Central Vacuum
Ducted Vacuum Systems are also called Central Vacuums and Built-In Vacuums.
Cyclonic Action
Cyclonic action describes the natural action found in a tornado. In a ducted vacuum with cyclonic filtration, the air carrying the dust and debris moves through a tornado action. The air swirls downward in a cone-shaped pattern. At the bottom of the cone, it starts swirling upward again, inside the downward cone. Thus this is sometimes called a 'reverse' tornado action or 'dual cyclonic action'. The vast majority of the debris separates from the air steam as air reaches the bottom of the swirl, and is deposited in the dirt container. Only a small fraction remains in the air, to be removed by the secondary, cartridge-type filter or other filter type.
Decibels
While decibels are a measurement of a sound volume, the average human ear can perceive a significant difference in volume between 5 decibels. The lower the decibels level, the quieter the unit.
Fan
The fan is the combination of blades that spin around to create the airflow to produce the vacuuming action. A ducted vacuum motor with two fans is called a 'two-stage' motor; if it has three fans it's 'three-stage' motor.
Flow Through discharge
In some less-expensive motors, the air drawn from the home flows right through the motor to cool it. Unfortunately this air is laden with the dust from the home which dirties and contaminates the motor. This air is also warmed by friction as it moves through hoses and piping, and is substantially warmer so it is less able to cool the motor. Thru-flow motors will overheat if they are run for long periods of time without adequate air flowing through the system.
l/s(litres per second)
A common unit of the measure of air moved by the vacuum fans. This measures the "volume" of air the motor is capable of moving and works in tandem with "Suction". Airflow can be a bit confusing however, since performance measurements are taken from the motor and do not factor any resistance found in a typical ducted vacuum system. Filtration, piping, hoses and accessories all restrict and reduce the amount of actual Airflow a system has. While Airflow is important to system performance, Suction or the "pulling of air" maintains the Airflow velocity necessary to sweep dirt and debris away at the hose end where vacuuming takes place.
Motor Brushes
The sliding contacts that provide electrical power between the stationary stator and the rotating armature of an electrical motor. Brushes are the most wearable part of an electric central vacuum motor, and should be replaced every few hundred hours or few years of operation.
Motor Speed
Measured in revolutions per minute (RPM).
Paper Filter Bag
A collection device for dust and debris.
PVC (Poly Vinyl Chloride)
A common plastic polymer that provides excellent appearance and longevity with good flame retardence at an attainable price. All of MD Manufacturing central vacuum fittings are made from virgin PVC.
Stage
This indicates the number of sets of fan blades in a central vacuum motor. Each fan - set of blades - increases the vacuum, or speed at which air is drawn through the system. The first fan starts air movement; the second increases it, and if there is a third fan it increases airflow still more.
Tangential by pass
Tangential bypass refers to the vacuum motor’s actual design. The design uses a separate fan for cooling the motors armature and stator (motors winding), the armature spins and the stator is stationary. Tangential bypass uses a series of impellers (fans) and shrouds to pull airflow through the motor and a special exhaust duct (called an exhaust horn) to port the exhaust out of the motor. The entire fan/shroud/horn assembly is separate from but connected to the motor. This design is widely accepted as the superior system for it's efficiency and reliability. Tangential bypass motors are often used in one of two sizes for central vacuums, 145mm or 183mm diameter and may have a series of one, two or three impeller (fan) blades referred to as motor stages. Bypass vacuum motors often have a lifespan of 25 plus years with little maintenance.
Volts
A measure of the electrical potential employed by a central vacuum motor. Typically, motors require common household current of 240 volts in Australia. Voltage is to electricity as pressure is to water; a measure of potential or driving force.
Vacuum
A total vacuum is the absence of everything, even air. Vacuum cleaners actually create a partial vacuum, or more accurately, an area of reduced air pressure, as air moves outward within the fan. Airflow is created as air with normal air pressure moves toward the area with the reduced air pressure.
Waterlift
This measures the suction strength of a ducted vacuum motor. Essentially, it tells how much "pull" or "lift" power the motor has. This measurement is always taken at its maximum value, the 0" inch orifice (sealed vacuum) where suction is at it's greatest. Since this measurement is taken from the 0" orifice, it is very misleading. This measurement does not take into account piping, hoses or accessories etc., thus giving a false measurement of power. Often referred to as Inches or Waterlift or Vacuum, Suction is vital to overall system performance since it is the "pull power" that maintains Airflow though the complex network of vacuum pipe, hose and accessories. While Airflow is necessary for a vacuum cleaner to work, suction creates the lift and velocity of air which sweeps dirt away. Waterlift is NOT a true measure of suction, however it is a form of measurement and part of the equation when measuring Air Watts. This is the most misleading measurement of suction power.
