原文:
VPR气动阀门定位器(简称VPR定位器)是日本山武——霍尼韦尔公司VFR凸轮挠曲调节阀的专用附件。它按照气动调节器的信号,使调节阀正确快速动作,从而xx调节阀门流量及保证流量特性。我厂于八十年代中期引进生产,目前已广泛应用于石化、电力、轻工与化工等行业的自控系统中。
为了正确使用与维修,需要说明其工作原理,见图1。输入信号增加后,波纹管膨胀来推动挡板(即杠杆)靠近喷嘴端面。间隙减小则喷嘴背压升高,通过继动器膜片推动阀芯下移。进气口开大排气口关小使输出压力增加,因此执行机构推杆向下移动使调节阀阀芯开启或关闭。随着阀芯转动,凸轮也转动,通过凸轮随动件拉动反馈弹簧,使挡板趋于离开喷嘴,直到波纹管产生的力矩与反馈弹簧力矩相互平衡。由于这种力矩平衡,保证了调节阀开度与输入信号之间对应关系准确,实现了阀芯正确定位。
以下分析常见故障原因及措施。简单的排除措施将省略说明。
故障一:定位器无输出压力
1.无信号压力,①气动调节器故障;②信号管线大量漏气。
2.波纹管大量漏气,补焊锡或更换。
3.无供气压力或者供气压力过低。
4.波纹管节流孔堵塞,使用直径小于囝0.2mm的金属丝进行疏通。
5.定位器零点位置调节不妥,即挡板与喷嘴间隙太大。使用工具重新调节。
6.凸轮安装位置错误。因为一个凸轮分别包含气开式与气关式等百分比,气开式与气关式线性特性,有四个安装孔,容易装错。
7.挡板与喷嘴端面不垂直,挡板与喷嘴端面接触后仍然大量排气。
8.喷嘴孔端面有凹坑,需要更换。端面有毛刺,重新研磨。
9.喷嘴与基座粘接处漏气。
故障二:信号减小,输出压力不降低
1.零点位置调节不合适,即喷嘴挡板间隙太小。
2.继动器隔板处节流管孔径太小或者堵塞,使用Φ0.3mm金属丝进行疏通。
3.旁路机构开关位置错误,开关应位于“0N”位置。
4.偏差弹簧太硬或者选择错误,供气压力0.22MPa的簧丝直径为1.3mm,0.28~0.5MPa时簧丝直径为Φ1.4mm。
5.凸轮安装位置错误。
故障三:有供气、无信号、调节阀已完成大部分行程
1.继动器阀座与阀芯的SR2.3球面脱离接触或者密封不好。
2.在初始位置,挡板与喷嘴端面已经紧密接触。
故障四:基本误差(线性)不合格
1.反馈弹簧力或调零弹簧力调节不妥。
2.凸轮安装位置错误或行程指针装错。
3.继动器阀芯与动阀座凡尔线未密封。
4.波纹管刚度太低,设计要求4.9N/mm。
5.输出管线或执行机构漏气。
6.调节阀填料压缩量太大。
故障五:调节阀初始点误差大
1.凸轮随动件的轴套与凸轮未接触。
2.反馈弹簧选择错误,标准行程的簧丝直径为Φ0.8mm,分程信号为Φ0.7mm。
故障六:定位器回差(变差)不合格
1.零点位置或行程调节不妥。
2.转臂组件的紧固件松动。
3.零点位置调节后未拧紧锁紧螺钉。
4.波纹管弹性差,正反行程的位移量有微小差异。
5.凸轮随动件的轴套孔与外圆同轴度超出设计要求。
6.继动器偏差弹簧两端面平行度差。
7.转轴与轴瓦径向或轴向间隙太大。
8.供气压力不稳定。
9.轴套与凸轮轴径向或轴向间隙大。
10.反馈弹簧未经过立定处理。
“ VPR pneumatic valve positioner fault repair ”是由提供的阀门行业新闻,译文仅供参考。另外,中国气动阀门网还提供相关产品搜索:
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译文:
VPR pneumatic valve positioner (the VPR Locator) is Yamatake - Honeywell VFR Cam flexure control valve of the special annex. It pneumatic regulator according to the signal, so that quick action right valve, the valve to accurately adjust the flow and ensure the flow characteristics. I plant in the mid-eighties the introduction of the production, has been widely used in petrochemical, power, light industry and chemical industry in the automatic control system.
