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ASCO Valves Are Designed and Tested for Continuous Service

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ASCO Valves Are Designed and Tested for Continuous Service SOLENOID OPERATORS, COILS & SPARE PARTS KITS Coil identification and basic design considerations COILS Coils used in ASCO valves are designed and tested for continuous service. They all meet the thermal endurance specifications according to IEC 216. Allowable Allowable Max. (1) Insulation Max. Oper. Max. Temp. Ambient Temp. class Rise Temp. Ref. (°C ) (°C * ) ( °C ** ) E 120 80 40 - 80 75 T 95 60 - 100 55 2) T F 155 100 55 2) B 105 50 B 130 25 F 80 100 T 105 75 B 120 60 - H 180 120 60 2) T 120 60 2) B 130 50 F 155 25 P Fig. 1 1) Additional reference identification letter for coil types : XM5, M6, M6-II, MXX, MXX-II, M12 (Ex. : FT, FB, FF, HT) 2) Catalogue number coils 238xxx-xxx * Coil's own temperature rise due to energisation According to the type of coil used, the CALCULATIONS ** Including effect of fluid temperature at catalogue rated solenoid operator’s maximum ambient limits (Electrical characteristics, solenoid operator’s temperature (given under “Electrical char- For direct acting solenoids we can calculate ambient temperature range). acteristics” in the specific catalogue pages) the solenoid pull force by means of the fol- including fluid temperature effects may be lowing rough equation: The construction of the majority of coils is in 75, 60, 50, or 25°C. accordance with IEC 335 standards. Other Determining factors may be either: Fs = p . A (N) international standards (UL etc.) are also met (contact us). a) Temperature considerations (own tem- Fs = solenoid pull-force (N) 5 Standard coils are available for insulation perature rise) p = pressure (Pa) (10 Pa = 1 bar) classes E, F and H. The insulation class A = orifice area (m2) determines the coil’s maximum operating b) Power considerations temperature for a specific life: Example - Class H: 30 000 hours c) Ambient and/or fluid temperature An average solenoid will have a pull force of - Class F: 20 000 hours approx. 15N. To use this solenoid on a pres- d) Higher temperature rise, as result of sure differential of 1MPa (10 bar), we can The temperature rise of continuously en- increased wattage (required for valve calculate the maximum orifice diameter. ergised coils depends on size and power pressure ratings). consumption. This, in turn, determines the Fs = p . A 15 = 106 . A -5 2 maximum differential pressure rating of a ASCO offers coils, distinguished by dimen- A = 1,5 . 10 m 2 valve as indicated in the catalogue. sion and electrical power: A = 1/4.π.d d = 4,4 mm CM5, CM6, CMXX, CM12, CM22, CM25, An example for insulation class F is given CM30, CM40, JMX, ANX, AMX, BMX and For low pressure applications such as in fig 1. The insulation is designed for the C22A. gas burners, automatic dispensing or low coil to be operated at temperatures in vacuum systems up to 0,1 MPa the orifice accordance with class F, i.e. 155°C. The For more details on coils and identification, diameter equals to 19,5 mm. max. temperature rise of the coil when see Section J / V1100, pages 2 to 5. energised is limited, depending on the type The internal pilot-operated constructions of coil (e.g. 80°C (FT), 95°C, 105°C (FB), (floating diaphragm or floating piston) use 130°C (FF)). a small orifice (the pilot) to control the pressure to the diaphragm or piston. Large main orifices can be opened or closed at reasonable pressure up to 15 MPa. 00022GB-2018/R01 All rights reserved. design and specifications are subject to change without notice. Availability, All leaflets are available on:www.asco.com General & Engineering Information - 43 Basic design considerations - SOLENOID OPERATORS, COILS & SPARE PARTS KITS BASIC DESIGN CONSIDERATIONS 1 The electrical field To use solenoid as a driver for valves we + B (T) 0,8 have to learn first how the magnetism, gen- erated by the solenoid, can be converted 0,6 into mechanical energy. If a certain voltage is applied to the coil of the solenoid an electrical current will flow 0,4 through its windings and creates a magnetic field around the coil. 0,2 This field depends on the amount of cur- rent, number of windings and length of the -H (A/m) +H (A/m) coil and can be expressed by the following -2000 -1500 -1000 -500 0 500 1000 1500 2000 equation: -0,2 IN. H = (A/m) []IN.=ΣHd. -0,4 We discover, however, that the conduc- tance of magnetic field-lines differs for all kind of material. -0,6 This conductance is called: permeability "µ". - B (T) -0,8 For vacuum the permeability : -7 -1 µ0 = 4.