Q&A on water supply for high-rise buildings?

Compared with other water consumption, the water consumption of high-rise buildings (especially houses and hotels) is characterized by uneven water consumption, and the time variation coefficient is greater than 2.5. The time of building water consumption is relatively concentrated, which also puts forward higher requirements for high-rise building water supply. The following is the introduction of water supply knowledge of high-rise buildings brought by Construction Network for your reference.

High-rise building water supply question and answer

(1) What are the characteristics of building water supply?

Answer: The water consumption is uneven, and the time variation coefficient is large, generally above 25. Water consumption time is relatively concentrated in several time periods, especially in the morning, and almost no one uses water after midnight.

(2) What is the function and importance of roof water tank?

Answer: ① The water tank can reserve a certain amount of water, which plays the role of regulation, buffering and emergency preparedness.

② Setting the water tank can give full play to the efficiency of the water pump, which works intermittently and saves energy.

(3) What are the characteristics of variable frequency speed regulation water supply equipment?

Answer: ① There is no roof water tank, which belongs to the bottom-up water supply mode.

② By changing the frequency and adjusting the number of motor revolutions, the water supply pressure can be kept constant in a certain range.

③ The water pump runs almost 24 hours, and the downtime is very short, which is not energy-saving and economical.

④ The frequency conversion water supply system can't control the opening, closing degree and switching time of the valve through the program, and water hammer hazards will occur every time the pump is stopped and started.

(4) Why do you want PLC control?

Answer: PLC is a logic program controller, which can control the valve opening and closing time, delay control and sequence control. The whole control process is completely carried out according to the pre-programmed logic program, which can effectively avoid or reduce the damage of water hammer to the system and protect the water pump.

(5) How to determine the size of roof water tank?

Answer: According to our experience, the volume of the water tank should be 10% of the daily water consumption, and the effective regulating volume should not be less than 5% of the daily water consumption.

(6) What are the important problems of non-negative pressure water supply? How to solve it?

Answer: the instantaneous imbalance between the water intake of municipal pipe network and the pumping capacity of pumps. This problem can be solved by adding a draft tube.

(7) How to determine the volume of non-negative pressure water supply draft tube?

Answer: It depends on the pipe diameter, flow rate, water absorption, the longest working time and the shortest downtime of the pump.

Time and other data to determine the volume of the draft tube. The water supply guarantee rate of municipal pipe network is an important parameter.

(8) What are the main requirements of water supply for residential buildings?

Answer: ① uninterrupted water supply; ② The pressure is guaranteed; ③ The water quality is guaranteed.

(9) What kind of equipment property company is the most popular?

Answer: unattended, electricity-saving and money-saving fully automatic water supply equipment property companies are most welcome.

(10) Can the building water supply equipment play the function of frequency conversion and energy saving?

A: I can't play. Because the frequency runs at 60-70% most of the time, the ideal frequency is 80- 100%.

(1 1) How to prevent water pollution in water tanks?

Answer: ① Use a closed water tank to reduce the chance of contact between water and air; (2) the water tank should be as small as possible to reduce the residence time of water in it; (3) changing the direction of water inlet and outlet to make the water rotate and flow, so as to ensure water activity; ④ Ultraviolet disinfection was used.

(12) Can the check valve be cancelled?

Answer: Check valve is a kind of pipe fitting that consumes a lot of energy. It can be cancelled in the automatic water supply system controlled by PLC; Check valves in other systems cannot be cancelled.

(13) Is it okay to share the water tank with the fire department?

A: Yes. In the Code for Design of Tall Buildings, domestic and fire water tanks are allowed to be used.

(14) Can the underground water tank be cancelled?

Answer: The municipal pipe network allows direct access, and it can be cancelled when the municipal water supply pressure is relatively stable.

(15) What is water? Under what circumstances will water samarium appear?

Answer: Water hammer, also known as water hammer, refers to a series of severe hydraulic impact phenomena in pressure pipeline, which are caused by the drastic change of flow velocity and the alternating rise and fall of pressure. Generally, water hammer will occur when the water pump unit stops due to sudden power failure or other reasons, and the water hammer is more harmful when there is a check valve in the system.

(16) What are the operation processes of the water pump?

Answer: ① Preparation and inspection before starting the pump; ② Observe after starting the pump; ③ Check after stopping the pump.

(17) What is the function of the draft tube?

Answer: exhaust in time, adjust, buffer and balance the water inlet and outlet.

(18) What is the reason why the water pump does not supply water?

Answer: ① There is no water in the pool or pipe network; (2) introducing air into the water inlet pipe; (3) The municipal pipe network is short of water (when there is no negative pressure water absorption mode); (4) The impeller of the water pump falls off; ⑤ Impeller cavitation is serious or blocked.

(19) How to call the police when there is no water in the pipe network?

Answer: By monitoring the pressure of the water inlet pipe, if it is negative pressure, start the alarm device.

(20) What are the protective measures for the water tank?

Answer: ① The water tank is sealed and equipped with an automatic exhaust valve at the top to ensure that the water tank is not damaged by water hammer; ② The water tank is lined with FRP for anticorrosion; (3) the form of torque in the direction of water inlet and outlet; ④ Disinfect the effluent with ultraviolet C. ..

(2 1) Why do most designs use variable frequency pumps instead of high-level water tanks?

A: It is relatively simple for designers to adopt variable frequency water pumps in their design. And conceptually, the variable frequency water pump seems to be able to ensure the pressure and adjust the water volume.

(22) What are the common models of valves in the pump room?

Answer: ① Butterfly valve (D7 1X) ② Gate valve (Z4 1T) ③ Electric butterfly valve (DDF) ④ Electric ball valve (DQF) ⑤ Check valve (H44T).

(23) Why is there a mechanically sealed water pump? What are the advantages of mechanical seal water pump?

A: It is the current trend to engage in mechanical sealing of water pumps. The mechanical seal is reliable, watertight, low in wear and easy to maintain.

(24) What is the basis for the selection of feed water pumps in high-rise buildings? What's wrong with the current design?

Answer: Select the pump model according to1-12 times of the maximum hourly water consumption. At present, the design is conservative, and the choice is too large, which is very wasteful. The lift of most pumps is10-15m.

(25) What instruments does the pump room need?

Answer: ① imported vacuum gauge; (2) export pressure gauge; ③ voltmeter; ④ ammeter; ⑤ Water meter.

(26) What are you most afraid of without negative pressure water supply?

Answer: The water pressure in the municipal pipe network is unstable and often fluctuates or is cut off.

(27) What are the requirements for key components?

Answer: The key components must be the products of well-known foreign companies to ensure reliable quality.

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