For proper use and maintenance, a description of how it works, see Figure 1. Input signal increases, expansion bellows to push the bezel (the lever) near the nozzle end. Gap reduces the nozzle back pressure, diaphragm actuators push through following the spool down. Large intake vents open so that the output pressure off small increase, thus putting downward movement so that implementing agencies spool valve to open or close. With the spool rotation, the cam also rotates with the moving parts driven by cam feedback spring, so that the faceplate tends to leave the nozzle until the bellows and feedback spring torque generated by torque balance each other. Because of this torque balance, ensure the valve opening and accurate correspondence between the input signal to achieve the correct positioning of the spool.
The following analysis of common cause of the malfunction and measures. Simple explanation for excluding measures will be omitted.
Fault 1: No output pressure Locator
1. No signal pressure, ① pneumatic regulator failure; ② large pipeline leak signal.
2. Bellows a large number of leaks, fill solder or replace.
3. No air pressure or air pressure too low.
4. Bellows orifice plug, use a diameter less than 0.2mm of the child to clear the wire.
5. Locator zero position adjustment is wrong, that baffle and the nozzle clearance too. Use the tool to re-adjust.
6. Cam install location wrong. Because a cam were open and the gas containing gas such as percentage of the relevant type, gas type and gas-related open-type linear characteristic, there are four mounting holes, easy to install wrong.
7. Does not end with the nozzle vertical baffle, baffle and nozzle face contact is still a lot of exhaust.
8. Nozzle hole face a pit, to be replaced. Face a burr, re-grinding.
9. Bond with the leaking of the nozzle base.
Fault 2: signal decreases, the output pressure without reducing
1. Zero position adjustment inappropriate, or nozzle flapper gap is too small.
2. Following the throttle actuator diaphragm aperture size is too small or office block, use Φ0.3mm wire to clear.
3. Body position error bypass switch, the switch should be in the "0N" position.
4. Bias spring is too hard or the wrong choice, gas pressure of 0.22MPa in the spring wire diameter of 1.3mm, 0.28 ~ 0.5MPa when the spring wire diameter Φ1.4mm.
5. Cam install location wrong.
Fault 3: with gas, no signal, control valve has completed most of the journey
1. Following the valve seat
and valve actuators of SR2.3 spherical seal disengagement or bad.
2. In the initial position, baffles have been in close contact with the nozzle end.
Failure 4: Basic error (linear) failure
1. Feedback spring force or spring force zero adjustment inappropriate.
2. Cam installation location error or equipment fault trip indicator.
3. Following the valve actuator and valve seat where fixed line is not sealed Seoul.
4. Bellows stiffness is too low, the design requirements 4.9N/mm.
5. Export pipeline leak or implementing agencies.
6. Valve packing too much compression.
Failure five: the initial error of the large valve
1. Cam follower and cam sleeve parts is not engagement.
2. Feedback spring selection error, the standard itinerary of spring wire diameter Φ0.8mm, sub-way signal Φ0.7mm.
Fault 6: Locator Backlash (worse) failure
1. Zero position or stroke adjustment inappropriate.
2. Transfer arm assembly of fastener loosening.
3. After the zero position adjustment locking screws did not tighten.
4. Flexible bellows poor displacement of positive and negative travel slightly different.
5. Cam follower with cylindrical pieces of coaxial shaft bush beyond the design requirements.
6. Following the bias spring actuator parallel to the surface at both ends of Difference.
7. Radial or axial shaft and the bearing clearance too.
8. Gas pressure instability.
9. Sleeve and the camshaft radial or axial gap large.
10. Feedback spring not been standing treatment.
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