A Study of the Pneumatic Counterweight of Machine Tools Conventional and Active Pressure Control Method
|
|
- Elijah Black
- 5 years ago
- Views:
Transcription
1 890 A Study of the Pneumatic Counterweight of Machine Tools Conventional and Active Pressure Control Method Ming-Hung TSAI and Ming-Chang SHIH The pneumatic counterweight method is a suitable counterweight method used for machine tool owing to its high speed and force capacity, combined with low price and clean operation. However, the preset pressure cannot be hold at higher traveling rate if the conventional pneumatic counterweight is applied. In this study, rather than using the conventional pressure compensation method, the active pressure control method was designed as an alternative to the pneumatic counterweight driven by a linear motor. The fuy sliding mode controller was designed and implemented for regulating the pressure using the servo valve. The experimental results demonstrate that the variation of the pressure in the pneumatic cylinder can be hold within the range ±15 kpa by using active pressure control method. Key Words: Active Pressure Control, Pneumatic Counterweight, Fuy Sliding Mode Control 1. Introduction The pneumatic counterweight system enables machine tools to support the weight of a spindle of the machine tool by using air cylinders. The actuator force output is produced by the pressure differential acting across the piston and can be controlled by regulating the pressure in cylinder chambers. The system takes advantage of increasing traveling rate, saving power and reducing the effect of gravity. The pneumatic counterweight system is a suitable method of counterweight method because of its high speed and force capacity, combined with its low price and clean operations. However, if the preset pressure of the cylinder cannot be hold, the actuator force output is not a constant and the feed rate and machining precision is involved. Conventionally, the pneumatic pressure compensation method applied for the pneumatic counterweight system of the servo motor driven machine tool is designed to connect a large air tank with a pneumatic cylinder, so that pressure change in the pneumatic cylinder can be reduced due to the spindle motion. The air tank is connected to the compressed air source, the compressor, and the pressure regulator or the pressure switch is added to achieve the constant pressure. However, if the spindle of the ma- Received 1st March, 2006 No ) Department of Mechanical Engineering, National Cheng Kung University, No.1, Ta-Hsueh Rd., Tainan, 701, Taiwan, R.O.C. mcshih@mail.ncku.edu.tw chine tool travels at a faster rate, a constant pressure cannot be hold using the conventional method and moreover connecting a large air tank to cylinder would be useless in this situation. Recently, several investigations have developed some different algorithms for controlling pneumatic actuator. Ben-Dov and Salcudean 1) developed a linear force controller to modulate force by voice-coil flapper valves and low-friction cylinders. Shih and Hwang 2) developed modified differential pulse width modulation PWM) method to eliminate the dead one and to improve the nonlinear characteristics between the pressure differences of the cylinder. In Shih and Ma 3), the fuy PWM control method was developed and applied to control the position of a pneumatic cylinder with high speed solenoid valves. Also, Sorli and Pastorelli 4) developed PNM/PWM controller to control chamber pressure of cylinder by two pairs of monostable 2-way valves. Khayati, Bigras and Dessaint 5) developed tractable state-feedback synthesis technique and H controller to control the pneumatic actuator force. Furthermore, Richer and Hurmulu 6) used reduced order sliding mode controller to control pneumatic force with servo valve and obtained a 20 H bandwidth. S. Shibata et al. 7) designed a fuy controller with fuy virtual reference generator to improve the rise time. In this study, an active pressure control method was developed and implemented on the pneumatic counterweight system driven by high speed linear motor. The cylinder pressure was directly regulated with the servovalve. Considering the air compressibility and highly non-
2 891 Fig. 1 The conventional pneumatic counterweight system of machine tool linear behavior, this study designed the fuy sliding mode controller for the active pressure control method to simplify the system analysis and controller design. The fuy sliding mode controller was designed on the basis of the sliding mode control law 8), 9), 12). The proposed active pressure control method is simple, effective and easy to implement on the pneumatic counterweight of the machine tools. 2. System Description Figure 1 shows the layout of the conventional pneumatic counterweight system of the machine tool. This paper builds the test stand and study the conventional and active pneumatic counterweight system. Figure 2 shows the layout of the test stand. 1 ) Conventional pneumatic counterweight system: Fig. 3 schematically represents the conventional pneumatic counterweight test stand. The cylinder pressure was stabilied by connecting cylinder to the air tank and the air tank pressure was regulated using pressure regulating valve. 2 ) Active pneumatic counterweight control system: Fig. 4 schematically represents the active pneumatic counterweight test stand. An IBM 32 bit compatible microcomputer was applied as a controller. Initially, the computer sent a control signal to trigger an electric control unit ECU) to drive the linear motor. The mass flow rate entering the cylinder is controlled by the servo valve, which is controlled by the computer. The pressure of the pneumatic cylinder or force applied by cylinder can be controlled through controlling mass flow rate using servo valve. Furthermore, the pneumatic force compensates 95 kg of the vertically moved mass driven by the linear motor. The displacement of the cylinder and air pressure are measured by pulse scale and pressure sensor and fed back to the computer. After calculation and comparison, the control sig- Fig. 2 The layout of the test stand nals are sent to control the ECU and linear motor. Finally, the experimental results were compared to those obtained using the conventional method. 