Post Webinar Questions
All right. Thanks, Wade. As we mentioned before, if you have any questions, there is a little question bar on your GoToWebinar toolbar. Please feel free to type in your question from there, and we'll get through as many of them as we can. Trying to be, of course, respectful of your time. One last thing to add, though, Wade mentioned the onsite training. To further clarify that, an onsite visit basically is when a TPC Trainco instructor comes out to your site to actually do a customized training for you. And one of the advantages in the pump's world is that the instructor can then take a look at your equipment specifically, tailor the training specifically to your equipment, and help you understand any issues or problems that you may be having, again, specific to your equipment, so a good benefit for folks that have a need for an onsite visit. But let's get through some of these questions, Wade.
The first one we have is, "Can you explain the maximum clearance needed for a submersible pump?" It's a little bit off the topic, but if you could go through that briefly, that'd be great.
Wade: Actually, that's really not off the topic. I've run into that question many times, particularly in an application where they're using a multiple-state submersible in a weld jacket. We used to get that call a lot, and it's kind of interesting, because minimum clearances are actually specified by the individual manufacturers. But typically I tell people, "If you got a 4-inch diameter submersible pump, you need to put in at least a 6-inch casing, and you need to have so much water on top." Now, as far as the submersible pump that's going to be used to, say, be thrown in a small location to lift water out of an area where you got a drainage problem, that's going to be based on how many gallons you anticipate, because you don't want to run the pit dry.
The idea of having a clearance around that pump and motor is you're using that liquid or pumpage to cool that motor to keep it from overheating. So it's important that you have a certain amount, and typically I would refer you back to the specifications of the individual manufacturer, because it differs from pump to pump.
All right. Thanks, Wade. Again, want to just remind you, if you need a copy or want a copy of the presentation in a PDF form, you'll receive an email at the conclusion of this webinar. Please just respond to that email, and I will get a copy of the PDF out to you shortly. Moving on to our next question, "On new installations of pumps with moving water, is it co-compliance to install a VFD weight?"
Wade: No. Not particularly. VFDs are typically used in an application like that on water for if your pressure or your flow demands in your system vary at point to point during the operational times that you're using the pumps. VFDs are becoming more prevalent in heating and air conditioning systems in buildings for circulation pumps for chillers. I used to tell people a long time ago when the Earth was green and I was a lot younger, "Chiller systems in big buildings would have a valve in there. I used to call it the wasting valve, because what it does is it wastes a certain amount of fluid back to the other side of the pump again and doesn't sent it to the building, it loads on the building chain.
In other words, as the temperature of the day goes up, the requirements to cool the building become greater, and as the temperature goes down, it goes the opposite way. So, keeping that in mind, VFDs are actually becoming the preferred way to control pumps throughout the different types of curves, if you would, or the different load conditions.
All right. Thanks, Wade. Another question relating to submersible pumps, "Have you ever heard of sewer water in a full wet well creating cavitation in a submersible pump?"
Wade: Absolutely. That typically occurs when you've got a problem with trying to pull too much solids through there. You might find in a submersible, if you don't have something to dice up or slice up the incoming solids, it can actually get caught crossways in the inlet area, and cause a low enough flow area to cause the pump to cavitate. So typically it's a mechanical issue where you've got some kind of blockage going on.
Thanks, Wade. Do you have a recommendation on how often someone should do maintenance on their pump system?
Wade: Oh, that's a moving target. It all depends on the application, how long the pump runs. Does it run 24 hours a day, 7 days a week? Does it only run eight hours a day? Does it only run two hours a day? Does it run an hour a week? All those kind of things play into it. A good suggestion is go on out there, and there's a little book out there that I like to refer people. It's called "The Industrial Multi-Craft Mini-Reference Book," and that book is actually produced by Audel. And it's a little handy, I call it a desktop information reference guide.
It's roughly about $10 to $12 on Amazon, and it's really quite a fascinating little desktop tool that you can use. And it talks about how often I should re-grease my pump based on the size of the bearings and how long it's running in hours. So, you know, that's one of those loaded questions.
All right. Next question is, "If my seal water is entering cool and exiting very hot, is my seal water flow rate too slow?”
Wade: Again, that's going to depend on the type of the pump and what type of seal that we're operating with. If you're operating a patch stuffing box, then my suggestion would be is, yeah, you don't have enough flow going on. The other thing that you got to take into consideration is, "What am I pumping, and how hot is the fluid that I'm pumping?" Because that would be an indication that your pumpage or what you're pumping is actually being mixed with your drainage. So that's one of those open questions. It's tough. It's more specific to the application.
All right. Next question goes back to the use of VFDs on pumps, and the asker wants to know, "When might it be inappropriate to use a VFD on a pump?"
Wade: Well, if you're using a VFD on a pump and you're only running the pump at, say, set RPMs. In other words, you're using the VFD, and you're running it at 1,750 or 3,500 RPMs, then it's really not being used as a VFD. But if you want to minimize your voltage dips in your system, a VFD can be used to do that as what we call a soft start, but you might be wasting your money on a VFD if you never change the speed.
