Industrial Design: Design the Dyson Way

Patrick G. Mahoney
Contributing Editor

James Dyson’s so-called overnight sensation, the Dual Cyclone vacuum cleaner, was anything but. In his book, Against the Odds, the British designer, whose bagless machine turned an industry on its ear, details a grueling, yearslong battle to prove his revolutionary design and bring it to market.

The interesting thing: Dyson never trained as an engineer. His background is in industrial design and styling.

In 1979, Dyson began work on a radical design for a vacuum cleaner in the stables behind his house. Up to then, his stint as an inventor was limited to the development of a new kind of wheelbarrow (the Ballbarrow), a high-speed landing craft (the Sea Truck), and as he puts it, “a couple of castles in the air.” For the next 12 years, despite increasing debt, he tried unsuccessfully to interest manufacturers on both sides of the Atlantic in what he called his cyclonic vacuum cleaner.

As a last resort, he began production on his own in 1992. Ten years later, after hundreds of prototypes, thousands of modifications, and millions of tests, one in four British households owned a Dyson. The company was selling a million vacuum cleaners a year in 24 countries and turning over $300 million annually. Total worldwide sales exceeded $10 billion.

Dyson’s training in industrial design is apparent in his vacuum cleaner. He claims it works better and, of equal importance to him, looks better than any of his competitors’ machines. The former art student hardly seemed the sort to topple industrial giants like Hoover and Electrolux. Still, Dyson’s design kicked the venerable bag-type machine to the curb, replacing it with a cyclone that spins at the speed of sound, in a chamber that can’t clog.

The Dyson vacuum’s outer cyclone rotates at 200 mph, removing debris and most of the dust while an inner cyclone rotating at 924 mph drives fine dust and even particles of cigarette smoke out of the air. Produced in pastel pink, the Dual Cyclone was a smash in Japan, winning the 1991 International Design Fair prize in Tokyo.

Where’s the suck?
At home, Dyson had an old reconditioned Hoover Junior, an upright model. For years, the machine annoyed him because it never had “much suck,” as Dyson puts it. It just seemed to push dirt and dust around the house. And emptying the bag didn’t result in a noticeable improvement. He realized the pores of the bag, which were meant to let out only air, were clogging with dust and cutting off the suction. “We were all victims of a gigantic con by the manufacturers,” he says.

As it happened, Dyson was also having suction problems at the factory which made his Ballbarrow, a wheelbarrow he invented that uses a ball instead of a wheel. There, overspray of an epoxy powder was collected on an 8 8-ft cloth screen in front of a gigantic fan with a three-phase motor — a sort-of giant vacuum cleaner. Production had to stop every hour to brush out the screen and gather the powder for reuse. Otherwise, the screen would clog and powder would fly all over the factory.

The spray-equipment maker said large industrial users collected airborne debris in a cyclone. The cyclone, it turned out, was a 30-ft-high cone that spun dust out of the air using centrifugal force — the kind of thing you might see on top of a saw mill.

Under cover of darkness, Dyson went to a nearby sawmill, climbed the fence, and “surveyed at close hand the gigantic symbol of my future.” He made some sketches and climbed all over it to learn how it worked, what its proportions were, and what it was made of.

The next day, Dyson and his workers welded a 30-ft cyclone together from sheets of steel and attached it to the roof. He “gleefully” tore the cloth screen from the opening of the duct and started the conveyor. The overspray “went straight into the gaping hole, up the [duct work] and around the walls at the top of the cyclone, spiraling down through the inverted cone to be collected by a bag at the bottom, while the air escaped into the sky. Production went on and on, with no stoppages until the end of the day,” says Dyson.

The similarity between ripping off the cloth filter and tossing out a vacuum-cleaner bag was obvious. It also occurred to him there was “no reason why it shouldn’t work in miniature, using a cyclone about the size of, say, a Perrier bottle.” That night, Dysonmodeled a foot-long version of the cyclone out of cardboard and duct tape. He covered the large end, leaving a hole in the top for the escaping air. Then, he attached a short length of hose to the discharge hole of the machine (where the bag had been) and connected it to the top of the cyclone, which was fixed to the shaft of the cleaner. The world’s only bagless vacuum cleaner worked flawlessly.

In the eye of the storm
A vacuum cleaner develops suction by means of a fan that discharges a powerful stream of air through the back or, in the case of the Dual Cyclone, through the front, above the suction head. The fan has blades set at an angle and when they rotate, they create airflow in an axial direction. Incoming air is filtered so air leaves and dust remains behind. Without filtration, either dust goes back into the room or air is trapped and the vacuum cleaner blows up.

Dyson’s prototype drew air up the pipe into the top of a cylinder, which tapered into a cone shape. His cardboard version was about a foot deep and 6 in. in diameter. Dirty air enters the cylinder at a tangent. As the particles make their first turn around the curved wall, their speed is multiplied by a factor of three. The cyclone is cone shaped so the reduced diameter accelerates objects again by about 50%. In this way, the cyclone accelerates dust particles from 200 to 600 mph and then 924 mph, faster than the speed of sound, or about 324,000 rpm.

The cyclone eve n forces cigarette-smoke particles to the bottom of the cone where they settle in a drum. At the top of the cyclone, in the middle, is a chimney where pure, odor free air escapes.

Of course, Dyson still needed to answer a host of questions before perfecting the vacuum’s design: For example, is a circular entry the best way to get the air in? What size should the entry be? Should it protrude inwards slightly? Should it come in at a pure tangent, or a half tangent? Should it contract as it enters? Should it be angled down to follow the natural downward spiral of the cyclone? How many entries should there be? And those are just questions about the entry point.

In the absence of formula, Dyson took Edison’s approach: test, test, and test some more. In the early years, he made hundreds of cyclones, then thousands. He found the important thing is the entry point. It should be oriented enter peripherally, and at a pure tangent. He even made one prototype with 140 entries, just in case it was better. But always there was just one flow of air. Questions about position, size and shape of the exit point, and every part of the machine had to be answered by testing.

The board of Kirk-Dyson, the company that manufactured Ballbarrow, was hostile to the cyclonic concept. So Dyson set out to “make the damn thing myself ” in a drafty coach house with no water, heating, phone, gas, or electricity. He built 5,127 prototypes before his Dual Cyclone went into production. For three years, he worked alone, “crawl[ing] into the house every night covered in dust after a long day in the coach house, exhausted and depressed because that day’s cyclone had not worked. . . In view of the fact that I was making only one change at a time, and working alone, I think that [building] a decent working prototype in four years was actually quite speedy work.”