译文：
通过对流体噪音的分析，结合现场使用流量控制阀后噪音的调查，利用流速、压差及多级降噪的理论生产出低噪音的产品。 我公司的主导产品——自力式流量控制阀，自93年问世到目前已整整十个年头了，在这十年中供热界的同行们从不认识到认识，从片面了解到系统应用，使得自力式流量控制阀在供热方面发挥了一定的作用。 在这十年中我公司的自力式流量控制阀进行了两次重大的改进。从93年Ⅱ 型产品使用到98年，{dy}个5年里，由于老Ⅱ 型体积较大且安装位置受限制，为适应用户的需求在99年我们对老产品进行了改进。生产出即可保证控制性能又可任意角度安装，并且体积缩小了40％；到2002年第二个5年里，好多用户反映安装使用后噪音比原来增大了，特别是安装在室外架空管线上。针对这种情况我们又组织技术人员进行专题研究开发，经过近四个月上千次的试验，我们目前已生产出低噪音、带锁闭、便于调节的流量控制阀。噪音由原来的65～75dB降到45～55dB，可满足不同用户的需求。下面就我们在研制过程中得到的一点体会总结出来，供同行们参考。 一、 噪声源分析 在供热系统中离不开泵、管道和阀门，可这些又都是产生噪声源的设施。 1、先说管道，液体流经管道时，由于湍流和摩擦激发的压强扰动就会产生噪声，特别是当雷诺数Re>2400时的湍流状态，这种含有大量不规则的微小旋涡的湍流，可以说自身就处于“吵”的状态。尤其流经节流或降压阀门、截面突变的管道或急骤拐弯的弯头时，湍流与这些阻碍流体通过的部分相互作用产生涡流噪声，其声功率级（dB）随流速的变化关系可表示为：△Lw=60lg，若管路设计不当还可以产生空化噪声； 2、再说阀门，带有节流或限压作用的阀门，是液体传输管道中影响{zd0}的噪声源。当管道内流体流速足够时，若阀门部分关闭，则在阀门入口处形成大面积扼流，在扼流区域液体流速提高而内部静压降低，当流速大于或等于介质的临界速度时，静压低于或等于介质的蒸发压力，则在流体中形成气泡。气泡随液体流动，在阀门扼流区下游流速逐渐降低，静压升高，气泡相继被挤破，引起流体中无规则的压力波动，这种特殊的湍化现象称为空化，由此产生的噪声叫空化噪声。在流量大、压力高的管路中，几乎所有的节流阀门均能产生空化噪声，这种空化噪声顺流而下可沿管道传播很远，这种无规则噪声能激发阀门或管道中可动部件的固有振动，并通过这些部件作用于其它相邻部件传至管道表面，产生类似金属相撞产生的有调声音。空化噪声的声功率与流速的七次方或八次方成正比，因此为降低阀门噪音可采用多级串接阀门，目的是逐级降低流速。如我们经常使用的截止阀，采用的是低进高出的流向，因此当流体流经阀腔时，就会在控制阀瓣的下面（即扼流区内）形成低压高速区，产生气泡。通过阀瓣后又形成高压低速区，气泡相继被挤破产生空化噪音。 根据以上分析可见管道噪声、阀门噪声都与液体流动的状态有关，换句话说即与压差和流速有关。 二、流速、压差所产生的噪声调查 下面是我们实地调查的数据。天津碱厂朝阳楼小区换热站，供热面积26.5万平方米，管线敷设方式：室外架空，该换热站分四个环路供出。南区管径DN250所供面积13.2万平方米；北区管径DN250所供面积10.8万平方米；春风里管径DN200，所供面积12000平方米；34＃楼管径DN150，所供面积8012平方米。住户反映34＃楼和春风里安装控制阀后噪音较大。2003年3月3日我们到现场进行测试（设备超声波流量计、噪声计），数据如下： 实测室内噪声34＃楼、2、3单元57 dB；春风里1＃楼1、3单元58 dB～60 dB，而南区1＃楼1、3、5单元为45～47 dB。从以上数据看，虽然各入户单元流速都没超过设计要求，但由于相对单体流速太快、压差较大，造成在控制阀处产生空化噪声。34＃楼的压差为0.06Mpa,而南区1＃楼的压差为0.02 Mpa，形成局部流速快和压差大的另一个原因是34＃楼和春风里距换热站的距离较近。最远端用户入口距离350米左右，而南北区最远端用户达1000米左右，同是一个系统距离相差悬殊，因此造成入户压差相差很大，流速相差也大。由于管线又是架空安装这种空化噪声与支架又产生共振使得噪声传递到室内，此种情况在辽河油田曙光作业区也有发生。不单单是架空管线，埋地管线也可以产生空化和湍流摩擦噪声。如天津北辰区的一个供热小区是直埋管线。安装流量控制阀后噪声明显增加，实测室内达65 dB。询问用户说以前也有，但没现在大，将控制阀拆除后，实测室内还达58 dB，究其原因也是由于热网平衡不好，个别单体压差大、流速过快。前面说过空化噪声和声功率与流速的七次方或八次方成正比，因此，流速虽然只差一点点，但噪声却增加很大。鉴于以上的情况，对朝阳楼小区的34＃楼我们采取了逐级降压或者说逐级降低资用压头和流速的办法。首先将支干线的出口阀门（DN150）进行了调整，又将单元入户阀门进行了调整。再测34＃楼入户压差控制在0.03～0.05Mpa之间，再测室内噪音2单元102已降至35 dB，3单元101降至40 dB，已满足需求。 三、 降噪控制阀的产生 1、前面已经提到声功率级随流速的变化关系为△Lw=60lg，而由△P=KVS·G2又可得出V=，因此可见当流量系数（KVS）一定，流通截面积(πR2)一定时，声功率级也可表示为△Lw=60lg，而自力式流量控制阀又是基于调整压差达到控制流量的目的。那么如何既保证压差又达到降噪的目的，根据以上实测数据及理论分析，我们采用了多级降压的结构。首先将手动阀瓣改变为斜旋塞形，使得流通性能即可保证又可降低流速，这是{dy}级； 2、其次将自动阀瓣改为双弧面，双阀瓣结构，流体流动时先通过上阀瓣上圆弧面，再通过下圆弧面即方便流体通过又可降低流速，这是第二级； 3、然后流体再通过下阀瓣的上圆弧面和下圆弧面这是第三级。同时在自动阀瓣上还带有侧筋板即可导流，又可xx流体中形成的气泡。为了xx因扼流产生的低压高速区，我们开始时在控制阀入口和手动控制处增加了阻尼网降低流速，减少扼流，可经过试验不可行，因为阻尼网虽然耐腐蚀（采用了不锈钢材料），但由于网眼直径的限制很容易引起堵塞；我们又将自动阀瓣改变为梳齿形，目的是为了减少高速区内形成的气泡。但由于梳齿的形状和强度不利于长期使用，因此也没有采用。 4、{zh1}还是采取了多级降噪的结构。我们经过近1000多次的试验不断改进，使控制阀的噪声从原来的65～75dB降到现在的45～55 dB。 总结 通过这两次技术改造使得自力式流量控制阀在使用范围上又得到了进一步扩大。目前我们的降噪阀已成批生产，并已有十多家用户定货。一种专利产品一般寿命为30～50年。自力式流量控制阀在我国已问世十多年，已逐渐成为通用产品。如何让供热用户更好地了解使用该产品是我们继续工作的方向，我们还将不断努力，开发新的产品为热用户服务。

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原文：
