3. IT'S ALL ABOUT THE FLOW: Optimizing Yards per Hour

Want to maximize the performance of your concrete pump? Not getting the yards per hour the spec book says you should? Chances are your hose is the limiting factor. When it comes to concrete pump performance, it's all about the flow!

Several factors contribute to the yards per hour that your pump can produce, such as material cylinder diameter & length, piston face pressure, horse power...and most importantly...the amount of reduction the concrete experiences from the moment it enters your hopper till it exits your hose. Most pumpers will argue that the bigger the machine, the more yards per hour you can get...and that's true...if you use the appropriate hose. But, if you have a 50 yd/hr pump and you attach a 2” hose to it, you're only going to get about 25 yd/hr. If you have a 70 yd/hr pump and you attach a 2” hose to it, you're still only going to get about 25 yd/hr. The reason is reduction.

REDUCTION...

Reduction is the compression of the space through which concrete is forced. The more the space is compressed, the slower the concrete moves. Imagine a room full of people when a fire alarm sounds. People will rush quickly to the door, but once there, progress out of the room slows drastically as only a few can fit through the doorway at a time. Concrete reacts the same way. A 50 yd/hr pump will have 6” material cylinders capable of pushing a specific volume of concrete at a specific rate, but when you minimize the diameter of the space through which the concrete is forced (like attaching a 2” hose), you significantly limit the rate with which the concrete can flow.

The yards per hour specified for a concrete pump is calculated by counting the strokes per minute in relation to the capacity of the material cylinders. Most 50 yd/hr pumps have 6” material cylinders and a 5” outlet, which means that there is already a 1” reduction in the swing tube limiting the listed yards per hour of the pump. A 70 yd/hr pump will have a 2” reduction by the time the concrete reaches the outlet, further limiting the yards per hour.

To maximize the yards per hour your pump produces, you would need to use a hose the same diameter as your outlet. This isn't feasible in most situations as any hose above 3” is too heavy for most to handle once filled with concrete. By far, the most common size of hose used in small line concrete pumping is 2”. This size of hose is manageable when filled with concrete and easy enough to roll and stack when the job is done. So if you're someone who uses 2” hose, you have no reason to make a steep investment in a 50 yd/hr concrete pump.

MITIGATION...

So are there ways of mitigating reduction? Not really, but from a physics standpoint, the longer the distance across which you stretch the reduction, the smoother your machine will pump. For instance, if you are attaching a 2” hose to a 4” or 5” outlet...the longer the reducer you use, the better. Forcing reduction across a short distance puts strain on the engine and creates dangerous back pressure that will cause your hose to kick. There are all sorts of reducers and elbows available to attach your hose to your pump, but understanding how these work together is important for safe and efficient pumping. It's also important to use a quality hose primer. Preparing your hose with a product like SMOOTH MOVE will reduce viscosity and help prevent your mix from separating and creating a clog.

REDUCING COSTS...

A General Purpose concrete pumper (someone who specializes in slabs, footers, and blockfill) using a 2” line has no need for a pump spec'd any higher than about 35 yd/hr. The jump in price from a 35 yd/hr pump to a 50 yd/hr pump is around $40,000. With that savings you could buy a truck to pull your machine. Not mention the fact that a 35 yd/hr pump is physically smaller and doesn't require as large of a truck to tow it...so extra savings there as well!

If you're in the concrete pumping business, don't buy more pump than you can use. If you run 2” hose, don't throw away tens of thousands of dollars on a pump that has potential you will never reach. Tailor your pump to your need. If you use predominately 2" line and you want to simplify this process, perhaps you should check out the REINERT ZR-430. This pump was designed specifically for 2" linework. It has 4" material cylinders, a continuous 4" swingtube, and a 4" outlet...which means there is no internal reduction. If you have questions regarding which pump is right for you, please visit the link below!

Farran Equipment Company, Inc was established in 1984 and has since grown to be a leading equipment and service provider in the Concrete Pumping industry. Serving clients across the United States and overseas, Farran Equipment Company specializes in all things concrete from pumps and parts to hose, tools, and service. Located in North Charleston, South Carolina Farran Equipment Company is dedicated to quality service and customer satisfaction.