When you have a dewatering job or a heavy slurry transfer, the first question is often: “Can I just use a standard trash pump sitting on the bank?”
The answer depends on physics. If your fluid is deep, thick, or full of solids, a standard surface pump is going to struggle—or fail completely.
Here is why moving the pump into the fluid (submersible) is often the only reliable solution.
1. The Physics: Pushing vs. Pulling
The biggest limitation of a standard surface pump (a pump sitting on dry land) is Suction Lift.
- The Problem: On Earth, atmospheric pressure limits how high a pump can “suck” water up a hose. Even the best pumps in the world max out at about 25 to 28 feet of vertical lift. Beyond that, physics simply won’t allow the water to climb the hose.
- The Solution: A submersible pump ignores this rule. By placing the pump head at the bottom of the hole, you aren’t pulling the fluid up; you are pushing it up. This allows you to pump from depths far greater than 28 feet.
2. Zero Priming Required
Standard pumps need to be “primed” (filled with water) before they can start working. If they lose prime—due to an air leak or a drop in water level—they stop pumping and can burn out their seals.
A submersible pump is, by definition, always primed. Because the intake is underwater, it can run immediately without setup time, and it won’t lose prime if the fluid level fluctuates.
3. Moving Solids and Sludge
Thick fluids (like drilling mud, sewage, or mining slurry) are heavy. Trying to suck them up a hose is like trying to drink a thick milkshake through a long straw—it takes massive energy and often fails.
A submersible pump applies force directly to the heavy fluid, driving it up the discharge line efficiently. This allows Fast Flow pumps to handle high-viscosity abrasive solids that would clog or destroy a standard suction pump.
The Fast Flow Advantage: Why Hydraulic?
Not all submersible pumps are created equal. Most on the market are Electric Submersibles, but at Fast Flow Pumps, we specialize in Hydraulic Submersibles.
Here is why that matters for your job site:
- Safety (No Electricity in the Water): Electric pumps require high-voltage cables running directly into the fluid. If a seal fails, it can be a major safety hazard. Our pumps are driven by hydraulic oil—removing the risk of electric shock in the water.
- Variable Speed Control: With a hydraulic drive, you can easily adjust the flow rate by changing the engine RPM on the power unit. Electric pumps are usually “on or off.”
- Incredible Power-to-Weight Ratio: Because we don’t need a heavy electric motor inside the pump casing, Fast Flow pumps are significantly lighter and more compact than electric equivalents of the same power.
- Run Dry Capability: Many electric submersibles will overheat and burn out if they aren’t fully submerged in cooling water. Fast Flow hydraulic pumps are cooled by the hydraulic oil, meaning they can “run dry” without damaging the internal components.
Conclusion
If you are pumping shallow, clean water, a standard trash pump is fine. But if you are dealing with deep lifts, heavy sludge, or hazardous environments, you need a submersible.