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1、Torque overload protectionValve electric device is used to operate the valve and was one of the valves connected to the device. The device is driven by electricity, their motion process can be stroke, torque, or to control the size of the axial thrust. As the valve should be the work of electrical d
2、evice characteristics and utilization depend on the type of valves, fittings and valves regulate the work of the pipeline or equipment location. Therefore, control valve electric device the right choice; consider the prevention of overload (working torque higher than the control torque) has become e
3、ssential to the occurrence of a ring. Valve electric device right choice should be based on: 1. Operation torque: Operation torque is to select the main valve electrical device parameters. The output torque electric actuator valve operation should be the greatest moment of 1.2 1.5 times. 2. Operatio
4、n Thrust: the host structure ofMOTORIZED VALVE ACTUATOR the valve electric device, there are two, one is not configured thrust plate, this time directly to the output torque; the other is equipped with thrust plate, and this time the output torque of the valve stem through the thrust disk nut is con
5、verted to the output thrust. 3. Number of output shaft rotation circle: valve electric actuator output shaft rotation the number of laps and the valve nominal diameter, stem pitch, thread the first few related, according to M = H / ZS computing (where: M for the electrical installations should be to
6、 meet the total number of rotating ring; H of the valve opening height, mm; S to stem transmission thread pitch, mm; Z to stem the number of screw heads.) 4. Stem Diameter: For multi-turn type valves for the next shot, if the electric actuator allows the maximum stem diameter of the valve stem can n
7、ot be dispensed, it can not be assembled into electric valve. Therefore, the electrical device hollow output shaft diameter must be greater than specified under the valve stem diameter. For some rotary valves, as well as multi-turn valves in the dark bar valve, although without considering the adopt
8、ion of stem diameter, but should also take full account of the matching stem diameter and keyway size, so that work can be assembled . 5. Output Speed: valve Kai, closed fast, easy to produce water hammer phenomenon. Should therefore be under different conditions of use, choose the appropriate Kai a
9、nd closing speed. 6. The installation, connection method: electric equipment installation for vertical installation, the level of the installation, floor installation; connections as follows: Are thrust plate; stem through (Ming pole multi-turn valves); dark bar multi-turn; without thrust disk; stem
10、 is not passed; part of the rotation Electric device is widely used, is to achieveproduction program-controlled valves, automatic control and remote control can not be a lack of equipment, its main use in the closed valve. But we can not ignore the special requirements of valve electric device - mus
11、t be able to limit the torque or axial force. Valve Electric installations are usually limited torque Couplings. When the electrical device specification is determined, the control torque is also determined. While in a pre-determined period of time to run when the motor normally does not overload. H
12、owever, if the following conditions so that it can be overloaded: 1. Power supply voltage is low, are not required torque, the motor stops rotating. 2. Mistakenly set the torque limit adjustment agencies, so that it is greater than stop torque, generated too large a result of continuous torque, the
13、motor stops rotating. 3. Such as the point of action as intermittent use of heat generated savings of up, more than the allowable temperature rise of the motor. 4. Torque limit for some reason, institutional circuit failure, so that torque is too large. 5. Use of environmental temperature is too hig
14、h, relative to the heat capacity of the motor down. The above is the excessive number of reasons, for these reasons should be generated by motor overheating in advance, taking into account, and to take measures to prevent overheating. In the past to protect the motor way is to use fuses, overcurrent
15、 relays, thermal relays, thermostats, etc., but these approaches also have their pros and cons of this change for the electrical device load devices, is absolutely reliable protection method is not. Must therefore take all methods combined approach. However, as the load on each electrical device is
16、different, it is difficult to propose a unified approach. In most cases, but generally, you can also find common ground. Overload protection taken by the way, be grouped into two types: 1. Changes in input current to the motor to judge; 2. To judge the heat of the motor itself. These two methods, re
17、gardless of the kind production Summarize of motor thermal capacity must take into account the given time margin. If a single way that will make the heat capacity characteristics of the motor line is difficult. Therefore, over-load should be selected according to the reasons for the action can be a
18、reliable method - combination of complex ways in order to achieve a comprehensive over-load protection. Rotork electric actuator motor, its embedded in the windings in the motor insulation level consistent with the thermostat, when the reach the rated temperature, motor control loop will be cut off.
