提高液压水位控制阀稳定运行性之我见

提高液压水位控制阀稳定运行性之我见

2010-03-11 11:16:25 阅读6 评论0 字号:

译文:
1、引言 液压水位控制阀是一种改进了的浮球阀,当水池或水塔内水位下降,浮球阀开启排水时,进水管内有压力水将阀内活塞托起,密封面打开,阀门即开启供水,当水位上升到控制面,浮球阀关闭,活塞下移将密封面封闭,阀门即停止供水,从而达到自动控制水位的目的。因其不耗电能,结构简单,安装施工方便,适用压力广等优势,在各类清水水池(水箱)的水位自动控制有着较为广泛的应用。但是由于水质和水力因素等的影响,液压水位控制阀往往失灵,轻则白白浪费水资源,重则水淹泵房,造成严重后果。提高液压水位控制阀的稳定性,保证安全供水就显得十分重要了。 2、液压水位控制阀的内部结构及作用原理 液压水位控制阀一般由浮球阀,控制管,液压阀主体组成。虽然液压控制阀主体的外观各异,材质不同,有立式和卧式安装形式等,但其内部结构和作用原理却基本相同。液压控制阀的主体由进水腔、出水口、活塞式阀芯、泄压腔、泄压口等组成,见图1。 设进水的水压为P0,泄压腔的压力为P1;活塞式阀芯的重力为G,活塞式阀芯泄压腔端的直径为D1,另一端的直径为D2。连通进水腔和泄压腔的小孔直径的d1,泄压口的直径为d2,活塞式阀芯与阀腔的摩擦力为f,受到的支持力为N。下面以图1中结构示意图一(结构二类似)为例,分析活塞式阀芯的受力情况如下: 设活塞式阀芯受到的合力为F,则阀芯受力矢量式为: F=F1+F2+F3+F4+f+N+G……………………(1) 表达为代数形式如下: F=P0D22π/4+P2(D12π/4- D22π/4)- P1D12π/4±f-G±N =(P0D22-P1D12)π/4±f-G+P2(D12- D22)π/4 ±N =A±f-G±N+B……………………(2) (2)式中A=(P0D22-P1D12)π/4,B=P2(D12- D22)π/4; f的符号与A的符号相反。 当水池或水塔内水位下降,浮球阀开启排水时,进水腔通过小孔d1向泄压腔补水,由于补水孔d1<泄压孔d2,补水能力小于泄压能力,泄压腔的压力P1降低,阀芯支持力N1逐渐减小到消失,进水管内有压力水P0克服活塞式阀芯的重力和摩擦力将其托起,上式F>0,密封面逐渐打开,液压阀门即开启向水池(或水塔)供水。当水池水位上升到控制水面,浮球阀关闭,泄压腔补水能力大于泄压能力,N2逐渐减小, P1上升({zd0}至P0),上式F<0,活塞下移将密封面封闭,阀门即停止供水。液压控制阀在浮球的控制下,从而可以自动控制水位。 3、影响液压水位控制阀稳定运行的因素 3.1液压水位控制阀的安装示意图 3.2泄压腔压力变化 液压控制阀安装投入使用时,(2)式中D1、D2、d1、d2G为已知常数,影响活塞式阀芯运动的力就只有水的压力P0、P1的作用及活塞受到的摩擦力f。一般情况下:D1≥D2,d1≤d2,出水口的压力变化范围为0≤P2<P0,泄水腔压力0<C1(常数) ≤P1≤C2~P0。通过受力分析可以看出,液压阀安全可靠的运行要求泄压腔压力要有适当的变化,当泄压腔压力达到最小时,阀芯能够上升到{zd0}开启度位置;如果液压控制阀的活塞式阀芯坚固,能始终保持泄压腔的密闭并能进水腔口紧密结合,当浮球阀关闭,泄压腔内压力始终能上升到C2(C2约等于P0,且与液压阀结构和安装方式无关),活塞式阀芯能在水压力P1和自身的重力G作用下,克服摩擦力f下降并关闭液压阀。可见泄压腔的最小压力C1是决定液压阀是否能稳定运行的关键因素,泄压腔内压力变化的快慢决定液压阀灵敏性的高低。定义泄压腔内的最小压强C1为液压控制阀稳定运行数。当液压控制阀开启度{zd0},即浮球阀稳定放水时,此时泄压腔内压力P1=C1。此时通过补水小孔,泄水腔、浮球阀出口断面的流量相等;连接进水腔和泄压腔的通道进口、泄压腔内和浮球阀出水口(控制管路)等断面用伯诺里方程可以得到C1的影响因素(断面位置如图3立式液压控制阀安装示意图所示),有各下列各式成立: ω通ν通=ω泄ν泄=ω球ν球 d12ν通=D12ν泄=d球2ν球……………………(3) Z进+P0/γ +α1ν通2/2g=Z泄+P1/γ +α2ν泄2/2g+h损1=Z球+P球/γ+α3ν球2/2g+h损2……………………(4) 整理上式,推导得: P1=C1=γ((Z球-Z泄)+P球/γ+(α3ν球2-α2ν泄2)/2g+(h损2-h损1)) =γ((Z球-Z泄)+P0/γ+(α3ν球2-α2ν泄2)/2g-h损3)……………………(5) ω及下标:表示水流对应断面的面积 ν及下标:表示水流对应断面的液体流速 Z及下标:表示水流对应断面的几何高程 P及下标:表示水流压力 γ:液体比重 α及下标:对应动能修整系数 h及下标:沿程及局部水头损失之和 g:重力加速度 3.3影响液压控制阀稳定运行的因素 3.3.1液压阀自身结构 液压阀要可靠运行,要求活塞式阀芯坚固,升降灵活,能始终保持泄压腔的密闭并能根据需要密闭进水腔;泄压腔与进水腔通道小孔畅通。