3. Basic Equations The model of the pressure control system regulated by servovalve is shown in Fig. 5. This study primarily investigates the dynamics of the pressure in cylinder chamber and is not concerned with the dynamics of the linear motor. The governing equations are derived as follows under the following assumptions: A1) gas is ideal, A2) gas density is uniform in the chamber, A3) flow leakages are neglected, and A4) pressure of air supply is stable in the system Piston-load dynamics The equilibrium equation for the piston can be expressed as M +βż+ F f = F m +P b A b P a A a + P e A r ) Mg 1) where M is the external load mass, is the piston position, β is viscous friction coefficient, and F f is friction force. The friction force is relation to the velocity of the piston and the characteristic of friction force is shown in Fig. 6. The friction force is described by F fm if ż = 0andF fm2 F fm F fm1 F fm1 F f 1 )e 5ż/v c1 +F f 1 if 0 < ż <v c1 F f = F f 1 +a 1 ż if ż v c1 2) F fm2 F f 2 )e 5ż/v c1 +F f 2 if 0 > ż >v c2 F f 2 +a 2 ż if ż v c2
3 892 F m is the force applied by linear motor, P a and P b are the absolute pressures in cylinder chambers, P e is the absolute ambient pressure, A a and A b are the piston areas, and A r is the rod area. The weight of mass is balanced by the actuator force output, produced by the pressure differential acting across the piston Model of the cylinder chambers for the conventional method The conventional pressure control method for pneu- matic counterweight system is to connect the air tank without using servovalve to directly control the pressure in the cylinder chambers. The following equations are obtained: The air in the cylinder chamber A is directly discharged to the atmosphere, so we consider the control volume V b, with densityρ b,massm b, pressure P b,andtemperature T b, the dynamic of the pressure P b can be written as 1), 10) : Fig. 3 Schematic construction of the conventional pneumatic counterweight test stand Fig. 4 Schematic construction of the active pneumatic counterweight test stand a) b) Fig. 5 Schematic representation of the valve controlled pressure control system for a) ż > 0 and b) ż < 0
4 893 Fig. 6 Friction model of the piston dp b = kp b dt ż+ krt b ṁ b 3) A b where is the displacement of cylinder. Mass rather than volume flow rate is generally used because of the compressibility of air. The equation for the mass flow entering through an effective area A t of an orifice to the air tank can be written as: ) PD1 ṁ t =C 1 A t f 1 signp b P t ) 4) TU1 PD1 ) PD1 if P D1 f 1 = P >C r U1 k 2 R k +1 ) 1/k ) k 1)/k 2k Rk 1) 1 PD1 P U1 if P D1 C r ) k+1)/k 1) where ṁ t is the mass flow entering the air tank, C 1 is discharge coefficient, and C r is the pressure ratio that divides the flow regimes into unchocked and chocked C r = for air). P upstream) and P D1 P downstream) are defined as = maxp b,p t ), P D1 = minp b,p t ) where P b is the pressure in cylinder s chamber B, and P t is the pressure in air tank. The mass flow rate of cylinder s chamber B can be presented by ṁ b = ṁ t, while the pressure dynamics of cylinder s chamber B is expressed as: dp b = kp b dt ż krt b ṁ t P b,p t ) 5) A b This equation indicates that the pressure P b is stable if the air tank can provide a corresponding mass flow rate ṁ t, when the mass moves at traveling rate ż. The tank volume is large enough and the pressure variation of the tank can be ignored. Thus we can assume the tank pressure P t is equal to preset pressure. However, the mass flow rate is smaller between the cylinder and the air tank when the cylinder pressure is approximately equal to the tank pressure. Consequently the higher traveling rate produce a larger variation of the cylinder pressure, and connecting a large air tank to cylinder is useless in this condition Model of the cylinder chamber for the active control method To stabilie the cylinder pressure when the mass moves at a higher traveling rate, this study uses a servovalve to control the cylinder pressure directly. The dynamics of valve spool can be approximated using a first order differential equation because the spool inertial force is much smaller than the force applied by the internal springs of the valve. So, the valve dynamics may approximately be described as: ẋ v = h v x v +e v u 6) where x v is the spool displacement from central position, h v and e v are positive constant, and u is the control signal. The servo valve performance can be obtained from the operating instructions 14) : the critical frequency at the maximum movement stroke of the piston spool is 90 H. Because the movement of valve spool is fast compared with cylinder piston movement, the valve dynamic effects can usually be neglected in this control system. The valve spool stroke can be considered as proportional to the control signal u. Theeffectivearea of servo valveis expressed as: A v = w ev u = k v u 7) h v where w is the area gradient of servovalve. The equation for the mass flow through an the effective area A v of servo valve can be written as: ) PD2 ṁ v =C 2 A v f signu) 8) TU2 f PD2 PD2 ) if P D2 = P >C r U2 k 2 R k +1 ) 1/k ) k 1)/k 2k Rk 1) 1 PD2 P U2 if P D2 C r ) k+1)/k 1) where ṁ v is the mass flow through the valve orifice, C 2 is discharge coefficient, and C r is the pressure ratio that divides the flow regimes into unchocked and chocked C r = for air). P upstream) and P D2 P downstream) are defined as { PU2 = P s,p D2 = P b if u 0 = P b,p D2 = P e if u < 0 where P s is the supply pressure, and P e is the discharge pressure.
