The Physics of Suction: Why Water Lift Matters More Than Airflow
When buying a vacuum motor, most people look for the biggest number. Usually, that’s CFM (Cubic Feet per Minute). But if you install a high-CFM, low-pressure motor in your central vacuum system, you will be disappointed. The Ametek 115334 excels not because of its air volume (102.7 CFM), but because of its massive static pressure: 110 inches of Water Lift. This is the physics of deep cleaning.
Water Lift vs. CFM: The Garden Hose Analogy
Imagine a garden hose.
* CFM is the water flowing out freely onto the grass. It moves loose leaves easily.
* Water Lift is what happens when you put your thumb over the nozzle. The flow drops, but the pressure shoots up, blasting away stuck mud.
In a central vacuum system, you are pulling air through 50+ feet of PVC piping and a restrictive hose. This resistance is like the thumb on the nozzle (Analogy). A high-CFM motor collapses under this resistance. The Ametek 115334, with its high Water Lift, “muscles” the air through the long pipes, maintaining suction even at the end of a 30-foot hose. This static pressure is what physically lifts heavy grit (sand, coins) from the base of a deep-pile carpet against gravity (Physics).
The 2-Stage Multiplier
How does it achieve 110 inches of lift? The secret lies in its 2-Stage Blower.
A single-stage motor has one fan. The 115334 has two fans mounted on the same shaft, working in series.
- Stage 1: Air enters the first impeller and is accelerated outward by centrifugal force, creating a pressure drop.
- Stage 2: This pressurized air is not exhausted; it is fed directly into the intake of the second impeller.
- Compounding: The second impeller accelerates the air again. According to fluid dynamics, this compounding effect doubles the pressure differential relative to a single-stage unit of the same speed (Thesis). It is essentially a “twin-turbo” setup for your vacuum.
Tangential Discharge: The Efficiency Path
Look at the shape of the 115334. It has a “horn” sticking out the side. This is Tangential Discharge.
Cheaper “Peripheral Discharge” motors vent air through slots all around the casing. This creates turbulence and backpressure as the air hits the motor housing.
In Tangential Discharge, the air exits the fan chamber in a straight, smooth line tangent to the rotation. This laminar flow reduces air friction and turbulence noise (Physics). It allows the motor to maintain its high velocity with less electrical energy, converting more of those 13 Amps into suction and less into waste heat and noise.
The Energy Equation: Air Watts
The industry tries to combine these factors into a single number: Air Watts.
\text{Air Watts} = \frac{\text{Vacuum (Inches of Water)} \times \text{Airflow (CFM)}}{8.5}
The 115334 delivers 384 Air Watts. This represents the actual hydraulic power of the airstream available to do work. While newer motors might claim higher peak Air Watts, the Ametek 115334 delivers this power across a wide, stable RPM band, ensuring consistent cleaning performance whether the bag is empty or full.
Conclusion: The Heavy Lifter
The Ametek 115334 is not a leaf blower; it is a hydraulic pump for air. Its engineering prioritizes torque (pressure) over speed (volume). For a central vacuum system fighting friction in 100 feet of pipe, this high-pressure, 2-stage architecture is the only physics-compliant solution.