依据水力学知识,从(5)式可以看出,连接泄压腔的小孔通道d1越小,水头损失h损3越大,则C1值降低。可见适当减小小孔通道直径d1有助于降低C1值,浮球阀开启时,阀芯能迅速上升,打开液压阀。浮球阀关闭时,由于补水能力减弱,泄压腔压力上升减慢,能够减小阀芯下降速度,可以减小(和避免)液压阀的关阀水锤,从而提高液压阀的性能。但是,小孔通道直径d1过小,容易造成孔道堵塞,致使液压阀开关不灵。另外,加大活塞式阀芯泄压腔端的直径,有助于降低泄压腔的关阀作用压力;但会增加对开阀压力P0的要求。 3.3.2液压阀的安装 液压阀的安装,应适当选择控制管的管径和长度。控制管径加大,水流速度将降低,通过控制管的水力损失h损4减少,C1值将减小,有利于液压阀的运行。控制管的管径一般在dn15~dn40之间,若控制管的管径过大,配套的浮球阀加大,一方面浮球将缩小水池的储水空间,降低水池空间的利用率;另一方面,浮球关闭时,泄压腔升压时间加长,液压阀将延时关闭,需要水池有较大的有效空间才能不浪费水资源。控制管的长度也应有所限制,增加控制管的长度,h损4增加,C1值增加,泄压腔升压时间加长,液压阀将延时关闭,不利与液压阀的稳定运行。 3.3.3进水压力及水流状态 液压阀在工作时,其作用力由进水压力P0引起,进水压力越低,提升阀芯要求泄压腔的P1也低,即C1值要小,不利于液压阀工作。当P0较低,泄压腔泄压后,活塞式阀芯受到向上的压力作用不能克服其自身重力和摩擦力时,液压阀将不能开启。由于受阀体各部件材料的限制,P0也不能太高。高压力使阀芯受到的作用力N1N2加大,对阀芯密封圈的磨损增强,影响液压阀的使用寿命。故液压阀必须工作在标称压力范围内。由于水流方向的改变,阀体内各部件均受到水流的激烈冲刷,撞击,必须采取措施,保证阀芯结构稳定,阀芯组成件(密封圈、导向脚、锁闭螺栓等)位置正确,不松动。 3.3.4水质情况 运行要求介质为洁净水,设计和安装均能做到使液压阀进水中不含固体颗粒,不堵塞阀体内部的大小通道,不腐蚀液压阀的内部结构。但水中溶解性固体栖出,在液压阀阀体内和控制管道内结垢,从而影响阀体的泄压腔的密封性,增大了阀芯摩擦力f,阀芯运动的作用力增加,同时控制管泄水断面减小,泄压腔的泄水能力减小,控制管的水头损失h损4增大,C1值增大,当C1值增大到某一程度,活塞式阀芯不能灵活运动,从而使液压阀失灵。对硬度高,溶解性固体较多的介质,需要适当加大控制管的管径并加强对液压控制阀的运行维护。 4、提高液压水位控制阀稳定运行的方案 4.1针对性选择液压阀的型号 应针对工作压力要求、介质温度、介质的物理化学性质等情况,选择规格型号材质匹配的液压控制阀。对水质硬度较高,容易结垢的地区,如贵州等喀斯特地貌地区,水中含有的碳酸氢盖在温度和水力作用下极易结垢,应选择d1较大的液压控制阀并适当加大控制管的管径。 4.2合理安装 选定液压水位阀控制阀的型号后,应根据产品特性合理安装。安装时的注意事项:选择与液压阀型号规格压力相匹配的连接法兰;进水管直径应大于或等于阀门公称通径,出水口应低于浮球阀。浮球阀安装应距离出水管口一米以上且应安装在利于检修的位置,比如水池的人孔附近;为防止水力松动阀芯结构,应对阀芯活塞杆两端紧固螺母采取防退措施。为防止虹吸倒流,水箱内出口管出水口应设置防虹吸小孔或略高于控制水位。为防止噪声及水位波动,出水口应设置消能筒。使用时,截止阀应全开,如同一水池安装二只以上阀则应保持同一水平面。因主阀关闭要滞后浮球阀关闭约30~50秒,故水箱要有足够的空余容积,以防溢水。为防止杂质、砂粒进入阀内引起工作失灵,阀前应装过滤器。如安装在地下室水池,则应在地下泵房安装报警装置。 4.3加强日常维护保养 在安装液压阀前,应注意将管道冲洗干净,液压阀在使用中,应视水质情况选择保养时间,一般一年保养一至二次,当水质清洁度较差时,需适当增加保养次数。具体保养方法如下: (1)关闭该阀前的闸阀。 (2)旋下阀盖上的螺栓。 (3)取出阀门内部活塞、活塞杆和导向盖等。 (4)旋下活塞杆两端螺母。 (5)拆下压盖、密封圈、阀瓣。 (6)拆下导向压盖、密封圈、阀瓣。 拆卸后,应除去各零件的水垢和各种污物,用钢丝疏通节流螺母上小孔,更换已损坏的密封件。装配顺序和拆卸顺序相反。 5、结论 有针对性的选择液压水位控制阀的型号,合理安装,加强液压水位控制阀的日常维护保养工作,提高液压水位控制阀的稳定性,避免液压水位控制阀失灵,使其能高效长期稳定运行,保证安全供水。

