For supply with gas of all consumers in the territory of the cities the distributive gas network is under construction, gas control points or installations (GRP are equipped and the GRU), constructs control points and other equipment, necessary for operation of gas pipelines.
The first type of filters is intended for gas expenses, small to 3800 m3/h. The second type of filters is intended for the admission of heavy expenses of gas. The number after FG means filter capacity in thousands of cubic meters an hour.
At the baking of bread and confectionery making a main type of production of these consumers of gas it is necessary to consider a difference in consumption of heat on different types of production. The norm of baking of bread per day on 1000 inhabitants is accepted at a rate of 0,6 0,8 tones. This norm includes pastries and black and white loaf, and also baking of confectionery. Precisely to define how many what type of production inhabitants very difficult consume. Therefore the general norm can be divided 0,6 0,8 tons into 1000 inhabitants conditionally in half, considering that bakeries and bakeries equally bake black and white loaf. The baking of confectionery can be considered separately, for example, of 0,1 tons on 1000 inhabitants per day.
Emergency operation of operation of the gas pipeline comes when the gas pipeline sites adjoining a food point In our case refuse work these are sites 1 and 1 Food of consumers in emergency operation has to be carried out on a deadlock network with a condition of obligatory maintenance of pressure of gas at the last consumer of P K = 0,25 MPas.
The choice of the equipment of GRP and GRU begins with definition like the gas pressure regulator. After a choice of the regulator of pressure types of safety and locking and safety and waste are defined. Further the filter for purification of gas, and then shutoff valves and instrumentations is selected.
Diameters of sites of the gas pipeline in this mode get out of a of calculations in emergency operation. For each site the greatest of two diameters is accepted. Thus the sizes of diameters on sites of a ring will be the greatest. Further the sizes of diameters monotonously to decrease in the direction of a point of a descent of streams.
The warmth expense for these consumers considers a gas consumption on washing of linen in laundries, on a washing of people in baths, on sanitary processing in dezkamer. Very often in the cities and settlements laundries and baths unite in one enterprise. Therefore the warmth expense for them has to be also integrated.
In GRP it is necessary to support a positive of air not less than 10 °C. For this GRP it is equipped with local system of heating or it is connected to system of heating of one of the next buildings.
The minimum value of a settlement consumption of gas on a site has to be equal to a half of the traveling. For ensuring profitability of system it is necessary to allocate the main directions on which the most part of gas is transported.
e - a specific hour consumption of gas on one person, the m3/chel.ch which is set or calculated if the number of inhabitants (N) consuming gas is known and knows amount of the gas (V) consumed by them in an hour
The shutoff valves from gray cast iron are applied with a working pressure of gas no more than 0,6 MPas. Steel, brass and bronze with a pressure up to 1,6 MPas. Working temperature for pig-iron and bronze fittings has to be not lower than-35 With, for steel not less than-40 Pages.
Pith cranes have the smaller hydraulic resistance, than gates is considerable. They are distinguished on an inhaling of a conic stopper on tension and stuffing, and on a method of accession to pipes - on muftovy and flange.
Pipes make the main part of gas pipelines, on them gas to consumers is transported. All connections of pipes on gas pipelines are carried out only by the welded. Flange connections are allowed only installation sites of the locking regulating fittings.
The industry lets out two PZK types: PKN and PKV. The first should be applied in cases when after GRP or GRU low pressure is supported, the second - an average. Dimensions and type of the valve are defined by pressure regulator type. PZK usually choose with the same nominal diameter, as well as the regulator.