Review the thinking questions, what are the common ways of building water supply?

Composition, classification and water supply mode of building water supply system

The water supply and drainage system of general buildings includes water supply system and drainage system, which is an indispensable and important part of any building. The water supply system is mainly composed of water inlet pipe, water meter node, water supply pipeline, water distribution device and water equipment, control accessories, pressurization and water storage equipment, etc.

1. Composition of water supply system

(1) introduction pipe. The water supply pipe section that attracts buildings from the outdoor water supply pipe network is called water inlet pipe, also called water inlet pipe.

(2) Water meter node. The water meter installed on the water inlet pipe and its valves and drainage devices arranged before and after are called water meter nodes. Among them, water meter is used to measure the water consumption of buildings, and flowmeter is commonly used; Valves installed before and after the water meter are used to close the pipeline when the water meter is overhauled and replaced, and drainage devices are used to empty the pipe network when the water meter is overhauled. In order to ensure the accuracy of water meter measurement, water needs to flow smoothly through the water meter, so there should be straight pipe sections that meet the product standards before and after the installation of the water meter. In order to prevent the water meter from freezing and cracking in cold areas, the water meter well can be located in a heated room.

(3) Water supply pipeline. Water supply pipeline system is an important part of waterway, which is mainly composed of horizontal main pipe, vertical pipe and branch pipe. Steel pipes and cast iron pipes, steel-plastic composite pipes with the advantages of steel pipes and plastic pipes, and aluminum-plastic composite pipes with aluminum alloy as the skeleton and polyethylene as the inner and outer walls of pipes are mostly used.

(4) Water distribution device and water equipment. The water distribution device includes faucets and water equipment of various sanitary wares, and the water equipment mainly includes water equipment for production, life and fire fighting.

(5) Control accessories. Mainly refers to all kinds of valves in the pipeline system to adjust the water quantity and pressure, control the direction of water flow and facilitate the maintenance of pipelines, instruments and equipment. Commonly used valves are globe valve, gate valve, butterfly valve, check valve, liquid level control valve, safety valve, etc.

(6) pressurization and water storage equipment. When the pressure of municipal water supply network is not enough to meet the normal water demand of buildings, or when buildings have high requirements for safe water supply, it is necessary to set up pressurized water storage equipment such as water pump, pneumatic water supply device, water tank and reservoir in the water supply system.

2. Classification of water supply system

Building water supply systems can be divided into three categories according to their uses: domestic water supply system, production water supply system and fire water supply system.

(1) domestic water supply system. Mainly used for drinking, washing, cooking and other domestic water, the water quality must meet the national drinking water quality standards and hygiene standards.

(2) Production water supply system. It mainly supplies the cooling of production equipment, the washing of raw materials and products, and the production water needed in the manufacturing process of various products. Production water should provide the required water quality, quantity and pressure according to the process requirements.

③ Fire water supply system. It mainly provides fire water for all kinds of fire fighting equipment, which has low requirements for water quality, but it must ensure sufficient water and water pressure according to the building fire protection code.

3. Water supply mode

Water supply mode is the water supply scheme inside the building, which can usually be divided into direct water supply mode, water tank water supply mode, water pump water supply mode, water tank water pump combined water supply mode, air pressure water supply mode, district water supply mode and quality water supply mode.

(1) Pump water supply mode uses a feed pump to provide domestic water with a certain pressure to end users at different heights, which is often used in multi-storey buildings or small high-rise buildings. When the water consumption inside the building is large and uniform, the constant-speed water pump can be used for water supply; When the water quantity in the building is uneven, one or more pumps should be used to supply water at variable speed.

(2) When the external water supply pipe network pressure is often lower than or can not meet the water pressure required inside the building, and the indoor water consumption is uneven, it is appropriate to adopt the combined water supply mode of water tank and water pump. Usually, a high-level water tank can be set on the top floor of a building, or water tanks can be set at different heights, and then the water from the low-level water supply pipe network or reservoir is pumped to the high-level water tank, and then the high-level water tank supplies water to the water supply pipe network, and finally the domestic water is delivered to users. This water supply method is suitable for multi-storey buildings, small high-rise buildings and high-rise buildings. In some buildings, the lower floor adopts direct water supply, and the upper floor adopts combined water supply of reservoir, water pump and high-level water tank. This mode, also known as district water supply mode, is one of the commonly used water supply modes for high-rise buildings at present.

(3) The building water supply mode with high water tank is also called gravity water supply mode. In this mode, the water supply pressure is relatively stable, and there is a water storage device, so the water supply is safer. However, due to the stagnant water function of the water tank, the water quality can be reduced, and the weight of the water tank is large, which increases the bearing capacity of the building.

(4) Pneumatic water supply refers to installing a pneumatic water supply device, such as a pneumatic water tank, in the water supply system, and using the compressibility of gas in the device to realize pressurized water supply. The function of pneumatic water tank is equivalent to the high-level water tank in gravity water supply mode, but its position can be set at high or low place according to needs, which can avoid the shortcomings of gravity water supply system with water tank on the roof. If constant pressure water supply is needed, water pump units or pneumatic water tanks can be set in the water supply system. By collecting and adjusting the pressure signal, the rotating speed of the water pump or the opening of the outlet valve of the pneumatic water tank can be controlled to meet the user's requirements for water supply pressure. Frequency conversion and constant pressure water supply is a commonly used water supply method at present, which not only saves energy, but also saves building area. The rotation speed of the water pump is automatically adjusted by the frequency converter, so that the water supply varies with the change of water consumption, thus keeping the pressure of the water supply system constant.