“ Improve the level of hydraulic control valves and stable operation of the I See”是由提供的国际阀门新闻,译文仅供参考。另外,中国控制阀网还提供相关产品搜索:、、、、等。


原文:
1 Introduction Hydraulic level control valve is an improved floating ball valve, when the water level inside the tank or water cooling towers fell, floating open the drain valve when the pressure inside the water inlet valve piston will hold up, sealing surface to open, the valve that is open water supply, when the water level rises to the control surface, floating ball valve closed, the piston sealing surface will be closed down, the valve to stop water supply, the water level so as to achieve the purpose of automatic control. Because no power can be, simple structure, easy installation and construction, the advantages of wide application of pressure, in various types of fresh water pond (tank) of water has a relatively wide range of automation applications. However, due to factors such as water quality and water effects, hydraulic level control valve is often failure, ranging from waste water, re-pumping stations were flooded, causing serious consequences. To improve the stability of hydraulic level control valve to ensure safe water supplies becomes essential. 2, hydraulic level control valve of the internal structure and function of Principle Hydraulic level control valves are generally float valve to control the pipe, hydraulic valve of the main component. Although the appearance of the main hydraulic control valves vary in different materials, there are forms of vertical and horizontal installation, but its internal structure and role of the principles are basically the same. The main hydraulic control valve from the inlet chamber, outlet, piston-type valve core, cavity pressure relief, pressure relief port etc., shown in Figure 1. Water-based water pressure for the P0, pressure relief chamber pressure P1; piston spool of gravity for the G, piston-type pressure relief cavity side of the spool diameter D1, the other end of the diameter of D2. Connectivity, water chamber and the pressure relief cavity hole diameter d1, the pressure relief port diameter d2, piston spool valve cavity and the friction force of f, subject to supportive for the N. Below in Figure 1 Schematic diagram of a (structure similar to 2) as an example, analysis of the force piston spool as follows: Set up a joint force by the piston spool of F, then the spool by the force vector equation is: F = F1 + F2 + F3 + F4 + f + N + G ... ... ... ... ... ... ... ... (1) Expressed as algebraic form as follows: F = P0D22π / 4 + P2 (D12π/4- D22π / 4) - P1D12π / 4 ± f-G ± N = (P0D22-P1D12) π / 4 ± f-G + P2 (D12-D22) π / 4 ± N = A ± f-G ± N + B ... ... ... ... ... ... ... ... (2) (2) where A = (P0D22-P1D12) π / 4, B = P2 (D12-D22) π / 4; f the symbols and the symbols A contrary. When the water level inside the tank or water cooling towers fell, floating ball valve to open drainage, the water chamber through the hole to the pressure relief chamber d1 pay, due to replenishment hole d1 0, the sealing surface has gradually opened up , the hydraulic valve that is open to the pool (or towers) water supply. When the pool water level rises to the control surface, floating ball valve closed, pressure relief chamber replenishment capacity is greater than the pressure relief capability, N2 gradually decreased, P1 increased (up to P0), the type F <0>700X pump control valve water level control valve diagram 3.2 The pressure relief cavity pressure changes Hydraulic control valves installed when put into use, (2) where D1, D2, d1, d2G known constant, the impact force piston spool movement only water pressure P0, P1 being the role and the piston friction f . Under normal circumstances: D1 ≥ D2, d1 ≤ d2, outlet pressure range of 0 ≤ P2 for clean water media, design and installation of hydraulic valves are able to do so does not contain solid particles in water, non-blocking valve the size of the internal channel, non-corrosive hydraulic valve of the internal structure. However, habitat out of the water soluble solids in the hydraulic valve and control valve body pipe scale, thus affecting the pressure relief valve cavity seal, increases the spool friction f, spool movement to increase the force, whilemovements so that the hydraulic valve failure. Pairs of high hardness, dissolved solids more media, the need for appropriate control of tube diameter to increase and strengthen the operation and maintenance of hydraulic control valves. 