5 894 The mass flow rate of the cylinder s chamber B thus can be represented by ṁ b = ṁ v ṁ t, and the pressure dynamics of cylinder is as follows: Table 1 Fuy rule table dp b = kp b dt ż+ krt b [ṁ v P s,p b,p e ) ṁ t P b,p t )]9) A b The pressure in the cylinder s chamber B must be constant in order that the actuator force output is constant. Therefore the mass flow rate though the servovalve must be controlled using active pressure control method, and the pressure change can be reduced when the mass moves at a higher traveling rate. 4. Controller Design When controlling a plant, there is so much mathematical representation used on designing controller. To simplify the system analysis, this study developed the fuy sliding mode controller based on the sliding mode control law 9), 12). This study assumes that the system temperature to be a constant T, and ignore the mass flow rate between the cylinder and tank. The control problem is to get the pressure P b to track the preset pressure P d. The sliding mode index S could be written as: S = P b P d 10) The sliding mode equation becomes Ṡ = Ṗ b 11) Substituting Eqs. 7) and 8) into 9) and setting ṁ t = 0, we can obtain: Ṗ b = kp b ż+ C 2kk v R TP u2 f P D2 / ) u 12) A b Let b = C 2kk v R T, A b the Eq. 12) can be rewritten: Ṗ b = kp b ż+ bp u2 f P D2 / ) u 13) The sliding mode equation can be rewritten: Ṡ = Ṗ b = kp b ż+ bp u2 f P D2 / ) u 14) Assume parameter b may be various in a range: 0 b min b b max Let ˆb = b min b max ) 1/2 and Ṡ = 0, we can get the nominal control law: kp b û = Ż 15) ˆb f P D2 / ) We use the fuy control law u fuy to replace the discontinuous component and the control signal u can be written as: kp b u = û+u fuy = ˆb f P D2 / )ż+u fuy 16) Substituting Eq. 16) into 14), we can get: Ṡ = b/ˆb 1)kP b ż+ b f P D2 / ) u fuy 17) Fig. 7 Fuy membership functions According Lyapunov theory, all the fuy sliding rules should satisfy the requirement as follows: S Ṡ = b/ˆb 1)kP b żs + b f P D2 / ) u fuy S < 0 18) b f P D2 / ) The term in Eq. 18),, is positive. Therefore, in this condition, reducing u fuy leads to decrease S Ṡ as S is positive and increasing u fuy leads to decrease S Ṡ as S is negative. The above statements can be summaried as a rule base for the fuy logic controller and the rule table shown in Table 1. The triangular membership functions for the input S, Ṡ and output u f were shown in Fig. 7 and the center-of-gravity method was used
6 895 Fig. 8 Scheme of the pneumatic pressure servo control system Fig. 10 Time responses of the system using fuy sliding mode controller with different setting velocity Fig. 9 The time response of the conventional pneumatic counterweight system with different setting velocity for defuification. Figure 8 shows a block diagram of the pneumatic pressure servo control system. 5. Experimental Results The conventional pneumatic counterweight system and the active pneumatic counterweight control system were described above. Their system performance and experimental results are presented as follows. The supply pressure was 600 kpa, and the setting pressure of the lower chamber of cylinder was 320 kpa. The cylinder provides force of 931 N to support the weight of the moved mass. The inner and rod diameter of the cylinder were 0.08 m and 0.03 m, respectively, while the tank volume was 0.08 m 3. The weight of the moved mass driven by linear motor was 95 kg and the stroke was 0.2 m. The different velocity limits are set for the linear motor to clarify the system performance. The sampling frequency was 100 H. Furthermore, the traveling rate was estimated by using velocity estimator based on the least-squares from the discrete position versus time data 13). Figure 9 shows the pressure responses of the counterweight system using the conventional pressure control method. The experimental results show that the higher traveling rate leads to lager pressure variation with the largest pressure variation occurring at the largest traveling rate. The largest pressure variations of the cylinder were 60 kpa in the downward motion and 40 kpa in the upward motion. Moreover, the maximum force change was N in the motion process, but the balanced force is just 931 N. Furthermore, the experimental results show that the largest pressure variation in the downward motion exceeds that in the upward motion. The pressure variation can be found to be asymmetrical from experimental results and the asymmetrical conditions of the pressure variation are more obvious for the mass with higher traveling rate. Clearly the motion of the linear motor is involved in these problems, so using the active pressure control method is necessary for the mass with higher traveling rate. Next, this study presents the experimental results using the active pressure control method. The experimental results in Fig. 10 were regulated using the fuy sliding mode control method. The pressure variation e and ė have to be multiplied by the scaling factors, Ge and Gv, sothat the products are normalied in the interval [ 1, 1]. The output signal of the fuy sliding mode controller, u f,is
