Wednesday, 1 February 2012

Woodburning Stoves: A History


Wood burning stoves started out as a way to heat a home more effectively than with open fireplaces, which had traditionally been used. The first models were placed against the opening of the fireplace so that the fumes could escape through the chimney. They were essentially a metal box, but they heated a room more thoroughly than a traditional fireplace because they reached further into the room.
Eventually, wood burning stoves were developed that were completely closed. This meant that instead of relying on an open fireplace they had their own chimneys and a flue. This development allowed the stoves to be positioned away from the wall so that the heat was distributed all around the room.
Early Designs
Woodburner stoves originated in America and it was in 1642 that the first one was invented in Massachusetts. It wasn’t until 1744 that the idea was substantially improved when Benjamin Franklin produced his own wood burning stove. Named ‘the Franklin Stove’ after its inventor, it was made from cast iron. Although it was open fronted and similar in appearance to a brick fireplace, it gave off more heat than a traditional fireplace and less smoke whilst using a smaller amount of fuel.
Another improvement that Franklin installed was a flue, which was initially situated in the floor of the stove and later next to the chimney. The main feature of the Franklin Stove was the ability for air to circulate.
Various minor improvements then took place over the following two centuries, but the original design of the Franklin Stove is still credited to Franklin. This design remains today, but various changes to style and efficiency have taken place.
In 1796, the Rumford fireplace was constructed by Count Rumford. It developed from the original Franklin design but included various enhancements. One of these was to angle the hearth and make the choke of the chimney tighter so that the smoke would be drawn up the chimney faster.
Construction
Early wood burning stoves, on which modern designs are based, were made from either steel, cast iron or another type of durable metal. They had a thick door and adjustable grates to control the amount of air in circulation and therefore control burning.
Woodburners have a chimney at the top and a flue. They usually stand on brick, concrete or stone, and it is essential that the floor that they are mounted on is level. Smoke is drawn outside the building and will flow upwards providing the air outside is colder than the gasses inside the chimney.
Progress
As developments in wood burning stoves took place, they were able to perform other functions besides heating the home. From the early 20th Century features such as metal draws and ovens were added so that they could be used for cooking. They also changed in appearance, from a metal fireplace to a freestanding stove with four legs. These freestanding models were often constructed from cheaper materials, which were less resilient but had the advantage of making them portable. They had flat metal surfaces so that pans could be placed on top of them for cooking. Alternatively, a pot could be inserted into a hole in the stove and heated directly by the flames.
Late 20th Century Developments
The concept of a sealed unit with controlled air circulation remained, with the main changes affecting appearance and function rather than efficiency. For example, as well as being used for cooking, pot‐bellied and cylinder variations of wood burning stoves emerged. In the 1970’s, however, major innovations took place, which arose because of the oil crisis. As wood burning stoves increased in popularity their inadequacies became apparent. For instance, the use of a wood burning stove as the main source of heating for the home demanded enormous amounts of wood. Apart from this factor, they created pollution and were a fire hazard.
The fire hazard was a consequence of householders reducing the air intake of the wood burner once the fire was burning well. This was so that the stove would burn for longer periods and produce a more even heat distribution. The problem with this was that there would be unburned resins escaping up the flue. Once these resins cooled sufficiently creosote would form inside the stove pipe. This was hazardous as the creosote would ignite once a certain temperature was reached, resulting in a dangerously hot fire throughout the stove pipe.
This culminated in a drive towards producing more efficient models, which had longer burn times and lower levels of pollution.
 
The Present Day
Thankfully, today’s wood burning stoves have addressed earlier problems. Modern wood burning stoves are constructed from steel and aluminium and are airtight. They have firebrick linings which mean that they retain more heat and are therefore more efficient. They are also kinder to the environment as current models give off fewer gases, and any co2 that is emitted is absorbed by growing trees.
Nowadays, stoves have to meet set guidelines regarding smoke emissions due to environmental concerns, particularly with a number of urban areas forming smoke control zones, meaning you will need a stove approved by DEFRA to burn wood. Because they are considered as an environmentally friendly source of heating they continue to retain their popularity in the 21st Century. There are now a wide range of wood burners and multifuel stoves on the market in various shapes and sizes and with different heating capacities to suit requirements. What these modern wood burning stoves have in common is their efficiency and kindness to the environment. Added to that, many people find them attractive because they create a homely feel and a sense of nostalgia.

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