Dishwasher

[edit] Introduction

A dishwasher is an appliance that uses very hot water and specialist detergent to clean dishes, glassware, cutlery and other kitchen items. There are consumer and commercial machines available, which perform the same function, but with differences in capacity and temperature.

[edit] History

The earliest version of a mechanical dishwasher was patented in the United States in 1850. The inventor, Joel Houghton, referred to the device as a machine for cleaning crockery or other types of table furniture. This device included a cylinder with a rack to hold the items being washed. A hand crank made the rack move while water splashed onto the items as they rotated in the machine.

The next iteration was introduced in 1886 by Josephine Cochran (a wealthy socialite) and George Butters (a mechanic). The rack and water jet system they devised was also hand powered and was displayed to the public at the 1893 Chicago World’s Fair. The invention from the Garis-Cochran Company (later to become part of KitchenAid) garnered much attention, particularly from commercial organisations, and it was awarded the highest prize at the fair for "best mechanical construction, durability and adaptation to its line of work".

Patent serial No. 187,276 submitted by Cochran on 31 December 31 1885.

In 1924, William Howard Livens from the UK invented a non-electric dishwasher for consumer use. This machine incorporated many of the features found in modern machines, but was not widely adopted.

In 1929, Miele invented the first consumer dishwasher operated by an electric motor. However, it wasn’t until the 1950s that consumers began to see the benefits of this device, which had been thought of as a luxury up until that point. These devices were portable and independent, and some had to be manually hooked up to a sink when in use. Eventually, consumer kitchens adopted continuous countertops and uniform cabinets, so dishwashers could be integrated into the layout.

[edit] How dishwashers work

Most dishwashers operate by following the same basic steps:

• Water is added and heated. Most commercial machines use water heated to temperatures of 65–71°C while sanitation occurs at an 82°C "final rinse" temperature or through the use of a chemical sanitiser. Consumer dishwashers commonly use 75°C water, although some operate effectively with advanced detergents and lower temperatures (50–55°C). The temperatures are lower for consumer models to prevent the risk of accidental scalding.
• The detergent dispenser opens and water is sprayed at the items to be cleaned.
• Used water is drained.
• Items are rinsed with fresh water.
• Used water is drained.
• Air is heated to dry the items (commercial machines may use a different, faster method).

[edit] Related articles on Designing Buildings Wiki

• Appliances.
• Hot water.
• How to design a kitchen.
• Kitchen.
• Mechanical, electrical and plumbing MEP.
• Plumbing.
• Smart homes will be smarter than you think.
• Tap.