7 896 multiplied by the scaling factor, Gu, to correspond with actual operating voltage of the servo valve. The larger scaling factors, Ge and Gv, result in good performance and fast response but may cause oscillatory response. After some trial and error, the scaling factors of the fuy sliding mode control are Ge= 4, Gv = 1.5 andgu= 0.7. In Fig. 10, the largest pressure variation is lower than 15 kpa and the variation of the pneumatic force was lower than 64.8 N in the motion process. These experimental results demonstrate that using the active control method is useful for stabiliing the cylinder pressure and providing more stable actuator force output for the pneumatic counterweight control system. Moreover the pressure variation in the pneumatic cylinder can be controlled to be within the range ±15 kpa in this study. 6. Conclusions This study designed the active pressure control method to modulate the cylinder pressure with a servovalve. The experimental results yield the following conclusions: 1. A lager pressure change would be occurred when the spindle of the machine tools move at a faster speed using the conventional pneumatic counterweight system. 2. The active pressure control method can efficiently reduce the pressure change and provide more stable actuator force output for the pneumatic counterweight system. 3. The pressure variation in the pneumatic cylinder can be controlled to be within ±15 kpa using the active pressure control methods in this study. 4. This study may provide a useful reference for researchers to improve the feed rate and the machining precision for the machine tool. Acknowledgement The support provided by National Science Council of Taiwan NSC E ) is greatly appreciated. References 1 ) Ben-Dov, D. and Dalcudean, S.E., A Force-Controlled Pneumatic Actuator, IEEE Transactions on Robotics and Automation, Vol.11, No ), pp ) Shih, M.C. and Hwang, C.G., Fuy PWM Control the Positions of a Pneumatic Robot Cylinder Using High Speed Solenoid Valves, JSME Int. J., Ser.C, Vol.40, No ), pp ) Shih, M.C. and Ma, M.A., Position Control of a Pneumatic Cylinder Using Fuy PWM Control Method, Mechatronics, Vol.8, No ), pp ) Sorli, M. and Pastorelli, S., Performance of a Pneumatic Force Controlling Servosystem: Influence of Valves Conductance, Robotic and Autonomous Systems, Vol.30, No ), pp ) Khayati, K., Bigras, P. and Dessaint, L.-A., A Robust Feedback Lineariation Force Control of a Pneumatic Actuator, IEEE International Conference on Systems, Man and Cybernetics, 2004), pp ) Richer, E. and Hurmulu, Y., A High Performance Pneumatic Force Actuator System: Part II Nonlinear Controller Design, Journal of Dynamic Systems, Measurement, and Control, Transactions of the ASME, Vol ), pp ) Shibata, S., Ben-Lamine, M.S., Toyohara, K. and Shimiu, A., Fuy Control of Vertical Pneumatic Servo Systems Using Virtual Reference, JSME Int. J., Ser.C, Vol.42, No ), pp ) Li, T.-H. and Tsai, C.-Y., Parallel Fuy Sliding Mode Control of a Spring Linked Cart-Pole System, IECON Proceedings Industrial Electronics Conference), Vol ), pp ) Lhee, C.-G., Park, J.-S., Ahn, H.-S. and Kim, D.-H., Sliding Mode-Like Fuy Logic Control with Self- Tuning the Dead Zone Parameters, IEEE Transactions on Fuy Systems, Vol.9, No ), pp ) Richer, E. and Hurmulu, Y., A High Performance Pneumatic Force Actuator System: part I Nonlinear Mathematical Model, Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME, Vol ), pp ) Slotine, J.J.E. and Li, W., Applied Nonlinear Control, 1991), Prentice Hall. 12) Renn, J.-C. and Liao, C.-M., A Study on the Speed Control Performance of a Servo-Pneumatic Motor and the Application to Pneumatic Tools, International Journal of Advanced Manufacturing Technology, Vol.23, No ), pp ) Brown, R.H., Schneider, S.C. and Mulligan, M.G., Analysis of Algorithms for Velocity Estimation from Discrete Position Versus Time Data, IEEE Transactions on Industrial Electronics, Vol.39, No ), pp ) FESTO Inc., Operating Instructions of MPYE-Type Servo Valve, FESTO Inc., 2004).
Programmable Valves Enable Both Precision Motion Control and Energy Saving
Programmable Valves Enable Both Precision Motion Control and Energy Saving Dr. Bin Yao Purdue University West Lafayette, IN 47907, USA 1 Outline Development of Programmable Valves Control of Programmable
More informationWATER HYDRAULIC SYSTEM FOR HIGH SPEED CYLINDER DRIVE
OS3-3 Proceedings of the 7th JFPS International Symposium on Fluid Power, TOYAMA 2008 September 15-18, 2008 WATER HYDRAULIC SYSTEM FOR HIGH SPEED CYLINDER DRIVE Shigeru IKEO*, Hirotaka NAKASHIMA** and
More informationGerald D. Anderson. Education Technical Specialist
Gerald D. Anderson Education Technical Specialist The factors which influence selection of equipment for a liquid level control loop interact significantly. Analyses of these factors and their interactions
More informationWATER HYDRAULIC HIGH SPEED SOLENOID VALVE AND ITS APPLICATION
WATER HYDRAULIC HIGH SPEED SOLENOID VALVE AND ITS APPLICATION Akihito MITSUHATA *, Canghai LIU *, Ato KITAGAWA * and Masato KAWASHIMA ** * Department of Mechanical and Control Engineering, Graduate school
More informationINSTRUMENTS A THERMAL MASS FLOW SENSOR USING A CONSTANT DIFFERENTIAL TEMPERATURE ABOVE THE AMBIENT GAS TEMPERATURE
TELEDYNE HASTINGS TECHNICAL PAPERS INSTRUMENTS A THERMAL MASS FLOW SENSOR USING A CONSTANT DIFFERENTIAL TEMPERATURE ABOVE THE AMBIENT GAS TEMPERATURE Proceedings of FEDSM 98 1998 ASME Fluids Engineering
More information3 1 PRESSURE. This is illustrated in Fig. 3 3.
P = 3 psi 66 FLUID MECHANICS 150 pounds A feet = 50 in P = 6 psi P = s W 150 lbf n = = 50 in = 3 psi A feet FIGURE 3 1 The normal stress (or pressure ) on the feet of a chubby person is much greater than
More informationSimulator For Performance Prediction Of Reciprocating Compressor Considering Various Losses
Simulator For Performance Prediction Of Reciprocating Considering Various Losses Aditya S. Bawane 1, Dr. V.K. Bhojwani 2, Mitali B. Deshmukh 3 1 (Mechanical Engineering Department, JSCOE, S.P. Pune University,
More informationINTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY Dynamic Model of Pressure Regulating Valve Ahmed Abed *
IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY Dynamic Model of Pressure Regulating Valve Ahmed Abed * Automotive and Marine Engineering Department/ Collage of Technological
