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1、气动技术双语教程气动技术双语教程ContentslOperatorslFunctionlValve SizelActuator ControllTypical ValvelPoppet ValveslSpool ValveslDisc SealslDynamic SealslGlandless SpoollBalanced SpoollSpool Overlapl5/3 Valves lOther Valve Designs lPressure SwitcheslLogic ValveslFlow Regulators lQuick Exhaust valvelValve FlowlSolen
2、oid ValveslStatic SealingClick the section to advance directly to itlIntroduction气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5IntroductionnThe range of pneumatic valves is vast nTo help select a valve they are placed in a variety of categories: nstylentypendesign principlentype of operatornfunctionnsizenapp
3、lication nFor all of them, their basic function is to switch air flownFrom the simplest function of switching a single flow path on and off, to the exacting proportional control of pressure and flow气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5StylenStyle reflects the look of a valve range as well as the und
4、erlying design principle. Examples are Nugget, ISO Star and Super X气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5TypenType refers to the valves installation arrangement for example sub-base, manifold, in line, and valve island气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5DesignnDesign refers to the principle of opera
5、tion around which the valve has been designed, for example, spool valve, poppet valve and plate valve气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5OperatorsnAn operator is the mechanism that causes a valve to change statenThey are classified as manual, mechanical and electricalTwistPushButtonShroudedButtonMu
6、shroomButtonKeyOperatedSwitchKeyReleasedSolenoidPilotRollerOne WayTipAir PilotPlungerEmergencyStop气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve FunctionnFunction is the switching complexity of a valve nShown by two figures 2/2, 3/2, 4/2, 5/2, 3/3, 4/3 & 5/3nFirst figure is the number of main ports. Inl
7、ets, outlets, and exhausts excluding signal and external pilot suppliesnSecond figure is the number of states nA 3/2 valve has 3 ports, and 2 states, normal and operated.气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve SizenSize refers to a valves port thread. nFor similarly designed valves the amount of
8、air flow through the valve usually increases with the port size. nPort size alone however cannot be relied upon to give a standard value of flow as this is dependent on the design of the valve internals. nThe port size progression M5, R1/8 , R1/4, R3/8 , R1/2, R3/4, R1.M5R1/8R1/4R3/8R1/2R3/4R1气动技术双语
9、电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5ApplicationnApplication is a category for valves described by their function or task nExamples of specialist valves are quick exhaust valve, soft start valve and monitored dump valve nExamples of standard valves are power valves, logic valves, signal processing valves
10、and fail safe valves nA standard valve could be in any category depending on the function it has been selected for in a system气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Actuator Control (3/2 valve) nA 3 port valve provides the inlet, outlet and exhaust path and is the normal choice for control of a single
11、 acting cylindernIn the normal position produced by the spring, the valve is closednIn the operated position produced by the push button the valve is opennThe push button must be held down for as long as the cylinder is outstroked1231210气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Actuator Control (3/2 valv
12、e)nA 3 port valve provides the inlet, outlet and exhaust path and is the normal choice for control of a single acting cylindernIn the normal position produced by the spring, the valve is closednIn the operated position produced by the push button the valve is opennThe push button must be held down f
13、or as long as the cylinder is outstroked1210123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Actuator Control (5/2 valve)nA five port valve provides an inlet port 1 that is switched between two outlet ports 2 and 4 each with an exhaust port 3 & 5nIn the normal position produced by the spring 1 is connected t
14、o 2 with 4 to exhaust 5nIn the operated position produced by pushing the button port 1 is connected to 4 with 2 to exhaust 3153121442气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Actuator Control (5/2 valve)nA five port valve provides an inlet port 1 that is switched between two outlet ports 2 and 4 each wit
15、h an exhaust port 3 & 5nIn the normal position produced by the spring 1 is connected to 2 with 4 to exhaust 5nIn the operated position produced by pushing the button port 1 is connected to 4 with 2 to exhaust 3121415342气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5 nIdentification of the component parts of a