19、 Thermostat heat capacity is small in itself, and its time-limited features is the motor heat capacity characteristics of the decision, so this is a reliable method. The basic method of overload protection are: 1. Continuous operation of motor jog operation, or overload protection with a thermostat;
20、 2. Locked-rotor protection of motor thermal relay 3. Pairs of short circuit faults using fuse or overcurrent relays. Valve electric device to prevent overload of the right choice and is very much related and should pay attention to.In consideration of economic aspects limiting torques is a continuo
21、us challenge when developing Torque Limiters as an overload protection. The new generation of the backlash-free Torque Limiters. The new generation of the backlash-free Torque Limiters has been designed for being used in power-transmission and servo applications. Important requirements such as being
22、 backlash-free, short reaction times and long service life have been further optimized. The constructive benefit is ensured through fast availability of applications after a crash.For limited installationsThe further development and optimization of the already well established backlash-free Torque L
23、imiter series SK has brought about an appropriate design for each application. The transmittable torques can be accurate defined and set. Even in regard to restricted installation space now, the couplings represent the latest state-of-the-art.Areas of applications of the Torque Limiters ranging from
24、 0.1 to 2,800 Nm can be found in any type of mechanical engineering.Highly dynamic drives are being continously improved by the use of preset Torque Limiters. When the overload occurs the Torque Limiters disengage in milli seconds. The movement of the Actuation ring can be sensed, and used to contro
25、l and shut down the machine. Immediate availabillity of the machine after re-engagement of the Torque Limiter can be assured.Increased economic efficiencyOptimized disc springs and materials adapted to the use of the coupling allow for the compact and reliable design, better performance and wer mass
26、. Also a long service life and maintenance free operation are importtant consierations when selecting couplings.Smaller couplings combined with a higher torque density additionally result in a cost advantage due to smaller dimensioning.On average the size of the Torque Limiter has been reduced by ap
27、prox. 1/3 compared to other available products. This results in a reduced separation of masses in case of a crash due to the reduced weight and a smaller technical diameter.When comparing the facts, it is clear that R + W develops and delivers the most compact Torque Limiters available period.A grea
28、t variety The advantage of ball detent design Torque Limiters is the separation of the drive and the driven elements in milliseconds in case of an overload. Easy handling reliability are further advantages.Machine designs with little installation space or difficult to access areas do however often r
29、equire special solutions. The R+ W range facilitates the easy modification by means of a modular concept. The hub type that is appropriate for the application is selected and integrated for the ideal design.The press-fit principle that has been developed by R+W uses the axial spring force of the met
30、al bellows to pre-tension a tapered male part into the corresponding counter-piece slightly axially. An axial pre-tensioning of the metal bellows of only 0.2 millimeters assures the absolutely backlash-free torque transmission. The self-adjusting tapered segment guaranties a wear and maintenance-fre
31、e operation.Torque limiters with damping PropertiesR+W has designed and launched a new overload protection with damping Properties. This combines the known elastomer couplings with a torque limiting portion.Between the safety element with clamping hub and the other coupling half, there is an elastom
32、er insert made of thermoplastic polyurethane (TPU) absorbing the drive vibrations. Owing to its elasticity, it is able to compensate axial, angular and lateral misalignment, vibrations, and impacts. During operation in machines with frequent impact, change or vibration load, its high damping capacit
33、y can have a positive effect on the service life of the connected aggregates. This however only applies to first-quality couplings which consist of individual elements showing the necessary truth of running and concentricity of the bores.Poor manufactured couplings may cause pulsating radial forces
34、onto the rotational axle during operation.Choice of different Shore hardnessThere is a choice of elastomer inserts with different Shore hardness 98 A, 64 D, and 80 A. The inserts are calibrated most precisely in order to ensure perfect mounting of the coupling. The otherwise usual, but high pretensi