More informationarxiv: v1 [cs.ro] 5 Mar 2017
Pneumatic Modelling for Adroit Manipulation Platform Visak CV and Vikash Kumar arxiv:.v [cs.ro] Mar Abstract ADROIT Manipulation platform is a pneumatically actuated, tendon driven 8 degree of freedom
More informationThe Estimation Of Compressor Performance Using A Theoretical Analysis Of The Gas Flow Through the Muffler Combined With Valve Motion
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering The Estimation Of Compressor Performance Using A Theoretical Analysis Of The Gas Flow Through
More informationPrecise Control of the Piston Position and the Pressure of Cylinder Chambers for the Pneumatically Actuated Leg
WSEAS TRANSACTIONS on SYSTEMS and CONTROL Precise Control of the Piston Position and the Pressure of Cylinder Chambers for the Pneumatically Actuated Leg ZHE LI Department of Mechanical Engineering Harbin
More informationCHARACTERISTICS OF LEAK DETECTION BASED ON DIFERENTIAL PRESSURE MEASUREMENT
CHARACTERISTICS OF LEAK DETECTION BASED ON DIFERENTIAL PRESSURE MEASUREMENT Harus L.G..*, Maolin CAI**, Kenji KAWASHIMA** and Toshiharu KAGAWA** * Graduate student of Mechano-Micro Engineering Dept., Tokyo
More informationSTIFFNESS INVESTIGATION OF PNEUMATIC CYLINDERS. A. Czmerk, A. Bojtos ABSTRACT
59 th ILMENAU SCIENTIFIC COLLOQUIUM Technische Universität Ilmenau, 11 15 September 2017 URN: urn:nbn:de:gbv:ilm1-2017iwk-148:6 STIFFNESS INVESTIGATION OF PNEUMATIC CYLINDERS A. Czmerk, A. Bojtos Budapest
More informationA New Way to Handle Changing Fluid Viscosity and the Full-to-empty Effect
A New Way to Handle Changing Fluid Viscosity and the Full-to-empty Effect Nordson EFD, 40 Catamore Blvd., East Providence RI 02914 www.nordsonefd.com A New Way to Handle Changing Fluid Viscosity And the
More informationA NEW GOLF-SWING ROBOT MODEL UTILIZING SHAFT ELASTICITY
Journal of Sound and Vibration (1998) 17(1), 17 31 Article No. sv981733 A NEW GOLF-SWING ROBOT MODEL UTILIZING SHAFT ELASTICITY S. SUZUKI Department of Mechanical System Engineering, Kitami Institute of
More information6 th International Conference on Trends in Agricultural Engineering 7-9 September 2016, Prague, Czech Republic
EQUIPMENT FOR TESTING STABLE FLOOD DEFENSES L. Ševčík Technical university in Liberec, Liberec, Czech Republic Abstract Issues of the impactor testing flood defenses in this contribution. By impactor will
More informationZMP Trajectory Generation for Reduced Trunk Motions of Biped Robots
ZMP Trajectory Generation for Reduced Trunk Motions of Biped Robots Jong H. Park School of Mechanical Engineering Hanyang University Seoul, 33-79, Korea email:jong.park@ieee.org Yong K. Rhee School of
More informationInternational Research Journal of Electronics and Computer Engineering Vol 1(3) Oct-Dec 2015
The PLC Based Design for the Air Compressor Control Process Miss Zahra Haghparas Electrical and electronic engineering Shiraz university of technology Shiraz, Iran f.haghparas@yahoo.com Ebrahim Abiri Associate
More informationPI control for regulating pressure inside a hypersonic wind tunnel
PI control for regulating pressure inside a hypersonic wind tunnel Sameer U. Ranade Dept of Electrical engineering, Walchand College of Engineering, Vishrambag, Sangli.416415. State- Maharshtra Email:
More informationPressure independent control valve (PICV) FLOWMATIC
Pressure independent control valve (PICV) FLOWMATIC 145 series FM 21654 003 01262/19 GB replaces dp 01262/17 GB Function The pressure independent control valve is a device composed of an automatic flow
More informationAnalysis of Pressure Rise During Internal Arc Faults in Switchgear
Analysis of Pressure Rise During Internal Arc Faults in Switchgear ASANUMA, Gaku ONCHI, Toshiyuki TOYAMA, Kentaro ABSTRACT Switchgear include devices that play an important role in operations such as electric
More informationControlling the prefeeder
Controlling the prefeeder A prefeeder is a modulating device of some kind, controlling the material flow into the belt feeder infeed. You need it for three reasons: 1. The material can not be sheared at
More information09 - Choosing /sizing a cylinder and valve
- Choosing /sizing a cylinder and valve - Pipe flow resistence - Valve sizing - Cylinder sizing LII PIPE FLOW RESISTENCE Flow rate Qn Flow rate is calculated as the volume at normal conditions ( atmospheric
More informationInternational Journal of Technical Research and Applications e-issn: , Volume 4, Issue 3 (May-June, 2016), PP.
DESIGN AND ANALYSIS OF FEED CHECK VALVE AS CONTROL VALVE USING CFD SOFTWARE R.Nikhil M.Tech Student Industrial & Production Engineering National Institute of Engineering Mysuru, Karnataka, India -570008
More informationResearch on ESC Hydraulic Control Unit Property and Pressure Estimation
Research on ESC Hydraulic Control Unit Property and Pressure Estimation Liu Wei, Ding Haitao *, and Guo Konghui State Key Libratory of Automobile Dynamic Simulation, Jilin University, Changchun 30025,
More informationAn Investigation of Liquid Injection in Refrigeration Screw Compressors
An Investigation of Liquid Injection in Refrigeration Screw Compressors Nikola Stosic, Ahmed Kovacevic and Ian K. Smith Centre for Positive Displacement Compressor Technology, City University, London EC1V
More informationCapacity Modulation of Linear Compressor for Household Refrigerator
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 2004 Capacity Modulation of Linear Compressor for Household Refrigerator Kyun Bum Heo LG
More informationBody Stabilization of PDW toward Humanoid Walking