16、 typical 5/2 solenoid valve with spring return (Sub-base not shown)n(1) Solenoid (15mm)n(2) Pistonn(3) Spool with disc sealsn(4) Valve body n(5) Return springn(6) Alternative ports 2, 4n(7) Pressure indicatorn(8) Manual overriden(9) Electric connectors345678219Typical Valve气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪
17、明 Chapter 5Poppet Valves气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Poppet Valve 2/2nThe Poppet valve is a simple and effective design used mainly in 2/2 and 3/2 functionsn It has good sealing characteristics and can often be the choice for a supply shut off valvenA poppet seal has a butt action against a
18、raised edged aperture nIllustrated is a 2/2 air operated poppet valve1212气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Poppet Valve 2/2nThe Poppet valve is a simple and effective design used mainly in 2/2 and 3/2 functionsn It has good sealing characteristics and can often be the choice for a supply shut off
19、 valvenA poppet seal has a butt action against a raised edged aperture nIllustrated is a 2/2 air operated poppet valve1212气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Poppet Valve 3/2nMiniature 3/2 valve used for generating signals nThe poppet seal will give long life (not subjected to sliding friction)nSup
20、ply to port 1 assists the spring to hold the poppet shut nOutlet port 2 is connected through the plunger to a plain exhaust portnWhen operated exhaust path sealed and poppet opened (flow 1 to 2)123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Poppet Valve 3/2nMiniature 3/2 valve used for generating signals n
21、The poppet seal will give long life (not subjected to sliding friction)nSupply to port 1 assists the spring to hold the poppet shut nOutlet port 2 is connected through the plunger to a plain exhaust portnWhen operated exhaust path sealed and poppet opened (flow 1 to 2)123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明
22、Chapter 5Poppet Valve 3/2nMiniature 3/2 valve used for generating signals nThe poppet seal will give long life (not subjected to sliding friction)nSupply to port 1 assists the spring to hold the poppet shut nOutlet port 2 is connected through the plunger to a plain exhaust portnWhen operated exhaust
23、 path sealed and poppet opened (flow 1 to 2)123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool ValvesnA long standing popular versatile design nAvailable in most functions 3/2, 3/3, 5/2, 5/3, etc.nFully force balancednWide range of styles, sizes, operators and mounting arrangementsnSuit a multiple range
24、of applications 气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool TypesnA spool has a number of major and minor diameters called lands and valleys nThe lands seal with the valve bore and the valleys connect valve ports to control flow directionnDynamic seal type has the seals on the spoolnGlandless type ha
25、ve no sliding sealsnStatic seal type has the seals fixed in the valve bore气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Disc SealsnA disc seal is a loose fit in the groove, with the outer diameter just in contact with the valve bore. nUnder differential pressure the disc seal is pushed sideways and outwards
26、to seal the clearance between the outer diameter of the piston and the valve borenThe slim profile gives low radial force therefore reducing friction气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (dynamic seals)nThis 5/2 valve has a spool fitted with disc sealsnThe seals move with the spool theref
27、ore they are called dynamicnNormal position: port 1 is joined to 4 and 2 is joined to 3nOperated position: port 1 is joined to 2 and 4 is joined to 5142351245314121412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (dynamic seals)nThis 5/2 valve has a spool fitted with disc sealsnThe seals move wit
28、h the spool therefore they are called dynamicnNormal position: port 1 is joined to 4 and 2 is joined to 3nOperated position: port 1 is joined to 2 and 4 is joined to 5142351245314121412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (glandless)nThis 5/2 valve has a matched spool and sleeve. The fit
29、 is so precise that seals between them are unnecessarynThe tiny amount of air crossing the spool lands provides an air bearingnThe result is low friction and long life142351412124531412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (glandless)nThis 5/2 valve has a matched spool and sleeve. The fit
30、 is so precise that seals between them are unnecessarynThe tiny amount of air crossing the spool lands provides an air bearingnThe result is low friction and long life124531412142351412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (static seals)nThis 3/2 valve has a plain spool sliding within sta
