Hydraulic or Mechanical Drive

Choosing Hydraulic vs Mechanical Drive Systems

A hydroseeding machine has two primary functions:  A mixing paddle system in the tank to mix the slurry of water, mulch, seed, and other ingredients and a pump for pumping the mulch slurry out of the tank for application onto the ground. Powering those functions is simply a matter of turning the shaft of the mixing paddles and turning the shaft and the pump with adequate torque and speed.

Mixing in the Tank

Loading and mixing a machine quickly is important for job-site efficiency.  Mechanical drive systems typically provide massive power for mixing paddles to mix the slurry almost instantly.  Some hydraulic systems do not deliver adequate power for instant mixing.  That lack of power is addressed with a reversing function.  Reversing the paddle blade direction will help achieve adequate mixing.  However, reversing the agitator to obtain adequate mixing wastes time resulting in slightly more labor costs each tank load.  A hydraulic system for the agitator should be designed to provide enough power for instant mixing and include reversing.

Pumping from the Tank

The most important pumping function for hose applications is the ability to pump thick slurries through long hoses. The most important pumping function for tower applications is to shoot any slurry, thick or thin sufficient distances. Whether or not the pump is driven with a mechanical system or a hydraulic system is of no importance if the pump is turned with adequate power and speed.

Points of Comparison

Any system, including hydraulics, is subject to good or poor design.  Any system will wear out.  Any system has it’s strong points and weak points.  Below are a few of these points.

  1. Hydraulic systems eliminate the need for clutches, belts, or chains.  Any of these components can be a failure point. However, hydraulic systems have hoses and other components that fail.  Hydraulic failures will most likely require special order parts resulting in more time down time to make repairs.
  1. Hydraulic systems can be designed to easily reverse the direction of the agitator or pump.  

Reversing the agitator is valuable if the agitation system is weak.  Reversing the agitator is also useful to deal with a common operator error of getting too much water in the tank before all the mulch is loaded.  This occurs when water is allowed to fill the tank too quickly.  Reversing the agitator will take the mulch floating on top down into the mixing paddles and into solution.

Reversing a gear pump is very useful.  If a clog occurs somewhere in the system, reversing a gear pump will most likely clear the clog.  A centrifugal pump does not work run in reverse.

  1.  Hydraulic systems typically require 15%-20% more horsepower to deliver the same amount of power to the agitator and pump. TurfMaker® mechanical machines with lower horsepower engines are less expensive than hydraulic machines and usually outperform competitors hydraulic powered machines

SUMMARY – Hydraulic Power Systems versus Mechanical Power Mechanisms:

  1.  For the actual performance of the machine, it simply doesn’t matter.
  2.  Reversing systems with hydraulics provide better recovery from operator error.
  3.  Reversing systems with hydraulics provide conveniences and user friendliness.
  4.  Praise or criticism of one system versus the other is usually related to good or poor design.
  5.  Annual maintenance costs are not significantly different.
  6.  Hydraulic systems require 15%-20% more horsepower.
  7.  Hydraulic systems costs more, plus the costs of a larger engine.