The analysis of fluid through the noise, combined with on-site noise level after the use of flow control valve of the investigation, the use of velocity, pressure and multi-level theory of noise reduction to produce low-noise products. My company's leading products - self-operated flow control valve, since the 93 came to a full 10 years now, and in this decade in the heating sector colleagues did not know that knowledge learned from a one-sided system applications, makes the self-operated flow control valve in heating played a certain role. In this decade, my company's self-operated flow control valve carried out two major improvements. Ⅱ products from 93 years to 98 years using the first 5 years, because of the large size of the old type Ⅱ and the installation location is restricted to meet the needs of users in 99 years, we have the old product is improved. The control performance can be guaranteed to produce any angle can also install, and the volume reduced by 40%; to 2002 the second five years, a lot of users have installed the original noise ratio increases after use, especially outdoor aerial installed in the pipeline on. To address this situation we have organized technical personnel to conduct special research and development, after nearly four months, thousands of experiments, we now have to produce low-noise, with locking, easy to adjust the flow control valve. Noise from the original 65 ~ 75dB down to 45 ~ 55dB, can meet the needs of different users. Here's the process of researching, we get a little experience summed up for the peer as a reference. 1, noise source analysis Can not be separated in the heating system pumps, piping and valves, but these both are the facilities generate noise sources. 1, first said the pipeline, the liquid flows through the pipeline, due to turbulence and friction to stimulate the pressure disturbance will generate noise, especially when the Reynolds number Re> 2400 when the turbulent state, which contains a large number of small irregular vortex turbulence can be said that they themselves in a "noisy" state. In particular, flows through the throttling or pressure valve, cross-sectional mutation or rapid-bend of the elbow pipe when the fluid turbulence with these obstacles through the part of the interaction of eddy-current noise, the sound power level (dB) vs. air velocity relationship could be is expressed as: △ Lw = 60lg, if the pipes are poorly designed can produce cavitation noise; 2, again the valve, with the role of throttling or pressure limiting valves, liquid transmission pipelines that affect the largest noise source. When the pipe flow rate sufficient, if the valve partially closed, then the choke valve at the entrance to the formation of a large area, in the choke area of liquid flow rate increased and the internal static pressure lowering, when the flow rate is greater than or equal to the critical speed media , static pressure less than or equal to the evaporation of media pressure, the formation of bubbles in the fluid. Bubble with the liquid flow velocity in the downstream of the valve choke area gradually reduced, static pressure rise, have pushed the bubble broke, causing the pressure of fluid random fluctuations in the turbulence of this particular phenomenon is known as cavitation, thus called the noise generated by cavitation noise. In the flow of large, high-pressure pipeline, almost all of the throttle gate can produce cavitation noise, this cavitation noise down the river can be spread very far along the pipeline, which can stimulate the valve noise-free rules or pipes can be moving parts of the natural vibration, and through the role of these components in other parts spread to adjacent pipe surface, resulting in a collision similar to the metallic sound produced by a tone. Acoustic