http://www.cvcdirect.co.uk/explained.htmlBasically the suction motor is fixed (usually in utility room or garage) and ducting is installed around the house at the first fix (i.e. behind the plasterboard) and attached to the suction motor. At intervals around the house there are little nozzles the size of light switches. You insert your hose into the nozzle and it automatically switches on the vacuum motor and you vacuum in the same way. You can also have a nozzle at floor level in the kitchen so you just sweep kitchen mess to the hole in the skirting board, open the nozzle and it gets sucked away.
The collection cylinder has a capacity of about 5 litres.
This enables much more powerful vacuum engine, much greater intervals between emptyings and no having to drag the hoover around the house behind you. Only have to store the hose and attachments. There's even an attachment for animal grooming!!
When vacuum cleaners were first invented in Victorian times - this is how it used to work. House would be built with the ducting, a vacuum man would come with a portable motor, hook up to the ducting and then all the servants would frantically hoover away for a hour and the motor guy would move to the next house..... apparently