All right. Wade, a couple questions ago you mentioned a specific book that was helpful in terms of scheduling a troubleshooting program and maintenance program for your pumps. Can you simply restate what the name of that book was again, please?
Wade: Absolutely. If you go to Amazon, and I hate to tell this to people, you know, there's particular websites. But if you Google, "The Audel," A-U-D-E-L, "Industrial Multi-Craft Mini-Reference book," and the author's Tom Beaver Davis. And if you Google that, you'll find that's a very handy little book. Like I said, I think Amazon has it for like $10. But it has a lot of those little tiny questions that pop up when you're trying to do work on small pumps and stuff like that and big pumps.
So it's kind of a handy little reference guide to tell you when you should do things. The other thing in that presentation, a few slides back, I talked about lubrication. The website that's operated by a company called Noria, they specialize in machinery lubrication. That machinerylubrication.com has got a lot of little YouTube videos out there to tell you how you should do things, and that's going all the way back to slide 16. I have it highlighted in red there. You can actually go to that machinerylubrication.com website, and you can actually sign up for their monthly periodicals, and you can get daily or semi-weekly little blurbs from them about how you should do things and stuff like that. It's a pretty handy little website.
All right. Wade, the next question says, "I have a spare water pump. What is generally the best way to store it on a shelf?"
Wade: Oh, that depends on what configuration the pump is. Is it a large pump? Does it have sleeve bearings? Does it have regular bearings in it? All those kinds of things come into play. Now, that being said, if it's a small pump, a fractional horsepower pump, you should probably occasionally two, maybe three times a year, you know, stick a little tool in the inlet of it and kind of give it a little spin around and re-establish the lubricant around the bearings. That pump shouldn't be stored someplace next to other machinery that's vibrating violently or causing the shelf to have a little bit of vibration to it, because that vibration can cause problems in the pump itself, not so much the pump, but in the pump bearings.
All right. Thanks, Wade. Next question, "What should I look for when trying to size centrifugal pumps in parallel? And what about positive displacement pumps in parallel?"
Wade: Well, first of all, positive displacement pump in parallel and non-positive or centrifugal pump in parallel are two completely different animals. You've got positive displacement pumps in parallel. What you're doing is you're matching flow and adding head. So, in other words, as your flow requirements change in your system... In other words, I always use the example, if you can imagine at a petroleum refining facility or petroleum dispensary, you've got these what we call truck racks where they pull the trucks in and fill the tankers up with gasoline, diesel fuel, or whatever they're carrying. Those will actually have pumps in parallel in the system. And what they do is they're based on what the demand of the system is. So as the pressure drops in the system, more and more pumps will come on to keep the pressure up in the system so it matches the flow.
The only thing, I've never really had a lot of experience with putting positive displacement pumps in parallel. The only time you really want to do that with positive displacement pumps in parallel would be is if you had very large hydraulic pumping system, not so much for pumping water. My concern there would be is pressure control on it, because positive displacement pumps can generate a lot of pressure real fast, where centrifugal pumps won't.
All right. Wade, if budget and money are not an issue, do you recommend to simply repair or replace a pump when failure has occurred?
Wade: That's another one of those wide open questions. It depends. A lot of your smaller, fractional horsepower pumps, manufacturers typically walk away from putting parts on the shelf. So let's say, for instance, I've got an inch-and-a-half Bell & Gossett circulating pump. And, you know, Joe and Jim are taking the thing out of service, and they were pulling it out of the plumbing to do some work on it. They just happened to drop a portion of it, and break the volute on the pump. What's surprising is the cost of replacing that pump is less than the cost of replacing the part. Like I say, a lot of the small, fractional horsepower pumps that are out there in the market, they kind of frown away from doing that. The pump that I use in the Trainco training course is a little and such a centrifugal belt drive. That pump probably has an acquisition cost of about $78, and the bearings and the shaft of that pump are $150. So there comes a time and a place. Now, when you get into the rather larger pumps, you know, you're talking pumps that are $300,000, $400,000, $500,000, or $3,000, $4,000, $5,000, the same thing, you have to determine what needs to be repaired on.
Okay. Wade, we have one more question, and this person wants to know if you/TPC Trainco can do training on D26, also known as decontamination pumps. Do you have any thoughts on that?
Wade: Decontamination pumps are one of those trick bags. I'd have to do a little research on that one. I would have to look into that before I could answer that question. I guess it would be depending on if their application and if they're certified is there some kind of rules and regulations that control the application and operation, those kind of scenarios. That would be something that I would have to research. But if it is a pump, and it's not physically dangerous in the position where it's sitting at, I'd say, "Yeah. We could look at that."
All right. Okay, well, that does it. Wade, thank you very much. Everyone on the call, thank you very much. If you have any further questions, just give us a shout, and we'll be happy to help you out in any way we can. Thank you so much for attending.