I screw this off I'm going to be pulling the plunger out because we've released it up here with the set screws, the plunger will actually come right out and it'll be the whole assembly once we get it out. I'm just getting kind of down here. We're just gonna start unthreading it until we run out of threads and we can lower it out. Okay. Right there it is.


Now we're just going to pull everything out and here's our plunger and now we need to make sure the plunger comes out with it. Just like that. We're going to take a look at what we just did. You see the little groove right there. The set screws. We're locking this from coming out- I'm sorry on the bottom keeping it from pulling down so loosening the set screws on both sides allow the plunger to come out. And the reason we would take the plunger out is because I wanted to kind of show you all the parts and then how to put it all back together. But anyways at this point, this is what we got the vise for. We're going to need to take the nut off of this side. We're going to need to take some parts off of this side so we're going to actually start on this side and we're going to bring it over. You can notice I've got a rag ready to go here because I don't want to scratch and I've got a vise that doesn't have any grippers on too because I don't want to scratch anything and this is a chunk of steel that's very hard to damage when you squeeze it and the best thing to do is just get it really tight in here. Now I can actually get in here and take off that other spanner nut with my special tool because this will not come out until we remove the spanner nut with the special tool and that's why you can see it's made to fit right in here and slide right in there. So the same thing. I'm just going to break it loose and we're going to spin it around. I can't even get my fingers in there so we just have to use the tool pretty much to get it clear out where I can’t actually get it with my fingers. Now we're at that point where I can get with my fingers and we can actually slide that off. Once that's off, we can just pull this plunger clear out. And because I got that new seal on there, you can see it's got a nice new seal on there that I've just put on it. But I might actually just put another one on it. I've got another new one here and then save this one too. Just to show you everything but we're going to actually set this aside just for a second. I'm going to flip this around. And I'm going to stick it back in here. You might think “Why do you gotta take the bottom off?” Well the way that this seal is built, the only way you can actually- you cannot stick this back in because of the way the seal is built. You actually have to stick the plunger back in and put the new seal on from this side. So it's not a problem to pull it out but to put it back in is the problem. And in all reality, I could have just took this off here. Maybe the seal would have came off. Sometimes they get stuck but sometimes I like just taking them out, taking the seal off, putting the plunger back in and then sticking the new seal on this side. Now we got to take this nut off here and that gives us access to the bottom. Again these are all high pressure fittings that have cones built on them. Special tapers that you don't want to damage. Now we have access to this side here. Here's where we need the other allen wrench because this is what takes that nut off there. Sometimes I have to put this in the vise, sometimes I don't. But looks like I'm going to have to, I can't hold it. I'm going to remove this. Lay that there and I'm going to wrap around this part right here and just get a nice little grip on the vise on that. Just so I can loosen it. I don't want to tighten it too tight and damage anything but just enough where I can break that off just like that. I'm only tightening it enough to get this off because this is the screw that holds the main plunger seal on. There it is. It just slides off the end there just like that and I went and dropped it. I'm going to leave that one on. But you can see, it's so small. You can drop it and of course it blends right in on the floor but like I said I'm going to put a new one in. I've actually got a new one over here so we're just going to go ahead and stick the new one in. I've got all the other seals too but like I said that the plunger seal is definitely the main seal- and here's the part number if you want to see that, you can get them from Microfluidics. You can get them from Dyhydromatics ( that another company that I work with and I'm going to actually put their information in this video because I think their prices are just a little cheaper. It's a sealed bag and you do not want to open the bag until you're ready to put them in because these actually will break down with time and deteriorate just from sitting without being used. So once you're ready to put it in, you can open the bag and I'm going to try to rip it open here. Actually I'm going to get my screwdriver to break it through. It's pretty tough plastic. And I'll have to find my other seal because the other sea. Okay there's the brand new in there. You can see; nice and new, ready to go. I think these are about $70 a piece so they're not real cheap. Like I said, this is a- we've got the seal off here and we don't want to lose this one. I'm going to keep that one there too. I'm going to just take this back out of the vise here. Lay it back over here again and then all these O-rings here. This is just more of a plunger alignment that keeps the plunger when it's moving up and down inside the cavity aligned. And you got some O-rings and then you've got some spacer seals here. These usually aren't really creating much of a seal, just keeping the alignments and keeping the shaft centered. Those are more of a yearly service that needs to be done. Just replace all the O-rings. But what I'm just talking about now is just something that you as somebody running the machine would want to learn how to do because it's one of those things that you're going to encounter and it's just going to be so much easier if you can learn to do this. I'm going to put this back in the vise now because we're actually ready. I'm going to turn it this way because we're going to put the new seal in from this direction here. So these will all slide back in fairly easy by pushing it back in. Putting a new seal on and trying to get it in there, you'll just ruin it. The way it's built - the flanges are flared out. The seal has to be pushed in from this side and then screwed onto this end. So this is fairly easy to just line that back up and I'm going to go ahead and just screw this back in. And we're going to flip it around and tighten it after a bit but all we're wanting to do is to get this shaft up here as far as we can. You can actually see it right in there. You can see the end of it and you can see how it's going to receive our new seal and our screw. Now, it's very important that you put this on the right way. It needs to go on there and it needs to fit with the stainless steel spring that's built inside it to push the seal outward. This is where it's probably going to get the trickiest. Trying to keep that on there and get your screw right up in there. Keep this plunger fitted in there and just get that started enough there. And making sure that seal is starting and it's centering and it's going in. This is where we're just going to slowly snug it just a little bit. What I like to do before I tighten it is I like to just pull the plunger back now. So that we're actually going to pull the seal back in. So now it popped it back in and now I feel comfortable tightening it at that point. The reason is if I try and tighten it and push, I just feel like it's safer just to have it snugged up. Pull the seal back in and then finish tightening it up. Again, it's a little bit hard to hold this and tighten this here so what you can do is while it's in here is you can get perhaps like a channel lock and just snug it up by holding it there. Or since I didn't bring a channel lock, I'm just gonna quickly- I'll snug that up a little bit later. But I think you get the idea. You need to really hold this and then snug that up there. I think I'll better go grab a channel lock. Be right back!

