Cleaning and maintenance is one of those necessary evils: It takes time away from the project, but skipping it can be even more time-consuming and costly. Shotcrete pumps are no exception. Consider these tips for cleaning and maintaining high- and low-pressure pumps used to spray refractory shotcrete linings.
High-Pressure Hydraulic Swing Tube Piston Pumps
It’s essential that hydraulic swing tube pumps are kept in working order at all times. These pumps, commonly used for pumping mixes extreme distances, generate more than 2,000 psi of line pressure for working in the most demanding refractory applications.
Keep the hydraulic pumping pressure as low as possible to prevent premature wear, and conduct routine preventive maintenance on primary wear parts. Cup seals (Fig. 1), or piston cups, attach to the end of the hydraulic rams and are the most common wear parts on swing tube piston pumps. Regularly check poly packs, the wear plate and wear ring.
Clean the pumping system properly after each use to avoid premature wear on the cup seals and material pumping tubes. A swing-out or hydraulic-lift hopper (Fig. 2) offers easy and quick access for cleaning and maintenance.
Generously grease the outgoing housing, swing tube shaft and swing tube cylinders each hour during operation. Consider automatic lubrication systems (Fig. 3) for swing tube pumps. These drastically reduce maintenance costs and increase return on investment.
Low-Pressure Peristaltic (Squeeze) Pumps
Hydraulic peristaltic pumps used for shotcrete applications generate in excess of 450 psi of line pressure and do not pump material extremely long distances. However, they have a niche when pumping materials within 250 feet horizontally and 50 feet vertically.
Peristaltic pumps are extremely simple and safe to operate. These units run in reverse to remove blockages or obstructions without damaging the pump. They also can be operated as a skid steer work tool or by other equipment equipped with auxiliary hydraulics.
There’s only one wear part on these squeeze pumps: the rubber pumping tube, which makes them the most economical concrete pump. Maintenance costs are typically less than $1 per cubic yard of pumped material. To ensure maximum longevity of the pumping tube and reduce maintenance costs, keep a log of the amount of material pumped through each pumping tube. After noticeable wear, remove the tube, flip it 180 degrees and install it back in the pump.
Operators can easily clean peristaltic pumps with a round sponge ball since no concrete comes in contact with the pump’s moving parts. The concrete is simply pumped out of the hopper and the sponge ball is sucked into the pump’s inlet pipe. Next, flood the hopper with clean water. The sponge serves as a dam between the concrete being pumped and the cleanup water. Engage the pump in forward and the water pushes the ball through the pump and delivery system for a quick and simple cleanup.
Both high-pressure and low-pressure shotcrete pumps have advantages and disadvantages. Work with an experienced pump manufacturer to help determine the best pump for the desired application. This ensures minimal maintenance and downtime.
Tripp Farrell is president of Blastcrete Equipment Company. He can be reached at firstname.lastname@example.org or 800-235-4867.