31、tic sealsnThe O Ring seals are held in carriers fixed in the valve bore and positioned by spacers (not shown)nThe larger O Rings seal the valve bore with the carriersnThe smaller O Rings seal the carriers with the spool 12310121231210气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (static seals)nTh
32、is 3/2 valve has a plain spool sliding within static sealsnThe O Ring seals are held in carriers fixed in the valve bore and positioned by spacers (not shown)nThe larger O Rings seal the valve bore with the carriersnThe smaller O Rings seal the carriers with the spool 12310121231210气动技术双语电子教案气动技术双语电
33、子教案 吴洪明吴洪明 Chapter 5Spool Valve (static seals)nThis 5/2 valve has a plain spool sliding within static sealsnThe O Ring seals are held in carriers fixed in the valve bore and positioned by spacers (not shown)nThe larger O Rings seal the valve bore with the carriersnThe smaller O Rings seal the carrie
34、rs with the spool124531412453141212气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Spool Valve (static seals)nThis 5/2 valve has a plain spool sliding within static sealsnThe O Ring seals are held in carriers fixed in the valve bore and positioned by spacers (not shown)nThe larger O Rings seal the valve bore w
35、ith the carriersnThe smaller O Rings seal the carriers with the spool124531412124531412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Balanced SpoolnThe pressure acting at any port will not cause the spool to movenThe areas to the left and right are equal and will produce equal and opposite forces nBalanced s
36、pool valves have a wide range of application as any selection of pressures can be applied to the 5 ports. Single pressure and twin pressure supply versions shown 142351412141214235气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5OverlapnMost spool valves are designed with a positive overlapnWhen the spool is in
37、 transit from the normal to the operated state port 2 will be closed before port 4 is opened (or 4 before 2)nIf the spool is being moved slowly a negative overlap will cause pressure loss during the spool changeover and may even stall142351412142351412PositiveoverlapNegativeoverlap气动技术双语电子教案气动技术双语电子
38、教案 吴洪明吴洪明 Chapter 5Three Position Spool ValvesnThis type of valve has a normal state where the spool is in a mid positionnThe characteristic in the centre position is determined by the land spacings on the spoolnThe three types are:All ports blockedOpen exhaustsOpen pressure241531245312453气动技术双语电子教案
39、气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve Spools (dynamic seals)All ports blocked 5/3Open to exhaust 5/3Open to pressure 5/3Standard 5/2 spoolIdentification groovesExamples from the Nugget 120 range气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (all ports sealed)nWith the spool in the mid (normal) position a
40、ll ports are sealednSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1 is joined to 2, port 4 is joined to 514235141212453气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (all ports sealed)nWith the spool in the mid (normal) position all ports are sealednSpool right, port 1 i
41、s joined to 4, port 2 is joined to 3nSpool left, port 1 is joined to 2, port 4 is joined to 514235141212453气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (all ports sealed)nWith the spool in the mid (normal) position all ports are sealednSpool right, port 1 is joined to 4, port 2 is joined to 3nSpoo
42、l left, port 1 is joined to 2, port 4 is joined to 514235141212453气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open exhausts)nWith the spool in the mid (normal) position the supply port is sealed and outlet ports are to exhaustnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left,
43、 port 1 is joined to 2, port 4 is joined to 512453142351412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open exhausts)nWith the spool in the mid (normal) position the supply port is sealed and outlet ports are to exhaustnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1
44、 is joined to 2, port 4 is joined to 512453142351412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open exhausts)nWith the spool in the mid (normal) position the supply port is sealed and outlet ports are to exhaustnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1 is joi
45、ned to 2, port 4 is joined to 512453142351412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open pressure)nWith the spool in the mid (normal) position the supply port is connected to both outlet portsnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1 is joined to 2, port