cavitation noise power and velocity of seven or the eight sides is proportional to the noise so the valve can be used to reduce the multi-stage tandem valves, the purpose is to progressively reduce the flow rate. As we often use the cut-off valve, using the low, sell high flows, so that when fluid flows through the valve chamber, they will flap in the control valve below (ie, choke the area) to form low-voltage high-speed zone, creating bubbles. A high-pressure through the valve flap after low-speed zone, have pushed the bubble cavitation noise generated breaking. Based on the above analysis shows the noise pipe, valve noise, the state with the liquid flow is related in other words, with the pressure and flow related. 2, flow rate, pressure generated by the noise survey Here is our field survey data. Tianjin Soda Plant Floor Chaoyang district heat stations, heating an area of 265,000 square meters, the pipeline laying method: outdoor overhead, the heat transfer station in four loop confess. The Southern District diameter DN250 an area of 132,000 square meters are for; North diameter DN250 are available for an area of 108,000 square meters; spring inside diameter of DN200, are available for an area of 12,000 square meters; 34 # F diameter DN150, for an area of 8012 by square meters. Households reflects the House and 34 # spring where the noise level after the installation of control valves larger. March 3, 2003 we went to the scene to conduct testing (equipment, ultrasonic flowmeters, noise meter), as follows: Measured interior noise 34 # F, 2,3 unit 57 dB; spring unit inside a # 1,3 F, 58 dB ~ 60 dB, while the South 1 # F, 1,3,5 unit is 45 ~ 47 dB. From the above data shows that, although various households cell velocity in no more than the design requirements, but because of the relative monomer flow too fast, a larger pressure difference, causing the control valve cavitation noise. 34 # building pressure for 0.06Mpa, Southern District, a # floor pressure of 0.02 Mpa, the formation of local velocity and pressure quickly Another reason is the large buildings and 34 # spring where the short distance from the heat exchange station . Of the most remote users to import a distance of 350 meters, while the north and south areas of the most remote users to 1,000 meters, the same distance from a system are significant differences between households resulting pressure difference between the large velocity difference is also large. As the pipeline is an overhead installation of such cavitation noise and stent resonance makes the noise again passed to the interior, such a case the dawn of the Liaohe oil field operations areas also occur. Is not only elevated pipelines, buried pipelines can also produce cavitation and turbulence friction noise. Such as the North Star District, Tianjin, a district heating pipeline is buried. After the installation of flow control valve noise, a marked increase in the measured indoor up to 65 dB. Asks the user that there before, but did not now large, will control the valves removed, the interior was also measured up to 58 dB, The reason is due to poor balance of heat supply network, individual monomer pressure big flow rate too fast. As I said before acoustic cavitation noise power and velocity of the seven or the eight sides is proportional, therefore, flow rate