A Brief Look at the Past
Peristaltic pumps have been around for a long time. Simply put, peristaltic describes the action that moves material through a tube or hose. It’s the action that takes place in animal bowel systems, as well as what happens when you squeeze a tube of toothpaste.
Pumps that are called peristaltic have rollers that roll along a tube, squeezing the material toward and out the tube’s open end. In this arrangement, the hose keeps the material confined and prevents the machinery from coming in contact with whatever it’s moving.
Over the years, peristaltic pumps have been designed for many different uses. For example, all machines that move blood and other materials in a hospital are peristaltic.
Concrete is another material for which peristaltic pumps were developed. One of the earliest, successful ones used rollers that squeezed the hose to move the concrete towards its destination. The hose could handle being squeezed, but to get a refill from the hopper, it had to be run in a vacuum. Problem: the vacuum required all kinds of seals that necessitated continual maintenance.
So, for concrete, the piston pump took over. We didn’t see peristaltic concrete pumps for quite a number of years. But now they’re back and gaining in popularity.
The Peristaltic Hose
It’s the reason for this far better development. The newest peristaltic hoses are constructed of open-cell polyurethane, a material that has many applications, including polyurethane springs for shearers and tongs. One manufacturer claims, that before needing replacement, tongs with polyurethane springs will run five times longer than those with steel springs.
Open-cell polyurethane also makes it possible to build a concrete hose with side-walls that have a really serious memory. After enduring a healthy squeeze, this hose remembers how to jump back and resume its rounded shape. More importantly, as the hose jumps back, it creates a vacuum, sucks concrete from the hopper and refills itself.
Advantages and Disadvantages of the Peristaltic Hose
Contamination – usually is not a big problem since a little dirt will not contaminate concrete. Nevertheless, because of the way in which the peristaltic hose handles the material it’s transporting, the possibility of contamination is virtually nonexistent.
Wear – because the hose confines the concrete, there’s far less wear on the pump. The concrete simply doesn’t rub against pump parts but only against the sides of the hose. Result: When you attach a new hose, you essentially have a brand new pump.
Wear affects a power pump or piston pump much differently. Piston pumps rely on metal parts to act as closures that force the concrete out the end of the hose. From the first dab of concrete that rubs against those metal closures, they begin wearing. As wear continues, the pump degrades, and it takes serious money to replace the worn points. So, operators normally wait as long as they can and try to get the most concrete pumped before making repairs. When repairs are made, operators essentially have a new pump; but usually for a long time before repairs are made, they use a pump with leaks around its steel seals.
Operators of a peristaltic pump should stock spare hoses and should change them. Monolithic advises clients to budget three to four dollars a yard for hoses. That’s about the same as what’s required for steel seals on piston pumps. But a more frequent hose replacement consistently provides the operator with a newer, better functioning pump.
Peristaltic pumps generally will not push at the same high pressure as a piston pump. Consequently, a worker is far less likely to get hurt from a hose rupturing or a clamp letting go. But it also means that operators really need to know what they are doing, and they need to make sure their concrete mix is a good one – one that properly moves through the pumping system. Remember: the better the concrete mix, the better it pumps. Harsh, low cement-ratio mixes will not give you a superior end-result concrete, nor will they pump well. Such mixes need higher pressure pumps.
Here’s another fantastic advantage of the peristaltic pump: its delivery of the Shotcrete is much more even. Unlike the piston pump, the peristaltic pump does not bounce its nozzle operator all over the place. Consequently, material goes onto a surface with a smoother, steadier action, producing a much nicer job of Shotcreting.
Monolithic Pumps are all Peristaltic
They were designed specifically for spraying high quality Shotcrete, and they incorporate state-of-the-art technology. The hoses are manufactured for Monolithic by crafters who really know their business. The pump design is as simple as we can make it. Usually it can be serviced locally, it costs less, it’s far easier to troubleshoot, and it’s more likely to do the job you want it to do.
Even after a long period of storage, it usually only takes lubrication to get the Monolithic pump going again. In our newest designs, we have even eliminated the chain drive. Monolithic concrete pumps are now totally run with a direct line hydraulic system.
Monolithic pumps are as simple as we know how to make them. We have developed these pumps for our own use as well as that of our clients, and we maintain an ongoing improvement program that considers any and all suggestions that might make our product better.
Our Family of Pumps
Monolithic’s small pump, direct drive 1500s work especially well for builders of fences and small domes and were designed to be used primarily with Monolithic Concrete Mixers. The hopper for our 1500 holds 1 1/2 loads from the mixer. These pumps can also be used out of a Redi-Mix truck, but they only spray about 3 yards an hour. Most Redi-Mix companies won’t stand for that slow of a transfer. At a job site, Monolithic’s 1500s can also be effectively used with standard concrete mixers.
We often talk with folks who plan to use large pumps to build small domes with diameters of no more than 50 feet. But such projects usually require only 30 to 50 yards of concrete that can be most efficiently sprayed with the smaller 1500. It’s easier to handle and will spray about 3 yards an hour. Forty-eight yards of concrete divided by 3 yards per hour equals 16 hours of spraying. But all of that concrete cannot be applied in one day. It must be applied over several days so that the concrete has time to set. If you use 4 days to apply the concrete, you’re only applying a few yards per day. The 1500s can easily spray 8 to 10 yards of concrete in a day, so there really is no reason to use a larger pump.
Monolithic’s GHP 2000 is designed for larger projects and to be used primarily with a Monolithic Concrete Mixer whose hopper holds 2 bucket loads. Operated by skilled workers, the Monolithic Concrete Mixer can easily mix 4 to 5 yards of concrete per hour. Monolithic’s 2000 pumps will spray about 6 yards of concrete an hour. This is the pump for the builder working on a large project or a number of various projects.
Each of Monolithic’s pumps is designed on skids, rather than trailers, but they can be put on trailers. For many applications, a trailer-mounted pump works well. In building domes, our crews have found that they like hauling more than the pump in their pick-ups. They like using a trailer on which the pump, mixer, skid steer, scaffold and miscellaneous supplies are loaded. Monolithic makes trailers for each of its pumps, so getting a trailer to fit your needs should not be a problem. Monolithic also makes custom trailers.
We have found that on a job site, a concrete pump that sits on the ground vibrates less and is easier to operate and fill. Therefore, we prefer to have the concrete pump on the ground. The skid steer can easily pick up a 1500 or 2000 pump.
Obviously, Monolithic carries a full line of high quality equipment and supplies – everything and anything a dome builder needs. And we are here to help. We’re easy to reach by either phone or email so please feel free to contact us with your questions.
February 6, 2014