46、4 is joined to 514235141212453气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open pressure)nWith the spool in the mid (normal) position the supply port is connected to both outlet portsnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1 is joined to 2, port 4 is joined to
47、514235141231245气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 55/3 Valve (open pressure)nWith the spool in the mid (normal) position the supply port is connected to both outlet portsnSpool right, port 1 is joined to 4, port 2 is joined to 3nSpool left, port 1 is joined to 2, port 4 is joined to 514235141212453
48、气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Other Valve Designs气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Bleed ValvesnProvide valve operation from a low operating forcenIn the normal position the lever arm is holding the bleed orifice closednThe differential piston has supply pressure acting on the small end, a
49、lso the large end through a restrictor in the pistonnA light operating force will lift the bleed seal allowing air to escapenFlow through the piston is slower than the bleed orifice so the pressure is lost and the piston changes statenReleasing the lever causes the piston to reset1232121013气动技术双语电子教
50、案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Bleed ValvesnProvide valve operation from a low operating forcenIn the normal position the lever arm is holding the bleed orifice closednThe differential piston has supply pressure acting on the small end, also the large end through a restrictor in the pistonnA light oper
51、ating force will lift the bleed seal allowing air to escapenFlow through the piston is slower than the bleed orifice so the pressure is lost and the piston changes statenReleasing the lever causes the piston to reset1232121013气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Plate ValvesnHave no sliding syntheti
52、c rubber sealsnThe rotary slide (red) is ground flat with the basenPressure supplied at port 1 pushes the plate down to seal, also supplies outlet port 2nThe cavity in the plate connects outlet port 4 to exhaust port 3nWhen operated the plate swings to connect port 2 to exhaust 3 and 1 to 41234nVers
53、ions 4/2 and 4/3 with detented centre positionnPart movement of lever will give flow control24124313气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Plate ValvesnHave no sliding synthetic rubber sealsnThe rotary slide (red) is ground flat with the basenPressure supplied at port 1 pushes the plate down to seal,
54、also supplies outlet port 2nThe cavity in the plate connects outlet port 4 to exhaust port 3nWhen operated the plate swings to connect port 2 to exhaust 3 and 1 to 41234nVersions 4/2 and 4/3 with detented centre positionnPart movement of lever will give flow control24124313气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪
55、明 Chapter 5Pressure Switch (pneumatic)nRelay to boost weak signalsnRelay for a pneumatic time delaynWhen the signal at port 12 reaches about 50% of the supply pressure at port 1, the pressure switch operates to give a strong output signal at 2nFor time delays at any pressure only the linear part of
56、the curve will be used giving smooth adjustment13121012312101231210气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Pressure SwitchesnPressure applied at port 1 acting on the differential annular areas holds the spool to the leftnThe weak or slowly rising pressure of a signal applied to port 12 needs only to re
57、ach about 50% of he pressure at port 1 to operate the valvenPort 1 is then connected to port 2nRemoving the signal allows the differential force to reset the valve123121231210气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Pressure SwitchesnPressure applied at port 1 acting on the differential annular areas ho
58、lds the spool to the leftnThe weak or slowly rising pressure of a signal applied to port 12 needs only to reach about 50% of he pressure at port 1 to operate the valvenPort 1 is then connected to port 2nRemoving the signal allows the differential force to reset the valve123121231210气动技术双语电子教案气动技术双语电
59、子教案 吴洪明吴洪明 Chapter 5Pressure Switches (electrical)nThis fixed value example uses a built in single acting cylinder to operate a standard changeover microswitchnThe operating pressure is about 3 bar this needs to overcome the combined force of the cylinder and microswitch springsnAdjustable pressure
60、switches are also availableFixedAdjustable气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Logic “OR” Shuttle ValvenAn air signal given to either the left hand port 1 or the right hand port 1 will result in an output at port 2nThe sealing disc moves across to seal the exhaust signal line to prevent loss of sign