π.10 (H/m) or (Vs/Am) µ = µo . µr [µ = B/H] ASCO's core and plugnut material is special µr air = 1 chemical high compatible ferromagnetical A.C. stainless steel. R We distinguish: If tables are used, the following equation - diamagnetical: should be applicable: µr < 1 (bismuth, antimony) - paramagnetical: B = µ . µ . H (T) o r L µr = 1 (aluminium, copper) - ferromagnetical: AC and DC Solenoids I As it is important to know the electrical µr >1 (iron, nickel, cobalt) field we have to know therefore the current µ through the coil. 2 To identify the proper " r" or induction 0.r.N .A For DC constructions we can easily calcu- L = (H) "B" we can make use of the so-called hysteresis-cycle-curves for the feromag- late the current with the equation: L = C . µr netical materials. X = 2.π.f . L U L I = (A) U U R I == Z 22 XR+ However, for AC constructions we have not ()L only to deal with pure ohmical resistance, but also with AC-resistance, the so-called reactance 'X '. I L To find the impedance 'Z' we have to D.C. combine the 'XL' and 'R' values in a vec- S tor diagramme. Now we can calculate the L current by: R U I = (A) Z The 'X ' value depends on the air gap L L between core and plugnut and is smaller when the gap is big. I I Therefore we can find a difference between the current through the coil when the core is in its lower position (inrush) and a current with the core in its upper position For "DC" L (holding). I i = I h U I = inrush I = ()A i R I h = holding 00022GB-2018/R01 All rights reserved. design and specifications are subject to change without notice. Availability, All leaflets are available on:www.asco.com 44 - General & Engineering Information Basic design considerations - SOLENOID OPERATORS, COILS & SPARE PARTS KITS Pull force of a magnet With the knowledge of the electrical field graph A and induction we can determine the sole- noid driver force by means of the following 25 equation: 20 B2.A (I.N. .)2 A F = = r . N 15 2 ( ) 2.0 L 2.0 10 B As the three graphs on the left show, the A 5 airgap between core and plugnut deter- mines the induction "B" and therefore the PULL FORCE (N) 0 1 2 3 456 7 pull force "F", the so-called pull-stroke STROKE (mm) curves do show for each solenoid their typical curves. H = Magnetic field strength (A/m) A = CM6-FT, CM25-5 I = Electrical current (A) B = CM6-FB, CM30-8 N = Number of turns (1) B = Magnetic flux density (T) µo = Permeability of vacuum (H/m) µr = Relative permeability (1) A = Area of core (m2) C = Constant graph B 30 25 20 15 A.C. (alternating current) R 10 PULL FORCE (N) B 5 A L 0 I 3 6912 C H XL Z Z STROKE (mm) Z HOT XL Z COLD A = CMXX-FT, CM40-10 R = 2 . R B = CMXX-FB, CM40-14 H C U IC = ZC U IH = R RCOLD R HOT 1,1.ZC C H graph C With : U = voltage D.C. (direct current) I = current cold 40 C R IH = current hot R = resistance cold 30 C RH = resistance hot 20 ZC = impedance cold L ZH = impedance hot 10 B A I PULL FORCE (N) If a coil is heated up in a certain time the coil resistance increases drasticly. 0 3 6 91215 18 We can see that to double the coil resist- STROKE (mm) U ance, when valves are hot, halves the IC = RC current for DC but only has a minor effect of ±10% on AC coils. U A = CM12-FT I H = 1/2.IC B = CM12-FB 2.RC 00022GB-2018/R01 All rights reserved. design and specifications are subject to change without notice. Availability, All leaflets are available on:www.asco.com General & Engineering Information - 45 Basic design considerations - SOLENOID OPERATORS, COILS & SPARE PARTS KITS I x N 180° Magnetic field energised by the main coil. 270° 90° 360° Z U X Z I = ()A XLL Z I x N Magnetic field (from the shading coil) generated by the main field, however with a phase shift of approx. 90°. R RESULTING FORCE F Combination of the pull forces from main and shading coil. Differences between AC and DC sole- DC Service noids a) Inrush current equals to holding AC service current AC solenoids are always equipped with b) Power consumption and pull force sh u U X ZinrA a shading coil in the plugnut (stationary depend on temperature XL L Z IA = Z A core) and the top of the core is flat faced c) Solenoid operates quietly and perpendicular. d) Not sensitive to dirt e) The coils have more windings (copper) R DC service than AC coils There are two solenoid valve categories: The first category with identical AC and DC Power Consumption for AC: design offers easy adaption of the same valve to AC or DC; full interchangeability is (W) with: P = U.I.Cos ensured for alternating or direct current.
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