The Faucet Aerator Guide
The faucet aerator is usually installed at the water outlet of the faucet, commonly known as the aerator, water outlet, or faucet flow regulator. This guide makes a comprehensive summary of the principle, structure, function, size, etc. of the faucet aerator.
History of Faucet Aerators
Early faucets were not equipped with aerators, as shown in the following figure.
In the early days, people used water like this: when the faucet was turned on, water would rush out of the outlet at once, with a high flow rate and no constraints on the direction of the initial velocity. The water flow was not linear but approximated a cone with an irregular surface. Water is often sprayed to unnecessary places and even splashed on the user.
Such faucets can cause some problems：
The first is wastewater. The water supply pressure in general residents' homes is about 0.3MPa. Once the faucet is turned on, the water is already at the maximum flow rate. The adjustment range is limited, and the water flow is not constrained, which leads to the ineffective use of some water flows. For example, when washing vegetables, a large and unconstrained water flow not only wastes water but also does not wash the vegetables clean;
The second is that the shape of the faucet's water outlet is unstable, and the water can easily splash on the user.
The third is that the water outlet has impurities. The impurities in the water supply pipeline will flow out with the water flow, and the water with impurities will be poured out, which also causes a waste of water resources.
The fourth is that the water outlet pressure is not limited. The water outlet pressure is high and will feel painful when it hits the skin.
To solve the problem of water splashing when the faucet is running, great inventors threaded the faucet outlet and screwed a matching metal ring with a smooth inner wall onto the outlet to form a flow regulator for the faucet, as shown in the figure below. This is why the early faucet outlet was called a flow regulator.
To filter impurities in the water, people added stainless steel wire mesh on top of the flow regulator, as shown in the figure below. In this way, the prototype of the bubbler was formed. By appropriately increasing the number of stainless steel wire mesh layers and the hole density (mesh size), the purpose of flow limiting can also be achieved.
In actual use, people have found that the wire aerator surface of the metal structure easily reacts with water and air, resulting in scaling or rust, which will cause poor water flow from the faucet. In addition, the wire mesh aerator has no regulating effect on the water supply pressure. The greater the water supply pressure, the greater the water flow from the faucet, which affects people's comfort. The research and development of aerator products started in Europe. Through decades of practice and research, companies have found that plastic materials have greater room for precision processing and product performance improvement. Nowadays, more manufacturers choose POM plastic as the main material for faucet aerator products, as shown in the figure below.
What is the purpose of faucet aerators?
1. Filtration: The aerators can filter sand and impurities in the water.
2. Water saving: The bubbler can make the water flow and air fully contact to form a foaming effect, thereby reducing water consumption. Generally, a faucet with an aerator installed can save about 50% of water compared to a normal faucet.
3. Splash prevention: The water flow will become softer after mixing with the air, reducing the impact force. It can prevent water from splashing everywhere, and it can also play a good noise reduction effect.
How does a faucet aerator work?
The principle of the faucet aerator is to change the flow of water, increase the contact area between air and water, and allow the flowing water and air to mix fully, thereby generating bubbles. With the addition of air, the flushing force of water is greatly improved, effectively reducing water consumption and saving water.
The gas mixing process of the faucet aerator is as follows:
The first step: air enters the aerator net (as shown in the white piece in the figure below), and the water flow is broken up and mixed with the air;
The second step: through the next layer or two layers of filter grids, the water and air are mixed and sprayed out evenly to form a water flow.
The mixing result is shown in the figure:
The basic structure of the faucet aerator
The actual disassembly of the bubbler is shown in the picture:
First row from left: white grille, gray grille, white bubbler net;
Second row from left: pink current limiting plate, transparent filter net, shell.
Faucet aerator classification
Common faucet aerators are divided into two types: constant flow type and limited flow type. In North America and Australia, faucets must use constant flow aerators to meet local water conservation standards. Regarding usage effect, constant flow aerators have smaller fluctuations under different water supply pressures than limited flow aerators.
Constant flow type aerator
There are two working principles of constant-type aerators.
One is to achieve the constant flow effect by deforming the rubber ring by water pressure (the greater the water pressure, the more the rubber is compressed), as shown in the figure.
Another method is to use the principle of water pressure deformation of metal gaskets to control water flow, as shown in the figure. This design is very good. Perhaps the effect of using metal sheets to limit flow is better than rubber.
Flow-limiting aerator
The core working principle of the flow-limiting aerator is as follows: the filter (as shown in the following two pictures) has a large hole at the water inlet end and a small hole at the water outlet end (the following two pictures are the inlet and outlet sides of the flow-limiting plate taken at equal distances). This design is used to limit the water flow rate of the faucet.
Although products with rubber ring current limiting structure and metal gasket current limiting structure can meet the standard requirements, metal materials may be better as the core components of the aerator in a longer service life because the water pressure strength of the water supply is much lower than the fatigue strength of the metal. In an environment where cold and hot water are used alternately, the aging speed of rubber will be higher than that of metal.