61、al pressure 121121112气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Logic “AND” Shuttle ValvenA single air signal at either of the ports 1 will cause the shuttle to move and block the signalnIf a signals are applied at both the left hand AND right hand ports 1 only one of them will be blocked the other will b
62、e given as an output at port 2nIf the pressures are not equal the one with the lowest pressure is switched 112112112112112Popular oldsymbol112ISO 1219-1symbol气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Flow RegulationnBy the use of flow regulators the outstroke speed and instroke speed of a piston rod can
63、be independently adjustednSpeed is regulated by controlling the flow of air to exhaustnThe front port regulator controls the outstroke speed and the rear port regulator controls the instroke speed气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Flow RegulatornUni-directional, line mounted adjustable flow regula
64、tor nFree flow in one directionnAdjustable restricted flow in the other direction气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Flow RegulatornUni-directional, line mounted adjustable flow regulator nFree flow in one directionnAdjustable restricted flow in the other direction气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapte
65、r 5Banjo Flow RegulatornDesigned to fit directly in to cylinder ports, so placing adjustment at the appropriate cylinder end nTwo types: nOne to give conventional flow restriction out of the cylinder and free flow in (as illustrated)nThe other type to give restricted flow in to the cylinder and free
66、 flow out (not illustrated)气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Quick Exhaust ValvenIn some applications cylinder speed can be increased by 50% when using a quick exhaust valvenWhen operated, air from the front of the cylinder exhausts directly through the quick exhaust valvenThe faster exhaust give
67、s a lower back pressure in the cylinder therefore a higher pressure differential to drive out the piston rod气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Quick Exhaust ValvenPort 2 is connected directly to the end cover of a cylindernPort 1 receives air from the control valvenAir flows past the lips of the s
68、eal to drive the cylindernWhen the control valve is exhausted, the seal flips to the right opening the large direct flow pathnAir is exhausted very rapidly from the cylinder for increased speed1 2 12气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Quick Exhaust ValvenPort 2 is connected directly to the end cove
69、r of a cylindernPort 1 receives air from the control valvenAir flows past the lips of the seal to drive the cylindernWhen the control valve is exhausted, the seal flips to the right opening the large direct flow pathnAir is exhausted very rapidly from the cylinder for increased speed1 2 12气动技术双语电子教案
70、气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve Flow气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Flow through valvesnValve flow performance is usually indicated by a flow factor of some kind, such as “C”, “b”, “Cv”, “Kv”. Also orifice sizes “A” and “S” or by flow values I/min. and m3/h.nTesting a valve to ISO 6358, result
71、s in performance values of “C” (conductance) and “b” (critical pressure ratio) nFor a range of steady sourcepressures P1 the pressureP2 is plotted against varying flow through the valve untilit reaches a maximumnThe result is a set of curvesshowing the flow characteristicsof the valveP1P2气动技术双语电子教案气
72、动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve FlownFrom these curves the critical pressure ratio “b” can be found. “b” represents the ratio of P2 to P1 at which the flow velocity goes sonic. Also the conductance “C”at this point which represents the flow “dm/ second / bar absolute” Downstream Pressure P2 bar gaug
73、eCritical pressure ratio b = 0.150123456700.10.20.30.40.5ConductanceC= 0.062 dm/s/bar aFor the horizontal partof the curve onlyFlowdm3/sfreeairP1 is the zeroflow point for each curve气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve FlownIf a set of curves are not available but the conductance and critical
74、pressure ratio are known the value of flow for any pressure drop can be calculated using this formulaeQ = C P11 -1 - bP2P1- b2Where : P1 = upstream pressure bar aP2 = downstream pressure bar aC = conductance dm3/s/bar ab = critical pressure ratioQ = flow dm3/s气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Exa
75、mple calculationnCalculation of flow through a Nugget 120 valve supplied with 8 bar. A pressure drop of 1.5 bar is acceptable. The conductance and critical pressure ratios for the valve are C = 4.92 and b = 0.23 Q = 4.92 . (8+1)1 -1 - 0.232(6.5+1)(8+1)- 0.23Q = 27.45 l/s or 1647 l/min气动技术双语电子教案气动技术双