4, raising the water level control valve of hydraulic stable operation of the program 4.1 Select specific type of hydraulic valve Should be aimed at the working pressure requirements, medium temperature, media, physical and chemical properties, etc., choose the standard model of the hydraulic control valve material match. Higher hardness of water quality, easily scaling the regions such as Guizhou karst areas, water contains bicarbonate covered under the action of temperature and water can easily scale should be selected d1 larger increase of hydraulic control valves and appropriate control of tube diameter. 4.2 Installation and reasonable Selected level of hydraulic valve control valve model, it should be reasonable based on product features to install. Notes on installation: Select and hydraulic pressure valve model specifications to match the connection flange; into the pipe diameter should be greater than or equal to the nominal valve diameter, the outlet should be lower than floating ball valve. Floating ball valve installation should be more than one meter from the outlet pipe mouth and should be installed in the location conducive to maintenance, such as the pool of people near the hole; in order to prevent loosening hydraulic valve core structure, and response to both ends of spool rod nut to take anti-withdrawal measures. In order to prevent backflow siphon water tanks within the exit pipe outlet should be set up anti-siphon holes or slightly higher than control level. In order to prevent noise and water level fluctuations in the outlet tube should be set energy dissipation. Used, cut-off valve should be fully open, as a pool for more than two valves should be installed to maintain the same horizontal plane. Due to the main valve closure to lag float valve shut down about 30 ~ 50 seconds, so tanks have enough spare capacity to prevent overflow. In order to prevent contamination, caused by the work of sand into the valve failure, valve should be installed before the filter. If installed in the basement pool, it should be installed in the underground pumping station alarm device. 4.3 strengthen the routine maintenance The installation of hydraulic valves, should pay attention to clean the pipes, the hydraulic valve in use, should be chosen depending on the water quality maintenance time, the general maintenance once or twice a year, when the water cleanliness poor, the need to increase the maintenance of an appropriate number of times. Specific Maintenance is as follows: (1) close the valve before the valve. (2) The rotation of the bolt under the valve cover. (3) Remove the valve within the piston, piston rod and a guide cover. (4) spin at both ends under the rod nut. (5) removed the gland, seals, valve flap. (6) orientation gland removed, seals, valve flap. After the dismantling of all parts of the scale should be removed and all kinds of dirt, using wire nut on the throttle to clear the holes, replace damaged seals. Assembly and disassembly sequence in reverse order. 5, the conclusion Targeted selection of hydraulic level control valve model, and reasonable installation, hydraulic level control valve to enhance the daily maintenance work to improve the stability of hydraulic level control valve to prevent hydraulic failure of water level control valve to enable them to long-term stability and efficient operation, to ensure safe water supplies.


原文来源:

<#--{zx1}日志--> <#--推荐日志--> <#--引用记录--> <#--相关日志--> <#--推荐日志--> <#--右边模块结构--> <#--评论模块结构--> <#--引用模块结构-->
郑重声明:资讯 【提高液压水位控制阀稳定运行性之我见】由 发布,版权归原作者及其所在单位,其原创性以及文中陈述文字和内容未经(企业库qiyeku.com)证实,请读者仅作参考,并请自行核实相关内容。若本文有侵犯到您的版权, 请你提供相关证明及申请并与我们联系(qiyeku # qq.com)或【在线投诉】,我们审核后将会尽快处理。
—— 相关资讯 ——