OPERATING INFORMATION
| ValveSeats |
Downhillpumpingcanbedifficultonsomejobs.Itissuggestedthat a sponge 2”x 4”x 6” be placed in the hose before the start of pumping.Wetthespongebeforeplacingitinthehose.Reference the Operating Suggestions at the start of this section for slurry procedures.
The reason for using the wet sponge is to keep the slurry from running too far ahead of the concrete and so reducing the possibility of separation.When the pump is stopped, the material can flow slowly down, due to gravity, and cause the hose to collapse.
Whenpumpingisresumed,youcanexpectablockageatthepoint ofhosecollapse.Topreventthisfromhappening,thehosecanbe “kinked off” at the discharge end when the pump is stopped to prevent the gravity flow of the material in the hose.
The use of stiffer mixes when pumping
VerticalPumping
When pumping vertically up the side of a building, above 40 feet, we would recommend the installation of steel pipe securely fastened at intervals as necessary to support the pipe. Ninety degree,longradiuspipesweepsshouldbeinstalledatthetopand bottom of the steel line.
Usea25ft.hose,orshortsection,offthepump;andforthebalance of the horizontal distance to the vertical line, use steel pipe.This type of installation has been satisfactory on many jobs being pumpedinexcessof100feethigh.Linepressuresarealwaysless using steel pipe as compared to hose.
When pumping vertically using all hose, it is recommended not to go higher than 50 feet with hose.The hose should be tied off at intervals of 10 feet, if possible. Special attention should be given whentieingthehoseoffatthetopasthehosewillhaveatendency to stretch when filled with concrete.This will increase the possi- bility of a blockage at the point where the hose is tied off.To avoid this, a long radius of 90 degree elbow is recommended. The suggested place to tie off is on the hose, under the clamp.
If the volume at the end of hose starts to decrease gradually and eventuallyalmoststops,itisquitelikelythatthevalveseatshave had excessive wear and need replacement. Once they have reached a certain wear point, they may“channel out”rapidly and material will reciprocate past the ball on each stroke.
The hollow steel ball should be replaced when it starts to show dentsorappearstobebadlyworn.Sandandaggregatematerials insomeareasareextremelysharpandhardandthereforehighly abrasive.Undertheseconditionswhenpumpingstiffmixes,orto high elevations which cause line pressures, it will be noted that valve components may have short wear life.
If this condition exists, it is advisable to remove the manifold only, andinspectthelowerseatattheendofeachday.Ifitappearsthat the seat is beginning to“channel out", replace before starting the nextday’s pour.
The upper valve seat can be inspected after each washout by running your finger around lower edge of seat where the ball makescontact.Youcanreachthisfromtheinsideofthehopper.Be sure that the engine is turned off.
Pulsation
A slight pulsation of the hose will always be noticeable near the pump.Excessivepulsationofthehosenearthepumpisnormally due to higher than average line pressures caused by stiff, harsh mixes, or extremely long pumping distances.
The use of 2
If excessive pulsation exists in the hose, it is advisable to use burlaporsomemeansofwearprotectionunderthehoseatpoints wherethehosemaywearthroughtheoutercover;e.g.overforms, steel or sharp curbs.
Itisstronglyrecommendedthatsteel
NOTE pipe be used on ALL vertical pump- ing for safety and convenience.
PAGE 32 — MAYCO C30HDZ PUMP — OPERATION AND PARTS MANUAL — REV. #12 (04/03/12)