76、语电子教案 吴洪明吴洪明 Chapter 5Guide to Valve Size and FlownThis graph gives a guide to the to flow range appropriate to different valve sizesnPort size alone can only be a rough guide, individual valve types will vary according to designnThe flow values indicated by the vertical lines are at P1 = 6 bar, wit
77、h 1bar pressure dropValve sizeR1R3/4R1/2R3/8R1/4R1/8M5100006000425025001250750250Flow l/min气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Pressures and TemperaturesnThe working pressures for valves generally can range from vacuum to 16 barnThe majority of applications work at up to 10 barnSolenoid pilot opera
78、ted valves with integral supplies can work down to about 1.5 bar. Below this external pilot supplies are requirednOperating temperature is usually controlled by the limits of the seal materialnThe standard range is from 5 to 80OC ambientnFor solenoids due to heat generation 5 to 50OCnFor special low
79、 temperature applications down to -20OC but the air must be dried to this dewpoint to prevent ice formation气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Filtration and LubricationnValves should be supplied with clean dry air with or without lubricationnWater droplets and solid particle removal using a standa
80、rd 40 filter will normally be sufficientnValves are greased when manufactured, this alone will give a long lifetime to the seals and valve borenIf the air carries additional lubrication from a micro-fog lubricator the normal life of the valve will be extendednIf air is process dried to a very low de
81、wpoint lubrication is necessarynFor extreme high or low operating temperatures lubrication is necessary气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Solenoid ValvesnSolenoid valves are electro-pneumatic relaysnThe state of an electrical input controls the state of a pneumatic outputnSolenoid valves are the i
82、nterface between electronic control systems and pneumatic powernTypes are:Direct actingPilot operatedProportional气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Direct Acting Solenoid ValvesnUsed for:Signal generation and processing Control of small bore single acting cylindersnSingle station sub-base mountedn
83、Multi-station sub-base mountednIntegrated to larger valves to become solenoid pilot operated valvesn15, 22, 32 represent the mm width of the valveNugget 30Excel 15Excel 22Excel 32气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Principle of operationnThe double poppet armature is held by a spring against the in
84、let orifice sealing the supply at port 1nOutlet port 2 is connected to exhaust port 3nWhen the coil is energised the armature is pulled up closing the exhaust orifice and connecting the supply port 1 to the outlet port 2123123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Principle of operationnThe double pop
85、pet armature is held by a spring against the inlet orifice sealing the supply at port 1nOutlet port 2 is connected to exhaust port 3nWhen the coil is energised the armature is pulled up closing the exhaust orifice and connecting the supply port 1 to the outlet port 2112323气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明
86、 Chapter 5Manual OverridenTo test during set up or maintenance without energising the coilnIn position 0 the armature is in the normal closed position nTurning the cam with a screwdriver to position 1 lifts the armature to operate the valvenImportant to return to position 0 before the machine is res
87、tarted12013123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Manual OverridenTo test during set up or maintenance without energising the coilnIn position 0 the armature is in the normal closed position nTurning the cam with a screwdriver to position 1 lifts the armature to operate the valvenImportant to retur
88、n to position 0 before the machine is restarted01123123气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Direct Acting Solenoid ValvesnThe design is a balance between quantity of air flow (orifice diameter) and electrical power consumednThe higher the air flow, the larger the inlet orifice nThe larger the orific
89、e, the stronger the spring nThe stronger the spring, the greater the power of the magnetic fieldnThe greater the field, the higher the electrical power consumptionnThe desire for low electrical power for direct interface with PLCs and other electronic devices makes this design of valve ideal nThe ra
90、nge offers a variety of orifice sizes and electrical power ratings nThis design is used alone and as an integrated pilot to operate larger valves气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Cable EntrynTo provide a choice of cable entry orientation, the coil can be fixed in 90O alternative positions and the
