Vickers Overhaul Manual Flow Controls Remote …

1 I-3419-SReprinted 6/1/96 Remote Flow control ValvesFCGT-02-A/B-**-11-(S30) Overhaul Manual Vickers Flow Controls2 Table of .. A. Purpose of Manual3.. B. General Information3.. 1. Related Publications3.. 2. Model Codes3.. A. General4.. B. Application4.. of Operation4.. A. Spool Adjustment4.. B. Theory of Operation4.. and Operating Instructions5.. A. Installation Drawing5.. B. Mounting5.. C. Piping and Tubing5.. D. Hydraulic Fluid Recommendations5.. E. Overload Protection5.. and Maintenance6.. A. Inspection6.. B. Adding Fluid to the System6.

2 C. Adjustments6.. D. Lubrication6.. E. Replacement Parts6.. F. Troubleshooting6.. A. General7.. B. Special Tool7.. C. Improvised Tools7.. D. Disassembly7.. E. Inspection, Repair and Replacement7.. F. Assembly9.. Procedure11.. A. Test Conditions11.. B. Test11.. Eaton Hydraulics, Incorporated 2000 All Rights Reserved3 Section I IntroductionA. Purpose Of ManualThis Manual describes the basic operational characteristicsand provides service, Overhaul and parts information for theVickers FCGT 02 Electrically Modulated Flow control . Theinformation contained herein pertains to the latest designseries as listed in Table General Information1.

3 Related Publications Installation dimensions arenot contained in this Manual . The installation drawing listedin Table 1 is available from any Vickers application engineer-ing office or from: Vickers , IncorporatedTechnical Publications5445 Corporate DriveP. O. Box 302 Troy, MI 48007-03022. Model Codes Variations within each basic modelseries are covered in the model code. Table 2 is a completebreakdown of the model codes covering these units. Serviceinquiries should always include the complete unit modelcode as noted on the 02 A 004 11 FCGT 02 B 004 11 FCGT 02 A 028 11 FCGT 02 B 028 11 FCGT 02 A 220 11 FCGT 02 B 220 11 FCGT 02 A 530 11 FCGT 02 B 530 11513850 ATable 1A Model with sleeve for lowerflow rangesB Model without sleeve forhigher flow rangesModel Code1345876126782345 Flow control valveCheck valve includedManifold or subplate mounted1/4 inch sizeDesign & modification9 With torque motor forremote controlNumber x 10 equals resistance in ohms/coil, e.

4 G. 004 x 10 = 40 ohms004 40 ohms028 280 ohms220 2200 ohms530 5300 ohms9F3 sealsTable 2. Model Code Breakdown4 Section II DescriptionA. GeneralAssembly of a typical FCGT flow control is shown in Figure1. In general, the flow control consists of an electrical torquemotor coupled to a metering spool. The metering spool anda compensated hydrostat stabilizes flow in the forwarddirection. A check valve is provided to allow reverse free flowthrough the flow Controls are available in two flow ranges; 5 to 250and 50 to 1000 cubic inches per minute, (in3/minute).

5 Flowranges are determined by different metering spooldiameters. The smaller the metering spool, the lower theflow ApplicationVickers application engineering personnel should beconsulted to determine correct methods of installation 1. Cutaway view of FCGT 02 * ** 11 TorqueMotorHydrostatCheckValveCoverBodyM eteringSpoolSection III Principles of OperationA. Spool AdjustmentThe metering spool is adjusted at the factory for a minimumflow of 5 in3/ minute, ( A Models), and 50 in3/ minute for B Theory Of OperationConsider the FCGT Flow control Valve as being two distinctand separate systems one a standard compensated flowcontrol with a fixed throttle setting and secondly anelectrically modulated device (torque motor), used to varythe throttle opening.

6 (Refer to the pictorial diagram Figure 2,during the following explanation.)Flow Controls Flow Controls work on the principle thatflow through an orifice will be constant when the pressuredrop across the orifice is held constant. Flow (Q) through anorifice is directly proportional to the orifice area (A) and thesquare root of the pressure drop across it (DP ).Q+ADP Q = USgpmA = in2 Valid for short orificenP PSI drop across orificeAssume throttle orifice A (the metering spool orifice) isopened to allow 200 cubic inches / minute, (in3 / minute), flowthrough the valve to an external load circuit.

7 The external loadcircuit develops 1000 PSI. Inlet pressure to the valve is valve(Reverse free flow)SpringSpring compensated hydrostatInletOrifice B OutletUpstream side of orifice A Set screw threaded intotorque motor armature A Set for 5 in3 / min. B Set for 50 in3 / spool(Throttle)Orifice A Tank drainPressureIntermediate pressureOutlet pressureTank pressureFigure 2. Pictorial Diagram5 The total pressure drop across the valves two series orifices A and B must equal 1000 PSI, (the difference betweeninlet and outlet pressures). The normal drop across orifice A is between 60 and 80 PSI.

8 (Use 75 PSI for thisexplanation.) Orifice B will drop 925 PSI, the total of thetwo pressure drops is the difference between inlet and the work load increases, the outlet pressure increases. Tokeep a constant flow, the pressure drop across orifice A must not change. This is accomplished as follows:The increased outlet pressure is sensed against the springend of the hydrostat, causing it to move down, increasing thearea of orifice B and reducing the pressure drop across increases the pressure available at the up stream sideof orifice A . 200 in3/minute will continue to flow as long as a75 PSI pressure drop is maintained across orifice A.

9 If the work load were to decrease, (output PSI lower), asimilar set of events will begin, except in the oppositedirection. The hydrostat will move up. Orifice B reduces insize, increasing the pressure drop across it, lowering thepressure at the up stream side of orifice A and a constant200 in3/minute will continue to flow through the Motor A high force permanent magnet torquemotor imparts linear motion to the torque motor deflection of the armature is directly proportional tocurrent through he torque motor coils. This armature islinked to the metering spool with a wire and set screw.

10 Whencurrent is applied to the torque motor coils, the armature isdeflected to a certain position and the metering spoolfollows, opening or closing orifice A . When orifice A changes, the flow control will vary flow through the valve andhold it constant at the new setting of the metering spoolregardless of IV Installation and Operating InstructionsA. Installation DrawingsThe installation drawing listed in Table 1 will show installationdimensions and port MountingThe FCGT- 02-*-11 Flow control Valve is designed for man-ifold or subplate mounting. Refer to the installation drawingfor subplate Piping And Tubing1.