It includes both Pip drains and supervising the work performed after the flooding of the city by heavy rains and repair of hydraulic failure in flats and houses and installation of new sanitary facilities.
An elbow is a pipe fitting installed between two lengths of pipe or tubing to allow a change of direction, usually a 90° or 45° angle, though 22.5° elbows are also made.
The ends may be machined for butt welding, threaded (usually female), or socketed, etc.When the two ends differ in size, the fitting is called a reducing elbow or reducer elbow. Elbows are categorized based on various design features as below: Long Radius (LR) Elbows ? radius is 1.5 times the pipe diameter Short Radius (SR) Elbows ? radius is 1.0 times the pipe diameter 90 Degree Elbow ? where change in direction required is 90° 60 Degree Elbow ? where change in direction required is 60° 45 Degree Elbow ? where change in direction required is 45° A 90 degree elbow is also called a "90 bend" or "90 ell". It is a fitting which is bent in such a way to produce 90 degree change in the direction of flow in the pipe. It is used to change the direction in piping and is also sometimes called a "quarter bend". A 90 degree elbow attaches readily to plastic, copper, cast iron, steel and lead.
A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways.
This is called a check valve, as it prevents or "checks" the flow in one direction.Modern control valves may regulate pressure or flow downstream and operate on sophisticated automation systems. Źródło: https://en.wikipedia.org/wiki/Valve.