though only narrowly, but the noise has increased greatly. In view of the above situation, the Chaoyang district of 34 # F, F, we have taken a step-down or one level lower level-funded with the pressure head and flow approach. First of all branch lines will be the export of valves (DN150) was adjusted in turn valves adjusted unit households. Test-retest 34 # F-home pressure controlled at 0.03 ~ 0.05Mpa between the two test-retest interior noise has been reduced to 102 units 35 dB, 3 units 101 to 40 dB, has been to meet demand. Third, control valve noise generation 1, as already mentioned the sound power level with changes in velocity relationship △ Lw = 60lg, by △ P = KVS · G2 can also arrive at V =, is thus clear that when the flow coefficient (KVS) will, circulation, cross-sectional area (πR2 ) amount of time, the sound power level can also be expressed as △ Lw = 60lg, while the self-operated flow control valve is adjusted based on the pressure to control flow purposes. So how are we going to ensure they achieve the noise differential purposes, according to the above measured data and theoretical analysis, we have adopted a multi-stage step-down structure. First, the manual valve to change the oblique cock-shaped flap, allowing the performance can be guaranteed and can also lower the circulation flow rate, this is the first level; 2, followed by the flap valve will automatically be converted to two-arc, double valve flap structure, fluid flow through the valve when the flap on the first circular surface, then through the next circular surface that can be reduced to facilitate fluid flow through, which is the second level; 3, and then flow under the valve flap and through the upper and lower circular surface circular surface which is the third level. At the same time the automatic valve flap with side ribs still can be diversion, but also eliminate the formation of fluid bubbles. In order to eliminate high-speed low-voltage generated by choke area, we started to control the entry and manual control valve to add the network to reduce flow of the damping to reduce the choke can be tested is not feasible, because the damping Although it resistant to corrosion (stainless steel material used ), but due to restrictions on the diameter mesh can easily lead to plug; we turn the automatic valve flap to change the comb-shaped, designed to reduce the high-speed air bubbles formed in the area. However, comb shape and intensity is not conducive to long-term use, and therefore not used. 4, finally adopted a multi-stage noise reduction structure. After nearly 1,000 times that we continue to improve the pilot, so that control valve noise from the original 65 ~ 75dB down to the present 45 ~ 55 dB. Summary These two technological transformation through self-operated flow control valve allows the use of scope has been further expanded. At present, our noise reduction valve has become a batch production, and has more than 10 clients in ordering. Proprietary products are generally of a life of 30 to 50 years. Self-operated flow control valve in China has been available for 10 years, has gradually become a commonly used products. How to make heating users a better understanding of use of the product is the direction that we continue to work, we will also continue efforts to develop new products for the hot-users.