35、on of the inserts is thus reduced and the assembly is much easier. If on the other hand the inserts are pressed in at too high pretension, the radial forces occurring with lateral misalignment on the shafts will increase. In addition, there is the risk of too much inner heating of the inserts becaus
36、e of increased flexing work.Made of special steel, even completely sealedFor applications in the food area it is mostly required to oftect the coupling against aggressive cleaning detergents , liquid media, or dirt. Sealed couplings are also used in clean-room technology and in very dusty applicatio
37、ns. A complete sealing that is optionally offered by R+W avoids leaking grease and at the same time penetration of coupling damaging substances. This solution ofvides all the sealing elements integrated in one component. An O-ring is inserted in the base element of the coupling and covered by an ext
38、ended Actuation ring. This system makes sure that the external dimensions of the coupling stay the same. Costly solutions where the coupling was sealed with a housing are therefore unnecessaryThe complete programm is additionally offered in stainless steel version. Nitrocarburizing, oxidizing, or ni
39、ckel-plating is possible for steel types. Aluminum can be anodized, other materials and surfaces can be offered on request.Function of the patented R+W prinzipleR+Ws patented operational principle guarantees reliable and safe protection against overload even with heavy loads. Due to the spring loade
40、d ball detent design of the coupling high repeating accuracy of the preset disengagement torque is reached and continuous operation is ensured when using a ball detent design Torque Limiter vs. a slip clutch. Overload protection does not allow any comofmises in regard to reliability and quality of t
41、he individual components although Torque Limiters are always designed for an economic use. R + W conceived a solution which stands out.Function always assuredAt the factory the Torque Limiters are adjusted to the exact disengagement torque requested by the customer. After installation the disengagem
42、ent value can easily be changed to siut actual requirements.The torque adjustment range is engraved on the adjustment nut. An outstanding feature opf the R+W design is an easy radial adjustment which clearly facilitates adjustment of the coupling. Due to the positive stop on the adjustment nut, dise
43、ngagement of the coupling is allways assured.For each coupling model there are four different function systems available:single position = attempting re-engagement automatically in the same position (360)multi-position = attempting re-engagement in several positions per revolutionfull disengagement
44、= complete load separation, must be re-engaged manuallyload holding = no disengagement occurs but an external sensor can be instantly triggered.With these four function systems R+W offers a solution for every application.ConclusionMost importantly in mass production situations, machine down time cau
45、ses high loss of Production which inevitably results in rising unit costs. When using a Torque Limiter, which separates driving force and driven force in milliseconds and is thus fully operable after a very short period of time, consequential damages will be minimized. The price of the coupling can
46、be considered as being relatively very low when compared to the cost of down time.扭矩过载保护器阀门电动装置是用于操作阀门并于阀门相连接的装置之一。该装置由电力来驱动,其运动过程可由行程、转矩或轴向推力的大小来控制。由于阀门电动装置应有的工作特性和利用率取决于阀门的种类、装置的工作规范及阀门在管线或设备上的位置。因此掌握阀门电动装置正确的选择;考虑防止超负荷(工作转矩高于控制转矩)的发生就成为至关重要的一环。阀门电动装置的正确选择应依据: 1操作力矩:操作力矩是选择阀门电动装置的最主要的参数。电动装置的输出力矩应
47、为阀门操作最大力矩的1.21.5倍。 2操作推力:阀门电动装置的主机结构有两种,一种是不配置推力盘的,此时直接输出力矩;另一种是配置有推力盘的,此时输出力矩通过推力盘中的阀杆螺母转换为输出推力。 3输出轴转动圈数:阀门电动装置输出轴转动圈数的多少与阀门的公称通径、阀杆螺距、螺纹头数有关,按M=H/ZS计算(式中:M为电动装置应满足的总转动圈数;H为阀门的开启高度,mm;S为阀杆传动螺纹的螺距,mm;Z为阀杆螺纹头数。) 4阀杆直径:对于多回转类的明杆阀门来说,如果电动装置允许通过的最大阀杆直径不能通过所配阀门的阀杆,便不能组装成电动阀门。因此,电动装置空心输出轴的内径必须大于明杆阀门的阀杆外径
48、。对于部分回转阀门以及多回转阀门中的暗杆阀门,虽不用考虑阀杆直径的通过问题,但在选配时亦应充分考虑阀杆直径与键槽的尺寸,使组装后能正常工作。 5输出转速:阀门的启、闭速度快,易产生水击现象。因此,应根据不同的使用条件,选择恰当的启、闭速度。 6安装、连接方式:电动装置的安装方式有垂直安装、水平安装、落地安装;连接方式为: 有推力盘;阀杆通过(明杆多回转阀门);暗杆多回转;无推力盘;阀杆不通过;部分回转 电动装置的用途很广,是实现阀门程控、自控和遥控不可缺少的设备,其主要用在闭路阀门上。但不能忽视阀门电动装置的特殊要求必须能够限定转矩或轴向力。通常阀门电动装置采用限制转矩的连轴器。 当电动装置的
49、规格确定之后,其控制转矩也确定了。当其在预先确定的时间内运行时,电机一般不会超负荷。但如出现下列情况便可使其超负荷: 1电源电压低,得不到所需的转矩,使电机停止转动。 2错误地调定了转矩限制机构,使其大于停止的转矩,而造成连续产生过大的转矩,使电机停止转动。 3如点动那样断续使用,产生的热量积蓄起来,超过了电机的容许温升值。 4因某种原因转矩限制机构电路发生故障,使转矩过大。 5使用环境温度过高,相对地使电机的热容量下降。 以上是出现超负荷的一些原因,对于这些原因产生的电机过热现象应预先考虑到,并采取措施,防止过热。 过去对电机进行保护的办法是使用熔断器、过流继电器、热继电器、恒温器等,但这些办法也都各有利弊,对于电动装置这种变负荷的设备,绝对可靠的保护办法是没有的。因此必须采取各种方法组合的方式。但由于每台电动装置的负荷情况不同,难以提出一个统一的办法。但概括多数情况,也可以从中找到共同点。采取的过负荷保护方式,归纳为两种: 1对电机输入电流的增减进行判断; 2对电机本身发热进行判断。 上述两种方式,无论那种都要考虑电机热容量给定
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