The airpath from floor to exhaust
Air in a vacuum cleaner travels one way. It enters at the floor tool or crevice nozzle, passes along a wand or hose, reaches a separator where heavy dirt drops out, crosses one or more filters, goes through the motor and fan, and leaves through an exhaust that may carry a final filter. Cordless sticks and robots fold this path into a compact body; canisters and wet dry drums stretch it out. The order matters. In most machines the filters sit before the motor so the fan stays clean, which is called a clean-air or dirty-air motor design depending on whether the dust passes through the fan itself.
Every stage is a restriction. A narrow wand, a clogged filter or a full bag all raise the resistance the fan must work against, so the pressure difference rises and the airflow falls. This is why a machine that tests well at a laboratory with an empty bin can feel weaker after ten minutes of real cleaning, and why bin design and filter choice matter as much as motor power.
Motor and fan: where suction is made
The motor spins one or more fan stages, each a pair of an impeller and a stationary diffuser. The impeller flings air outward, the diffuser slows it and converts speed into pressure, and more stages add more pressure. Two motor families dominate. Corded machines mostly use a brushed universal motor, simple and tolerant of price pressure, with carbon brushes that wear. Cordless and robot machines use brushless DC motors, typically in the range of 90,000-120,000 rpm, driven by a small controller. Brushless motors are more efficient, run quieter at a given airflow and last longer, but the controller adds cost. The vacuum motor page lists the options a plant will ask about, and the suction and airflow guide explains how the pressure and flow figures relate.
| Stage | Job | What it does to the airflow |
|---|---|---|
| Nozzle and brush | Seal on the surface, agitate, gather dirt | Sets how much air passes through the carpet; a poor seal wastes pressure |
| Wand or hose | Carry air and dirt to the body | Narrow or long runs add friction losses |
| Separator | Drop heavy debris in a bag or cyclone | A full bag or clogged cyclone outlet raises resistance |
| Filters | Protect the motor, trap fine dust | Finer media captures more and restricts more |
| Motor and fan | Create pressure difference and flow | Fixes the maximum suction and airflow |
| Exhaust | Return cleaned air to the room | Final filter and sealing decide what leaves the machine |
Suction and airflow are different curves
A fan has a characteristic curve. With the inlet fully blocked it reaches its highest pressure and moves no air; with the inlet wide open it moves its highest volume and builds almost no pressure. Real cleaning happens in between, and the point on the curve depends on the nozzle, the floor and the state of the filters. Typical cordless sticks quote 15-30 kPa sealed suction, entry models 10-20 kPa, and handhelds 5-15 kPa; robots are usually quoted in pascals, commonly 2,000-6,000 Pa. These are category ranges taken from datasheets, and a quoted sealed-nozzle figure says nothing alone about carpet performance. Ask for the airflow at the nozzle and the test method, which is where IEC 62885 helps.
Dirt separation and filtration
Separation happens in two steps. First a bag or a cyclone removes the bulk. A bag collects dirt by letting air pass through porous paper or nonwoven; a cyclone spins the air so heavier particles move to the wall and fall into the bin. The fine fraction then meets the filters: a foam or mesh pre-filter, a pleated cartridge, and in many machines a HEPA-class stage. EN 1822 and ISO 29463 define HEPA grades H11 to H14 by capture at the most penetrating particle size; an H13 filter captures at least 99.95% there. Whether the machine as a whole keeps dust in depends on sealing as well, so gaskets and housing joints matter. For comparison of the two main separators see bagged vs bagless vacuums and what is a cyclonic vacuum, and the filtration grades guide covers grades in detail.
Why machines are loud, and what a plant can do
Noise has three sources: the motor and its bearings, the fan blades chopping air, and air turbulence in the path. Typical cordless sticks sit around 65-80 dB(A) according to datasheets, measured by a method such as IEC 60704-2-1, and the figure depends heavily on the power mode. Plants reduce noise with foam mounts for the motor, tuned inlet and exhaust paths, smoother air passages and balanced rotors. These changes cost money and sometimes airflow, so a quiet design is a trade-off, which the noise levels guide discusses. A noise figure without the measuring distance and power mode is not comparable between models.
Powering the motor
A corded machine feeds mains power through a cord and a switch. A cordless machine routes power from lithium cells, through a battery management system, to the motor controller; runtime is simply pack energy divided by average draw, so typical 21.6-25.2 V packs of 2,000-4,000 mAh give about 30-60 minutes in normal mode and far less on boost. A 12 V car unit draws about 60-150 W from the socket. These differences explain why the standards change with the power source, as set out on certifications guide.
Why the same motor can feel different
Two machines built around the same motor can clean very differently, because the airpath around it is different. A wide, smooth passage with a good floor seal delivers more of the motor's capacity to the carpet than a narrow, bent passage with a leaky joint. This is also why component swaps need re-testing: a larger filter or a new brush head changes the resistance, and the plant must confirm the result on the finished machine rather than assume it from the parts.
What to ask a plant about the airpath
- Ask for sealed suction and airflow at the nozzle, with the standard or method used.
- Ask what happens to airflow when the bin is full and when the filter is dirty.
- Ask for noise at a stated distance and mode.
- Ask which parts wear: carbon brushes, filters, belts, seals, batteries.
- Ask for the filter grade by EN 1822 name, not by marketing description.
Send the answers and the target market through the quote form; the desk will compare partner plants against the same checklist, with every quoted figure confirmed in writing.