Body Stabilization of PDW toward Humanoid Walking Masaki Haruna, Masaki Ogino, Koh Hosoda, Minoru Asada Dept. of Adaptive Machine Systems, Osaka University, Suita, Osaka, 565-0871, Japan ABSTRACT Passive
More informationMANUAL KPS Pressure Control Valve
TetraTec Instruments GmbH Gewerbestrasse 8 71144 Steinenbronn Deutschland E-Mail: info@tetratec.de Tel.: 07157/5387-0 Fax: 07157/5387-10 MANUAL Pressure Control Valve *** VERSION 1.0 *** Update: 17.11.2006
More informationTime-Delay Electropneumatic Applications
Exercise 3-4 EXERCISE OBJECTIVE & & & To introduce time delays; To describe the operation of a time-delay valve; To describe the operation of a time-delay relay. DISCUSSION Time-Delays Time delays are
More informationHOW FAST/FAR DOES FLY LINE FALL? N. Perkins of the University of Michigan, March 2003
HOW FAST/FAR DOES FLY LINE FALL? N. Perkins of the University of Michigan, March 003 This report summarizes a simple model for the free fall dynamics of a length of fly line. The line is assumed to remain
More informationFLUID POWER FLUID POWER EQUIPMENT TUTORIAL OTHER FLUID POWER VALVES. This work covers part of outcome 2 of the Edexcel standard module:
FLUID POWER FLUID POWER EQUIPMENT TUTORIAL OTHER FLUID POWER VALVES This work covers part of outcome 2 of the Edexcel standard module: UNIT 21746P APPLIED PNEUMATICS AND HYDRAULICS The material needed
More informationLab 1c Isentropic Blow-down Process and Discharge Coefficient
058:080 Experimental Engineering Lab 1c Isentropic Blow-down Process and Discharge Coefficient OBJECTIVES - To study the transient discharge of a rigid pressurized tank; To determine the discharge coefficients
More informationProject Title: Pneumatic Exercise Machine
EEL 4924 Electrical Engineering Design (Senior Design) Preliminary Design Report 27 January 2011 Project Title: Pneumatic Exercise Machine Team Members: Name: Gino Tozzi Name: Seok Hyun (John) Yun Email:
More informationDIAGNOSTICS OF IMPULSE LINE BLOCKAGE WITH A MULTI-SENSING DIFFERENTIAL PRESSURE TRANSMITTER AT THE AIR LINE
DIAGNOSTICS OF IMPULSE LINE BLOCKAGE WITH A MULTI-SENSING DIFFERENTIAL PRESSURE TRANSMITTER AT THE AIR LINE Akira Uehara, Jyun-ichi Eino, Takumi Hashizume 3, Tetsuya Wakui 3, Nobuo Miyaji 4, Yoshitaka
More informationControlling Walking Behavior of Passive Dynamic Walker utilizing Passive Joint Compliance
Controlling Walking Behavior of Passive Dynamic Walker utilizing Passive Joint Compliance Takashi TAKUMA, Koh HOSODA Department of Adaptive Machine Systems, Graduate School of Engineering Osaka University
More informationMeasuring range Δp (span = 100%) Pa
4.4/ RLE 5: Volume-flow controller, continuous How energy efficiency is improved Enables demand-led volume flow control for the optimisation of energy consumption in ventilation systems. Areas of application
More informationCHAPTER 3 : AIR COMPRESSOR
CHAPTER 3 : AIR COMPRESSOR Robotic & Automation Department FACULTY OF MANUFACTURING ENGINEERING, UTeM Learning Objectives Identify types of compressors available Calculate air capacity rating of compressor
More informationDigital Computer Simulation of a Reciprocating Compressor-A Simplified Analysis
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 1972 Digital Computer Simulation of a Reciprocating Compressor-A Simplified Analysis D.
More informationMATHEMATICAL MODELING OF PERFORMANCE OF A LIQUD PISTON COMPRESSOR
9. Pompa Vana Kompressör Kongresi 5-7 Mayıs 2016, İstanbul MATHEMATICAL MODELING OF PERFORMANCE OF A LIQUD PISTON COMPRESSOR Süleyman Doğan Öner Email: oner@ug.bilkent.edu.tr İbrahim Nasuh Yıldıran Email:
More informationPressure on Demand. Air Pressure Amplifiers
Pressure on Demand Air Pressure Amplifiers Introduction Haskel air pressure amplifiers offer the most comprehensive range in the industry combining simple principles of operation with rugged construction
More informationTechnical Data Sheet MF010-O-LC
Technical Data Sheet MF010-O-LC - 1 - 1. Properties The oxygen measuring system MF010-O-LC determines the oxygen content in gas mixtures up to a temperature of 250 C. It is particularly suitable for the
More informationAIAA Brush Seal Performance Evaluation. P. F. Crudgington Cross Manufacturing Co. Ltd. Devizes, ENGLAND
AIAA 98-3172 Brush Seal Performance Evaluation P. F. Crudgington Cross Manufacturing Co. Ltd. Devizes, ENGLAND BRUSH SEAL PERFORMANCE EVALUATION AIAA-98-3172 P. F. Crudgington Cross Manufacturing Co. Ltd
More informationKeywords: Flap controls, Redundancy, Dynamic simulation, Failure
27 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES REDUNDANT HYDRAULIC SECONDARY FLIGHT CONTROL SYSTEMS BEHAVIOR IN FAILURE CONDITIONS Lorenzo Borello, Giuseppe Villero, Matteo Dalla Vedova Department
More informationGP1 & GP2. Electropneumatic Regulators FOR PRESSURE CONTROL TO 1,000 PSI
GP1 & GP2 Electropneumatic Regulators FOR PRESSURE CONTROL TO 1, PSI GP1 & GP2 Functional Description The GP series control valve is an electronic pressure regulator designed to precisely control the pressure
More informationInternational Journal of Advance Engineering and Research Development DESIGN CALCULATIONS TO EVALUATE PERFORMANCE PARAMETERS OF COMPRESSOR VALVE
Scientific Journal of Impact Factor (SJIF): 4.72 International Journal of Advance Engineering and Research Development Volume 4, Issue 7, July -2017 e-issn (O): 2348-4470 p-issn (P): 2348-6406 DESIGN CALCULATIONS
More informationExercise 8. Closed-Loop Pressure Control, Proportional-Plus-Integral Mode EXERCISE OBJECTIVE
Exercise 8 Closed-Loop Pressure Control, EXERCISE OBJECTIVE To understand open and closed-loop pressure control; To learn how to sense the pressure in a pneumatic circuit; To control the pressure in a
More informationThe exit velocity of a compressed air cannon
