Worth to know
A drain cleaner is a chemical-based consumer product that unblocks sewer pipes or helps to prevent the occurrence of clogged drains. The term may also refer to the individual who uses performs the activity with chemical drain cleaners or devices known as plumber's snake. Drain cleaners can be classified in two categories: chemical, or device.
If a single sink, toilet, or tub or shower drain is clogged the first choice is normally a drain cleaner that can remove soft obstructions such as hair and grease clogs that can accumulate close to interior drain openings. Chemical drain cleaners, plungers, handheld drain augers, air burst drain cleaners, and home remedy drain cleaners are intended for this purpose.
If more than one plumbing fixture is clogged the first choice is normally a drain cleaner that can remove soft or hard obstructions along the entire length of the drain, from the drain opening through the main sewer drain to the lateral piping outside the building. Electric drain cleaners and sewer jetters are intended for this purpose.
Each type of drain cleaner has advantages, disadvantages, and safety considerations as described below.
Something about bathtub
A bathtub, bath or tub (informal) is a large container for holding water in which a person may bathe. Most modern bathtubs are made of acrylic or fiberglass, but alternatives are available in enamel on steel or cast iron; occasionally, waterproof finished wood. A bathtub is usually placed in a bathroom either as a stand-alone fixture or in conjunction with a shower.
Modern bathtubs have overflow and waste drains and may have taps mounted on them. They are usually built-in, but may be free-standing or sometimes sunken. Until recently, most bathtubs were roughly rectangular in shape but with the advent of acrylic thermoformed baths, more shapes are becoming available. Bathtubs are commonly white in colour although many other colours can be found. The process for enamelling cast iron bathtubs was invented by the Scottish-born American David Dunbar Buick.
Two main styles of bathtub are common:
Western style bathtubs in which the bather lies down. These baths are typically shallow and long.
Eastern style bathtubs in which the bather sits up. These are known as ofuro in Japan and are typically short and deep.
History of central heating
The ancient Greeks originally developed central heating. The Temple of Ephesus was heated by Flues planted in the ground and circulating the heat which was generated by fire. Some buildings in the Roman Empire used central heating systems, conducting air heated by furnaces through empty spaces under the floors and out of pipes in the walls?a system known as a hypocaust.23
The Roman hypocaust continued to be used on a smaller scale during late Antiquity and by the Umayyad caliphate, while later Muslim builders employed a simpler system of underfloor pipes.4
After the collapse of the Roman Empire, overwhelmingly across Europe, heating reverted to more primitive fireplaces for almost a thousand years.
In the early medieval Alpine upland, a simpler central heating system where heat travelled through underfloor channels from the furnace room replaced the Roman hypocaust at some places. In Reichenau Abbey a network of interconnected underfloor channels heated the 300 m? large assembly room of the monks during the winter months. The degree of efficiency of the system has been calculated at 90%.5
In the 13th century, the Cistercian monks revived central heating in Christian Europe using river diversions combined with indoor wood-fired furnaces. The well-preserved Royal Monastery of Our Lady of the Wheel (founded 1202) on the Ebro River in the Aragon region of Spain provides an excellent example of such an application.