重慶升降平臺下降靠自身重量為動力，將活塞下部的油壓出去，自身漸漸下降。Ningbo lift platform down by its own weight as the driving force, the lower part of the hydraulic pressure out of their own, gradually decreased.

所以重慶升降平臺活塞下部的油排出去的速度決定了下降的快慢，一般油缸的下部的進油管路上按有多種閥其中有一個電磁節流閥（其本質是電磁閥與節流閥二閥合一）。So Ningbo lifting platform at the lower part of the piston of the oil drain rate determines the speed of decline, the bottom of the cylinder inlet pipe by a variety of valve and one electromagnetic throttle valve (the essence of electromagnetic valve and a throttle valve two valve one).

其作用是：電磁閥用于控制節流閥，節流閥用于控制油管內液體進出油量的大小。The role of the solenoid valve is used to control the throttle valve and the throttle valve is used to control the amount of oil in the oil pipe.

一般節流閥閥體上都安有調整油量的旋鈕，就像音量旋鈕或水龍頭旋鈕。所以你可以通過調整重慶升降平臺節流閥上的旋鈕來調整下降速度。 General throttle valve body on the safety knob to adjust the amount of oil, like the volume knob or faucet knob. So you can adjust the speed by adjusting the knob on the throttle valve of the Ningbo landing platform.