, Product performance and use: throttle by changing the length of the throttle cross-section or throttling valve controlling fluid flow. The throttle valve and check valve in parallel can be combined into a one-way throttle. Throttle valves and one-way throttle is a simple flow control valve, with the quantitative pump hydraulic system, the throttle valve and pressure relief valve, can be composed of three throttle speed control system, that is, into the oil line Throttling Speed system, the return oil throttle speed control system and bypass throttle speed control system. The throttle flow negative feedback function, the speed can not compensate for load changes caused instability is generally used only for load changes little or less demanding speed stability occasion. Second, the throttle has the following characteristics: 1, the structure is relatively simple, easy to manufacture and maintenance, and low cost. Regulation accuracy is not high, and can not be adjusted to use. 3, the sealing surface is easily eroded, not for cutting the media used. 4 tightness poor. Throttle valve according to the way of the channel can be divided into two kinds of straight-through and angle; shape by opening and closing parts, needle, groove-shaped window-shaped three. Throttle valve installation and maintenance should note the following: The valve often need to operate, and therefore they should be installed in an easy position operation. Installation should pay attention to the media with the valve body as the arrow in the direction consistent.