waterbed

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A waterbed or water mattress is a bed or mattress filled with water.

Construction

Softside Waterbed 160 × 200 cm with dual heating

Waterbeds primarily consist of two types, hard-sided beds and soft-sided beds.

A hard-sided waterbed consists of a water-containing mattress inside a rectangular frame of wood resting on a plywood deck that sits on a platform.

A soft-sided waterbed consists of a water-containing mattress inside of a rectangular frame of sturdy foam, zippered inside of a fabric casing, which sits on a platform. The effect is to look like a conventional bed and is designed to fit into existing bedroom furniture. The platform usually looks like a conventional foundation or box spring, and sits atop a much-stronger-than-normal metal frame.

Early waterbed mattresses and many inexpensive modern mattresses have only one water chamber. These mattresses are commonly described in the industry as "free flow" mattresses. When the water mass was disturbed, significant wave action could be felt. They needed some time to stabilize after a disturbance. Later types employed wave-reducing methods, including fiber batting and interconnected water chambers. More expensive "waveless" modern waterbeds have a mixture of air and water chambers, usually interconnected.

Softside Waterbed 160 × 200 cm with two waterchambers and flexible chamberisolation inside

Water beds are normally heated. Temperature is controlled via a thermostat and set to personal preference, but is most commonly average skin temperature, 30°C or about 86°F. A typical heating pad consumes 150–400 watts of power. Depending on insulation, bedding, temperature, use, and other factors, electricity usage may vary significantly.

Waterbeds are usually constructed from soft polyvinyl chloride or similar material. They can be repaired with nearly any vinyl repair kit.

History

A form of waterbed was invented in the early 1800s by the Scottish physician Neil Arnott. Dr Arnott's Hydrostatic Bed was devised to prevent bedsores in invalids, and comprised a bath of water with a covering of rubber-impregnated canvas, on which lighter bedding was placed. Arnott did not patent it, permitting anyone to construct a bed to this design.^[1][2]

The use of a waterbed for the ailing Mrs Hale is mentioned in Elizabeth Gaskell's 1855 novel North and South.^[3]

In 1871 a waterbed was in use in Elmira, NY for "invalids". It was briefly mentioned by Mark Twain in his article "A New Beecher Church" which was published in The New York Times on 23 July 1871. There Twain said that: "In the infirmary will be kept one or two water-beds (for invalids whose pains will not allow them to be on a less yielding substance) and half a dozen reclining invalid-chairs on wheels. The water-beds and invalid-chairs at present belonging to the church are always in demand, and never out of service". This article does not contain enough information to determine the form of the beds involved.

Dr. William Hooper of Portsmouth, England, patented a waterbed in 1883. He devised it to relieve bed sore pains in his patients. Unable to contain the water and control its temperature, his invention was a market failure.

The modern waterbed was created by Charles Hall in 1968, while he was a design student at San Francisco State University in California. Fellow SFSU students Paul Heckel and Evan Fawkes also contributed to the concept. Hall originally wanted to make an innovative chair. His first prototype was a vinyl bag with 300 pounds (136 kg) of cornstarch, but the result was uncomfortable. He next attempted to fill it with Jell-O, but this too was a failure.^{[citation needed]} Ultimately, he abandoned working on a chair, and settled on perfecting a bed. However, because a waterbed is described in the novels Beyond This Horizon (1942), Double Star (1956), and Stranger in a Strange Land (1961) by Robert A. Heinlein, Hall was unable to obtain a patent on his creation. In 1980 Heinlein recalled in Expanded Universe that:

"I designed the waterbed during years as a bed patient in the middle thirties; a pump to control water level, side supports to permit one to float rather than simply lying on a not very soft water filled mattress. Thermostatic control of temperature, safety interfaces to avoid all possibility of electric shock, waterproof box to make a leak no more important than a leaky hot water bottle rather than a domestic disaster, calculation of floor loads (important!), internal rubber mattress and lighting, reading, and eating arrangements—an attempt to design the perfect hospital bed by one who had spent too damn much time in hospital beds."

However, Heinlein made no attempt to build his invention.

Advantages and disadvantages

Waterbeds have several advantages over traditional beds:

• The bed shapes exactly to the body, thus minimizing pressure, especially around the joints. Waterbeds remove pressure from the spine allowing the spinal muscles to fully relax, aiding in the treatment of backache.^{[citation needed]} In paralytic or movement-impaired people they can reduce the risk of bedsores.
• It is impossible for dirt and dead skin particles to penetrate the water mattress, which can then be wiped periodically with a cloth and vinyl cleaner. The cover over the mattress can be regularly washed—thus virtually eliminating house dust mites in the bed. Dust mites can trigger asthma, eczema, and allergies in people sensitive to them.

But there are also disadvantages:

• Heating a waterbed is costly. A waterbed consumes between 500 and 2000 kWh/year, depending on the climate, bed size, and other factors. Thus, a waterbed can easily consume more power than a refrigerator. The energy usage can be decreased by about 60% with the use of a foam mattress pad, if the water is not to be heated to body temperature.^[4]
• Since some hard-sided waterbeds are of different sizes than other mattresses, bed sheets are harder to find and come in fewer varieties. Soft-sided mattresses are conventionally sized to avoid this problem.
• Moving a waterbed is a more difficult process than moving a normal bed; the water must be drained and the frame disassembled, then the frame must be reassembled, the mattress refilled with water, and the water heated for a period of hours or days to get the new water to the correct temperature.
• Occasionally, water mattresses may leak. Plastic liners will reduce damage, but emptying, patching, refilling, and reheating it (and sleeping elsewhere until all this is completed) is certainly an inconvenience.
• As an alternative, airbeds may be considered as they too are flexible, offer all the advantages of a water bed and are considerably lighter in weight. They are much more flexible because air is compressible unlike water.
• The weight of a waterbed (a bed of 160 x 200 x 020 cm will weigh 640 kg or 1,410 lbs), will put a strain on many floorboards. But because the waterbed is 35-42 sq. ft. in size, the floor load stress is 40 lbs./sq. ft. or less, and the load is of no more concern than a refrigerator or filled bathtub.^{[citation needed]} Many modern codes require a minimum floor load of 150 lbs./sq. ft.
• Some apartment leases restrict the use of "water-filled furniture." This is because of concerns of water damage to the dwelling due to accidental leakage, not the stress on the floor.

References

External links

• U.S. Patent 3,585,356 -- "Liquid support for human bodies"
• British Water Bed Association
• Bad Fads Museum