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（1）孔板流量计——导阀——主阀原理。主阀前设置一个流量孔板，导阀感测、比较孔板前后压力差，如压力差大于设定压差，意味着流量超过设定流量，导阀控制主阀做关阀动作。如感测压差小于设定压差，则意味着流量小于设定流量，导阀控制主阀开阀动作。导阀上的设定压差可调，调大调小设定 压差，可以调大调小设定流量。 由于孔板流量计的流量压差对应关系受到前流态影响极重，如果要求流量精度达到10%，则必须阀前有10d以上的直管段，而这一点工程实际中极难保障。另外这种阀出厂后的流量可调范围很小，在保持流量精度的前提下，流量可调比不会超过2：1。 （2）“Kv·=常数”原理，自由弹簧和感压膜构成阀门开关动力系统△P/S=εL S—感膜工作面积，ε—弹簧的胡克系数，L—阀行程 由此可知阀门的每一个行程位置决定△P值的大小，如果阀行程位的Kv与 成反比，则G=Kv· 是恒定值。这一原理的 阀最初做成流量不可调的流量限制器，近年生产的流量可调式一种是做成多管通道，通过堵管调整设定流量；另一种是用一手动阀改变自力阀Kv与行程的关系，但这种办法很难保证Kv与 在每一调整位置的反比关系，造成调整位的流量控制精度不高。另外有的产品用波纹管制作感压膜和自由弹簧的一体化产品，由于 不锈钢波纹管处在流动死区，在水中氯离子含量较高时，极易产生腐蚀。 （3）自力式压差控制阀与手动调节阀阀组原理。这种原理是现在国产流量控制阀最广泛采用的。手动调节阀的每一个开度位置对应一个Kv值，由自力式压差控制阀控制手动调节阀前的压差不变，则G=Kv· 不变，改变流量时只需调整手动调节阀的Kv值。 这种阀的流量控制精度决定于压差控制阀精度，压差 △P=N/S N——弹簧力 S——感压膜工作面积 弹簧力在自力阀的行程内会有变化，但使 H/△L=1/10 H——自力阀{zd0}位移 行程 △L——弹簧的预压缩量 则△P的变化仅为±5%，流量精度可达3%。 这咱自力式流量控制阀的缺点在于阀门有最小工作压差的要求，一般产品要求最小工作压差20KPa，如果安装在最不利回路上，势必要求循环泵多增加2米水柱的工作扬程，所以应采取近端安装，远端不安的办法。用户离热源距离大于 供热半径的80%时就不宜安装这种自力式流量控制阀。 （4）用自力式压差控制阀直接控制流量 户内阻力系数S，在平均供热的前提下是不变值，户内设计流量G，△P=SG2,通过控制户内供回水压差，一样可以控制循环流量，调节控制压差就可调节循环流量。用这种办法调控流量，只是必须借助便携式流量测试仪器如超声波流量计。这种方式对于远端用户，阀门不会增加消耗压头。
“ Self-Control Valve works ”是由提供的阀门行业新闻，译文仅供参考。另外，中国控制阀网还提供相关产品搜索： 、 、 、 、 、 、 、 、 、 、 等。
(1) Orifice Meter - pilot valve - main valve principle. Before the main valve to set a flow orifice, pilot valve sensor, the pressure difference before and after comparison orifice, such as the pressure difference greater than the set pressure, mean flow rate exceeds a set flow, pilot valve control valve off the main valve of action. Pressure difference as being less than the set pressure, the mean flow is less than set the flow valve to control the main valve guide valve opening action. Pilot valve pressure setting on the adjustable Enlarge the small set pressure, you can set the flow of a small flat tone. Because the flow meter orifice pressure by correspondence before the impact of heavy flow, if required flow accuracy of 10%, the valve must be over before the straight section 10d, and this works in practice extremely difficult to protect. In addition, after the flow of this valve factory adjustable range is small, the premise of maintaining the flow accuracy, the flow rate adjusted no more than 2:1 ratio. (2) "Kv · = constant" principle, a sense of freedom laminated springs and valve switching power systems constitute △ P / S = εL S-feeling film work area, ε-spring Hook coefficient, L-valve stroke From this position of valve travel decisions every size of △ P value, if the valve travel position of the Kv and inversely proportional to the G = Kv · a constant value. The principle of non-adjustable valve initially made the flow of traffic limiter, the flow of production in recent years, one is made adjustable multiple channels, adjust the settings by plugging traffic; the other is the valve manually with a valve to change the self- Kv and the relationship between stroke, but this approach is difficult to guarantee that Kv and adjust the position of each inverse relationship, resulting in adjustment of the flow control bit accuracy is not high. In addition, some products being laminated with a corrugated pipe production and free spring of integrated products, as stainless steel bellows in flow dead zone, a high chloride content in water, the highly corrosive. (3) Self-operated pressure control valve and manual valve valve principle. This principle is now flow control valve made the most widely used. Manual control valve opening position of each corresponds to a Kv value, by the Self-control manual pressure control valve before the pressure control valve constant, G = Kv · unchanged, changes only need to adjust the manual flow control valves Kv value. This valve flow control accuracy depends on the precision pressure control valves, pressure △ P = N / S N - spring force S - sense of laminated work area Valve spring force in self itinerary change, but to H / △ L = 1 / 10 H - Self-valve the maximum displacement travel △ L - Pre-compression spring △ P changes are only ± 5%, traffic up to 3% accuracy. It argues self-operated flow control valve of the disadvantage is that the valve has a minimum working pressure requirements, the general minimum working pressure product requirements 20KPa, if installed in the most disadvantaged back on the road, will require that the circulating pump more to increase the work of 2 m water column head, Therefore, installation should be taken to the proximal and distal disturbing way. User from the heat source radius range of more than 80% of heating should not be installed on such a self-operated flow control valve. (4) Self-pressure control valve with direct control flow Indoor resistance coefficient S, the average heating value of the premise is unchanged, indoor design flow G, △ P = SG2, by controlling the indoor supply and return water pressure, as flow control loop, regulating control pressure on the circulation flow rate can be adjusted. In this way control flow, but requires the help of portable test instruments such as ultrasonic flow meter. For remote users in this way, the valve will not increase the consumption of pressure head.
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