消声器，压缩空气自动排水器的原理及种类。

1.消声器的功能。

1. Function of muffler.

气动系统中，压缩空气经换向阀向气缸等执行元件供气，动作完成后，又经换向阀排气，由于阀的气路复杂且十分狭窄，压缩空气以接近声速的流速从排气口排出，空气急剧膨胀和压力变化产生高频噪声。

In the pneumatic system, the compressed air is supplied to the cylinder and other executive elements through the directional valve. After the action is completed, the compressed air is discharged through the directional valve. Because the gas path of the valve is complex and very narrow, the compressed air is discharged from the exhaust port at a speed close to the sound speed. The air expands rapidly and the pressure changes produce high-frequency noise.

排气噪声与压力、流量和有效面积有关，当阀的排气压力为0. 5 MPa时可达100dB以上，而且执行元件速度越高，流量越大，噪声也就越大，此时，必须用消声器来降低噪声。消声器通过对气流的阻尼或增加排气面积等方法，来降低排气速度和排气功率，从而达到降低噪声的目的。

The exhaust noise is related to the pressure, flow rate and effective area. When the exhaust pressure of the valve is 0.5 MPa, it can reach more than 100 dB. Moreover, the higher the speed of the actuator, the greater the flow rate, and the greater the noise. At this time, the muffler must be used to reduce the noise. The muffler can reduce the exhaust speed and power by damping the airflow or increasing the exhaust area, so as to reduce the noise.

2. 消声器的分类。

2. Classification of muffler.

根据消声原理不同，有吸收型、膨胀干涉型和膨胀干涉吸收型3类。

According to the principle of noise elimination, there are three types: absorption type, expansion interference type and expansion interference absorption type.

(1)吸收型消声器它是利用吸声材料消声的。吸收型消声器具有良好的中、高频消声性能，尤其是高频噪声，消声效果大于15 dB。适合气动系统使用。

(1) Absorption type muffler is made of sound absorption material. The absorption type muffler has good performance of middle and high frequency noise elimination, especially high frequency noise, and the noise elimination effect is more than 15 dB. Suitable for pneumatic system.

(2)膨胀千涉型消声器它的工作原理是使气体膨胀相互干涉而消声。主要用于中：低频，尤其是低频噪南。

(2) Its working principle is to make gas expansion interfere with each other to eliminate noise. It is mainly used to eliminate medium and low frequency noise, especially low frequency noise.

(3)膨胀千涉吸收型消声器这种消声器的消声效果好，低频可消声20dB,高频可消声45dB。

(3) This kind of muffler has good noise elimination effect. It can eliminate 20dB at low frequency and 45dB at high frequency.

选用消声器时，应合理选择通过消声器的气流速度。对于一般系统可采取6~10m/s，对于高压排空消声器则可设定20m/s的气流速度。

When choosing the muffler, the airflow velocity through the muffler should be selected reasonably. 6 ~ 10m / s for general system and 20m / s for high pressure exhaust muffler.

3.压缩空气自动排水器。

3. Compressed air automatic drainer.

随着对空气净化要求的提高，利用人工的方法定期排污已不可靠，在一些场合不便于人工操作。因此自动排水器得到广泛应用。

With the improvement of air purification requirements, it is not reliable to use manual method to discharge sewage regularly, and it is not convenient for manual operation in some occasions. Therefore, automatic drainer is widely used.

自动排水器用于排出管道、油水分离器、储气罐及分水过滤器中的积水。自动排水器必须垂直安装。在使用过程中，若自动排水器出现故障，可用手动操纵杆打开阀门放水。

The automatic drainer is used to drain the accumulated water in the pipeline, oil-water separator, gas storage tank and water separation filter. Automatic drainer must be installed vertically. In the process of use, if the automatic drainer fails, the manual control lever can be used to open the valve to drain water.