I went and grabbed some pliers and I'm going to go ahead and wrap this and hold this here so that I can get this snugged up in here like I wanted to. There we go. I don't want to do any damage to the edges here although this doesn't interfere too much. It's just a collar that holds the set screws so it's really not- like if you do ding it a little bit, it's not super important. But the main steel plunger assembly, you can't get any dings, chips or anything in that. That's extremely important. We have the new seal put in and all we have to do again now is install our plug here. Our access plug. Screw it back on here. We're going to tighten that up. Tighten my vise up just a little bit more where I feel comfortable. We got that and now- brand new plunger seal in there. The only thing we have to do yet is I'm going to flip it over and I'm going to tighten this collar on this over here. The reason I'm going to flip it over is because I don't think that I can spin my wrench around unless I have it out here.This is where we're going to go ahead and pull this out. And we got the special spanner wrench and stick that back in and we're just going to spin this back on. That's the reason I'd flip it down because this handle would have hit the table on the other side. Kind of like it is a little bit right here. Again, we're going to give it a little bit of a snug. Take it out and voila!


It's completely ready to go back in. If you want to go further and change out these parts, they all come in a rebuild kit. All the O-rings. All those are easy to change and even all the other seals you've seen. All those come in a PM kit. All those seals come in a PM kit. But like I said, these seals last so much longer than the main plunger seal. That's why the focus is on that main plunger seal to keep us up and running. Once you got that out, everything is ready to go back in over here. It's all about kind of fishing your way up. I can see through this access hole here, I can see where it needs to slip in there. It's just finding it and it's just pushing, pushing, spinning, and remember we don't want to move that because that's our set point. And right there. That’s our stopping point. We got the check valve here. Before I tighten this, I actually like to get some of these on. That way I could see if it's running parallel with the machine. Sometimes, if you get this tight and it's not running parallel then it just doesn't look right and you might not be able to get your syringes on right either. At this point, I don't tighten this. I get the reaction chamber. Just be very careful of that cone tip. Just come in here. Just screw it back in. And we're going to grab my wrench and just a nice little snug there.


Here's where we have to be careful because we have our check valve. First thing that goes in is the steel ball. The next thing that goes in is the spring. Drop it in like that. So you should be able to go like that. Bring it over here and screw it in without losing any parts. We're just snugging this up. I'm looking at my two threads on my collar. Put the nose in leaving this angled out here. Snugging that. If you do get a little bit of drips, you can snug it up a little bit more. I would rather work my way up to it rather than over tighten it. I need to adjust this a little bit here because it did go back a little bit further. I'm gonna have to hold this and grab my other wrench here. Loosen this just to bring it back. That one doesn't swivel. So we'll just have to bend it there. Now, we can kind of use this as judging being parallel with the machine now. That looks good to me right there. So that's where I want to tighten this collar up. This is where I'm just going to grab it again and sometimes, when you go to tighten up, it actually wants to move this. So then I'm going to kind of counter move it backwards and do my final bump tap. Now it's locked. In it's nice and parallel. Everything is again ready to go.


You got your syringes. I didn't have to use any of these. And the last thing we're going to do is go back in and tighten our set screws up there on each side. Plungers all the way up. We're just going to tighten that one. Come in on this one. Tighten that one back up. Don't forget to tighten that because when that goes to extract, it won't pull it without those being tightened so that's very important you remember that. And it's just sliding this back on over top again here. Then you're ready to go again. You've got your syringe. We can now turn the machine on. And we're going to go ahead and reset the jog. I'm going to go ahead and retract. Let's pull the plunger up so the set screws are tight. That's pretty much it! You're ready to run again. It's got a brand new seal in it and I need to find the one I dropped on the floor.


If you got any questions on this machine in particular or anything else, just give us a call here at New Life Scientific and hopefully we can answer them. I appreciate you watching and I'll see you on the next one.