The exit velocity of a compressed air cannon Z. J. Rohrbach, T. R. Buresh, and M. J. Madsen Department of Physics, Wabash College, Crawfordsville, IN 47933 (Dated: June 16, 2011) Abstract AirCannonPlans.Com
More informationFlow in a shock tube
Flow in a shock tube April 30, 05 Summary In the lab the shock Mach number as well as the Mach number downstream the moving shock are determined for different pressure ratios between the high and low pressure
More informationDigital Level Control One and Two Loops Proportional and Integral Control Single-Loop and Cascade Control
Digital Level Control One and Two Loops Proportional and Integral Control Single-Loop and Cascade Control Introduction This experiment offers a look into the broad field of process control. This area of
More informationExperimental Analysis on Vortex Tube Refrigerator Using Different Conical Valve Angles
International Journal of Engineering Research and Development e-issn: 7-067X, p-issn: 7-00X, www.ijerd.com Volume 3, Issue 4 (August ), PP. 33-39 Experimental Analysis on Vortex Tube Refrigerator Using
More informationCharacterizers for control loops
Characterizers for control loops By: F. G. Shinskey (May 1999) Introduction Commercial controllers such as the PID series (proportional, integral, derivative, and their combinations) are linear devices
More informationISOLATION OF NON-HYDROSTATIC REGIONS WITHIN A BASIN
ISOLATION OF NON-HYDROSTATIC REGIONS WITHIN A BASIN Bridget M. Wadzuk 1 (Member, ASCE) and Ben R. Hodges 2 (Member, ASCE) ABSTRACT Modeling of dynamic pressure appears necessary to achieve a more robust
More informationPREDICTION OF TOTAL PRESSURE CHARACTERISTICS IN THE SETTLING CHAMBER OF A SUPERSONIC BLOWDOWN WIND TUNNEL
PREDICTION OF TOTAL PRESSURE CHARACTERISTICS IN THE SETTLING CHAMBER OF A SUPERSONIC BLOWDOWN WIND TUNNEL S R Bhoi and G K Suryanarayana National Trisonic Aerodynamic Facilities, National Aerospace Laboratories,
More informationUnit 55: Instrumentation and Control Principles
Unit 55: Instrumentation and Control Principles Unit code: J/601/1417 QCF level: 4 Credit value: 15 OUTCOME 2 PROCESS CONTROL SYSTEMS AND CONTROLLERS 2 Understand process control systems and controllers
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 9, 2010 http://acousticalsociety.org/ 159th Meeting Acoustical Society of America/NOISE-CON 2010 Baltimore, Maryland 19-23 April 2010 Session 1pBB: Biomedical
More informationLecture 19 PRESSURE-CONTROL VALVES [CONTINUED]
Lecture 19 PRESSURE-CONTROL VLVES [CONTINUED] 1.5 Counterbalance Valve Schematic diagram of counterbalance valve is shown in Fig. 1.14. These normally closed valves are primarily used to maintain a back
More informationNoise Characteristics Of A Check Valve Installed In R22 And R410A Scroll Compressors
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 22 Noise Characteristics Of A Check Valve Installed In R22 And R41A Scroll Compressors M.
More informationMitos Fluika Pressure and Vacuum Pumps Datasheet
Unit 1, Anglian Business Park, Orchard Road, Royston, Hertfordshire, SG8 5TW, UK T: +44 (0)1763 242491 F: +44 (0)1763 246125 E: sales@dolomite-microfluidics.com W: www.dolomite-microfluidics.com Dolomite
More informationExercise 3. Power Versus Wind Speed EXERCISE OBJECTIVE DISCUSSION OUTLINE. Air density DISCUSSION
Exercise 3 Power Versus Wind Speed EXERCISE OBJECTIVE When you have completed this exercise, you will know how to calculate the power contained in the wind, and how wind power varies with wind speed. You
More informationBasic Pneumatics. Module 8: Pressure control valves. Academic Services PREPARED BY. April 2012
Basic Pneumatics Module 8: Pressure control valves PREPARED BY Academic Services April 2012 Applied Technology High Schools, 2012 Module 8: Pressure control valves Module Objectives After the completion
More informationHardware Triaxial and Consolidation Testing Systems Pressure Measurement and Control
25 GDS Helpsheet Hardware Triaxial and Consolidation Testing Systems Pressure Measurement and Control World Leaders in Computer Controlled Testing Systems for Geotechnical Engineers and Geologists 1. Digital
More informationSimple Set. Pressure Independent Control Valves 2 Way 1/2-2
The Bray Simple Set is a threaded pressure independent control (PIC) valve designed for a wide variety of hot water and chilled water control applications. The SS Series combines high rangeability control
More informationBubble Elimination Device in Hydraulic Systems
Bubble Elimination Device in Hydraulic Systems Ryushi SUZUKI 1, Yutaka TANAKA 2, Shinichi YOKOTA 3 1 President, Opus Corp. 6-5-2 Todoroki, Setagayaku, Tokyo 158, Japan 2 Associate Professor, Department
More informationExperimental Modeling and Control of Pneumatic Cylinders for Robotic Applications
Experimental Modeling and Control of Pneumatic Cylinders for Robotic Applications Winnie Ngo Mechanical Engineering City College of New York 160 Convent Ave New York, NY 10031 USA Milwaukee School of Engineering
More informationImprovement of the Volumetric and Isentropic Efficiency Due to Modifications of the Suction Chamber
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 2008 Improvement of the Volumetric and Isentropic Efficiency Due to Modifications of the
More informationCHAPTER 3 AUTOMOTIVE AIR COMPRESSOR
30 CHAPTER 3 AUTOMOTIVE AIR COMPRESSOR 3.1 INTRODUCTION A machine providing air at a high pressure is called as an air compressor. Air compressors have been used in industry for well over 100 years because
More informationAir Cylinders Drive System Full Stroke Time & Stroke End Velocity
Full Time & End Velocity Ho to Read the Graph This graph shos the full stroke time and stroke hen a cylinder drive system is composed of the As the graph shon belo, various load ratio and full stroke time
