Choose a way (secondary pressurization or tap water supply), briefly explain the composition and operation flow of water supply equipment, and then complete a 9-story building.

1. The basic components of secondary water supply (for example, pressure superposition) are: (from municipal pipeline to residential pipeline) inlet pump house pipeline-inlet main valve-backflow preventer -(Y-type) filter-flexible connection (expandable to reduce vibration, but it is not recommended to add too much)-slow flow pipe-vacuum suppressor-inlet pressure gauge (electrical contact).

Second, the operation process: when the municipal pipe network pressure meets the user's water pressure, the water pump will not start, and the water will enter through the bypass pipe and be directly supplied to the user; When the municipal pipe network pressure can't meet the water pressure, the pump starts. At this time, the function of the slow-flow pipe is mainly to prevent the pump from directly pumping water from the pipe network to generate negative pressure and play a role in circulation. The function of pressure tank and pressure stabilizing pump is mainly to maintain pressure with small flow at night, so as to avoid frequent start-up of the pump due to small water flow at night and prolong the service life of the pump. The control cabinet is mainly composed of PLC, frequency converter, meter and power switch, and the water pump is in the working state of frequency conversion or power frequency mainly through sensors or electric contact pressure gauges.

The third and ninth floors should determine whether to choose secondary water supply according to the pressure of local municipal pipe network and terrain height. If the buried depth of the municipal pipe network is close to the height of the negative floor, and the pressure of the municipal pipe network is not less than 3.5 kg, the direct supply is basically met, and there is no need to add superimposed secondary water supply equipment. If the floor is built in a higher place and negative pressure needs to be increased, the following selection design can be carried out:

(1) According to the number of people in the residential area, the number of people below 5,000 is calculated according to the design flow calculation method of domestic water supply for residential buildings, and the parameters adopted according to the situation of residential areas are as follows (taking data as an example):

Residential category: ordinary residential category II.

Water quota: 250L/ (person. d)；

Number of people per household: 3.5;

Water supply equivalent per household: 4;

Total number of households in the community: 8 18 households;

Hourly variation coefficient: 2.5;

Water consumption time: 24 hours;

Calculate the design flow q≈24 (liter/second).

(2) Calculate the lift according to the height difference+outlet pressure at the most unfavorable point+loss along the way.

Taking the building with the highest terrain and the farthest distance as the most unfavorable water outlet reference point; (This data already includes the height difference between the center line of the water pump and the center line of the water inlet pipe of the farthest building);

The most unfavorable water outlet point is 1 1m water column. (The water outlet pressure at the most unfavorable point can reach 0. 1 1 MPa)

According to the pipe diameter, material, velocity and distance, the local head loss is estimated to be 30%.

Fourth, cost estimation. The price of secondary water supply equipment is different in different low areas. Take Qingdao as an example here. Qingdao Q=39m? /h, H=47m price of laminating equipment1.6,000 ~ 200,000. The power consumption of equipment can be calculated according to the law of domestic water consumption in residential areas and W =γQ H Tα/( 102η). For example, the daily power consumption of equipment w = γ qht α/(102 η) =1kg/l× 8.3l/s× 45m× 24h×1.0/(102× 0.45) =/kloc.