91、 plug housing in 180O alternative positions 气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Interchangeable CoilsnA solenoid valve is designed to work with both AC and DCnA coil of any voltage AC or DC of the same power can be fitted or exchanged on the same stemnImportant. Low and high power coils cannot be e
92、xchanged. The orifice diameter and spring strength must match the coil power12V dc24V dc24V 50/60 Hz48V 50/60 Hz110/120V 50/60 Hz220/240V 50/60 Hzn100% E.D. The coil can be energised continuously气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Flow and Power RatingnTo help identify the solenoid valve body, the
93、orifice diameter is marked in the position shownn12V dc24V dc24V 50/60 Hz48V 50/60 Hz110/120V 50/60 Hz220/240V 50/60 Hzn2W = 1.0mm orifice diameter 6W = 1.6mm orifice diameter8VA = 1.6mm orifice diameter1.6011.6气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5DC CoilsnWhen a DC coil is switched on, about 85% of
94、 the power is developed before the armature can be pulled innLittle power is needed to hold it in, the rest of the power is given off as heatnCoils fitted with power saving circuitry detect armature movement and chop the power level nPower supply units can be smaller and running temperatures lower T
95、ime msWTime msWArmature drop outArmature pull in气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5AC Coils (inrush power)nAC solenoids are given a power rating with two values e.g. 4/2.5 VAn4 VA is the inrush power which lasts for a few milliseconds while the armature pulls inn2.5 VA is the continuing holding po
96、werTime msVA气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Inrush PowernAn AC coil has impedance which is mainly a combination of resistance and inductive reactance, because of this the pure resistance is lower than a DC coil of equivalent power nThe inductive reactance will be low before the armature is pull
97、ed in because the magnetic circuit is incomplete and less efficientnOn initial switch-on a higher current will flow until the armature is pulled in, then the magnetic circuit is fully made and the higher impedance controls the power to the designed levelnIf many AC solenoids are switched at the same
98、 time ensure the power supply is large enough气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Unsuppressed CoilsnAt the moment a coil is switched off, the collapsing magnetic field induces current trying to keep it energised. This is seen as high negative voltage at the switchnIf a reed switch is used a series
99、of arcs across the opening contacts will weld them togethernIf a solid state switch is used the semiconductor is destroyedNS+24 VO VP N P+24 VO V-1000V-1000V气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5SuppressionnIf the ends of the coil were connected at the moment of switch off, the induced current would
100、flow around the coil at low voltage fading to zero in about 200 millisecondsnFor DC this is achieved automatically by fitting a diode across the coilnA diode allows current to flow in one direction only and needs just 1.5V potential differenceNS+24 VO VP N P+24 VO V气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapte
101、r 5Voltage Dependent ResistornFor AC coils a diode will short circuit nA VDR is connected across the coil and works with AC and DC in either directionnWhen the voltage across a VDR is below a given threshold there is high resistance preventing current flow. nFor voltage above the threshold the resis
102、tance is low allowing current flownCurrent is blocked when the coil is energised as the threshold is above the working voltagenOn switch off, the induced voltage will rise above the threshold and flow around the coil and VDR at that value untill it fadesAC/DCVDR气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5P
103、ower On IndicationnVisual indication of the on/off state of a coil is useful for monitoring, and fault findingnThis feature can be included in the plug housing as an LED or a neon lampnFor retro-fitting, a LEG (light emitting gasket) can replace the normal gasket fitted between the plug and coilnZen
104、ner suppressionRLEDCoilZennerRectifierLED气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Explosion Proof SolenoidsnFor use in hazardous environments e.g. explosive fumes or dust, where sparks could could set of an explosionnComplies with EN50014 and EN50028nClassification EEx m ll T6 and EEx m ll T4nFits to va
105、lves and bases with a standard 22 mm solenoid interface 气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Nugget 120 Series气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Nugget 120 seriesnSlim compact light weight valve for high density installationnHigh flownWide range of mounting optionsnSingle in line sub-base side or
106、rear entrynFixed length manifoldsnModular sub-base single unit expandablenValve IslandnFieldbus Valve IslandsFixed length 6 station manifold with single and double solenoids气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Sub-basesnIn line sub-base with side ports, outlets in base or valve body topnIn line sub-
107、base with bottom ports, outlets in base or valve body topnFixed length manifold in1,2,4,6,8,10,&12 station sizes. Outlets in valve body top nAll with choice of gasket for integral solenoid supply from single or twin supply arrangements气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Modular Sub-basesnModular su
108、b-base expandable in single unitsnOutlets in sub-base side or valve topnOptions for Single, dual, three, four, five and twin pressure supply optionsn5/2 and 5/3 valvesnIntegral solenoid supplynManifolded external solenoid supply nManifolded solenoid exhausts气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve
109、 IslandnAll of the advantages of the modular sub-base system, plus solenoids pre-wired to multipole connectornIndicator lamps for each solenoidnBuilt in suppressionnDiagnostic indication on armature pull-innPower saving once the armature has pulled innRound IP65, D-sub IP40 or conduit connectionValv
110、e Island showing roundmultipole connector for solenoids气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Fieldbus Valve IslandnValve island with the solenoids pre-wired to a Fieldbus interface module of your choicenUp to 16 solenoidsnOpen systems nDevice-NetnInterbus-SnProfibus FMSnProfibus DPnAS-InterfacenClose
111、d systemsnSysmac (Omron)nJETWay-R (Jetter)POWERRUNNINGANYBUSREMOTE VALVE DRIVER 气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Nugget 120 Pilot SolenoidnInternal pilot supply and exhaust ducted to the main valve body for connection to a sub basenThe armature pushes the legs of the poppet to hold the exhaust s
112、eat open. It closes when the armature is pulled in气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Nugget 120 Pilot SolenoidnInternal pilot supply and exhaust ducted to the main valve body for connection to a sub basenThe armature pushes the legs of the poppet to hold the exhaust seat open. It closes when the a
113、rmature is pulled in气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve Body Sealing FacenThis view under the valve body shows the ducts for solenoid supply and exhaustsnBy selecting the appropriate gasket the solenoids can be integrally supplied for conventional or twin supply arrangementsnAlso there are ga
114、skets for external solenoid supply when the pressures to the valves main ports are unsuitable12345Solenoid Pilot Supply (end 14)Solenoid Pilot Exhaust (end 14)Solenoid Pilot Exhaust (end 12)Solenoid Pilot Supply (end 12)Hole for gasket location peg气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Functional Valv
115、e GasketsnFor Fixed Length and Single Station Sub-basesnInternal pilot supply (grey gasket type Y) Air at port 1 channeled to supply both solenoid pilots. Supplied with Fixed Length Manifolds and Single Sub-basesnTwin supply (yellow gasket type Z) Air at port 5 channeled to supply both solenoid pilo
116、ts. Supplied with Twin Supply Valves1234512345气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Functional Valve GasketsnFor Modular Sub-basenInternal pilot supply (black gasket type W) Air at port 1 channeled to supply both solenoid pilot valves. Supplied with all internal pilot supply valvesnExternal pilot sup
117、ply (red gasket type X) Air supplied to an external pilot port in the sub-base channeled to both solenoid pilot valves. Supplied with all external pilot supply1234512345气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve ApplicationsnTwin supplies to a 5 port valve are connected to ports 3 and 5, these can b
118、e used to instroke and outstroke a cylinder at different pressuresnPort 1 is used as a common exhaustnOn fixed length and single station sub-bases the yellow gasket will duct port 5 to the solenoid pilots 124531412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Valve ApplicationsnFor twin supply applications w
119、here the source pressures are too low to operate the valve, independent external pilot supplies are requirednFor modular sub- base systems and single station sub-bases this is a standard featurenFor fixed length manifolds there are special independent external pilot ported blocks (see next slide)124531412气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5Nugget 120 External Pilot nIndependent external pilot supply for use on fixed length manifolds nThe integral feed from the gasket is blocked气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5End气动技术双语电子教案气动技术双语电子教案 吴洪明吴洪明 Chapter 5