More information(Refer Slide Time: 0:26)
Fundamentals of Industrial Oil Hydraulics and Pneumatics By Professor R. Maiti Department of Mechanical Engineering Indian Institute of Technology, Kharagpur Module03 Lecture08 Different Types of Valves-
More information1502. The effect of mechanism design on the performance of a quadruped walking machine
1502. The effect of mechanism design on the performance of a quadruped walking machine Fu-Chen Chen 1, Shang-Chen Wu 2, Yung-Cheng Chen 3 Department of Mechanical Engineering, Kun Shan University, Tainan
More informationThe Discussion of this exercise covers the following points:
Exercise 3-2 Orifice Plates EXERCISE OBJECTIVE In this exercise, you will study how differential pressure flowmeters operate. You will describe the relationship between the flow rate and the pressure drop
More informationYasuyuki Hirose 1. Abstract
Study on Tsunami force for PC box girder Yasuyuki Hirose 1 Abstract In this study, a waterway experiment was performed in order to understand the influence of tsunami forms on tsunami forces acting on
More informationAuto-Zero Calibration Technique for Pressure Sensors
Auto-Zero Calibration Technique for Pressure Sensors A Technical Note 1.0 INTRODUCTION This technical note describes how to implement Auto-Zero, a calibration technique for pressure sensors based on sampling
More informationBasic Hydraulics. Module 4: Flow Control Valves & Pressure Relief Valves. Academic Services PREPARED BY. January 2012
Basic Hydraulics Module 4: Flow Control Valves & Pressure Relief Valves PREPARED BY Academic Services January 2012 Applied Technology High Schools, 2011 ATM 1122 Basic Hydraulics Module 4: Flow control
More informationUsing PV Diagram Synchronized With the Valve Functioning to Increase the Efficiency on the Reciprocating Hermetic Compressors
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 21 Using PV Diagram Synchronized With the Valve Functioning to Increase the Efficiency on
More informationChapter 10: Bidirectional Flow Controls
Chapter 10: Bidirectional Flow Controls Objectives Learn about the patented, bidirectional flow control valves. Understand how the flow force affects the performance of the ZL70-36. Learn why there is
More informationMODELING OF THERMAL BEHAVIOR INSIDE A BUBBLE
CAV2001:sessionB6.002 1 MODEING OF THERMA BEHAVIOR INSIDE A BUBBE Boonchai ERTNUWAT *, Kazuyasu SUGIYAMA ** and Yoichiro MATSUMOTO *** *, ***Dept. of Mechanical Engineering, The University of Tokyo, Tokyo,
More informationFluid Flow. Link. Flow» P 1 P 2 Figure 1. Flow Model
Fluid Flow Equipment: Water reservoir, output tubes of various dimensions (length, diameter), beaker, electronic scale for each table. Computer and Logger Pro software. Lots of ice.temperature probe on
More informationVibration Analysis and Test of Backup Roll in Temper Mill
Sensors & Transducers 2013 by IFSA http://www.sensorsportal.com Vibration Analysis and Test of Backup Roll in Temper Mill Yuanmin Xie College of Machinery and Automation, Wuhan University of Science and
More informationTutorial. BOSfluids. Relief valve
Tutorial Relief valve The Relief valve tutorial describes the theory and modeling process of a pressure relief valve or safety valve. It covers the algorithm BOSfluids uses to model the valve and a worked
More information67. Sectional normalization and recognization on the PV-Diagram of reciprocating compressor
67. Sectional normalization and recognization on the PV-Diagram of reciprocating compressor Jin-dong Wang 1, Yi-qi Gao 2, Hai-yang Zhao 3, Rui Cong 4 School of Mechanical Science and Engineering, Northeast
More informationExercise 2-2. Second-Order Interacting Processes EXERCISE OBJECTIVE DISCUSSION OUTLINE. The actual setup DISCUSSION
Exercise 2-2 Second-Order Interacting Processes EXERCISE OBJECTIVE Familiarize yourself with second-order interacting processes and experiment with the finer points of controller tuning to gain a deeper
More informationOptimizing Compressed Air Storage for Energy Efficiency
University of Dayton ecommons Mechanical and Aerospace Engineering Faculty Publications Department of Mechanical and Aerospace Engineering 4-2011 Optimizing Compressed Air Storage for Energy Efficiency
More informationEnd of Chapter Exercises
End of Chapter Exercises Exercises 1 12 are conceptual questions that are designed to see if you have understood the main concepts of the chapter. 1. While on an airplane, you take a drink from your water
More informationMotion Control of a Bipedal Walking Robot
Motion Control of a Bipedal Walking Robot Lai Wei Ying, Tang Howe Hing, Mohamed bin Hussein Faculty of Mechanical Engineering Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia. Wylai2@live.my
More informationInfluence of Volumetric Displacement and Aspect Ratio on the Performance Metrics of the Rotating Spool Compressor
Influence of Volumetric Displacement and Aspect Ratio on the Performance Metrics of the Rotating Spool Compressor Craig Bradshaw, PhD Manager of Research and Development, Torad Engineering Greg Kemp, Torad
More informationComponents for air preparation and pressure adjustment. OUT port position ( ) connected Rear side. of IN port. Air tank. directly.
Components preparation and pressure adjustment ABP Overview ABP is a component that enables boosting by s only up to twice primary pressure (.0MPa max.) in combination with using air tank but not using
More informationFail Operational Controls for an Independent Metering Valve
Group 14 - System Intergration and Safety Paper 14-3 465 Fail Operational Controls for an Independent Metering Valve Michael Rannow Eaton Corporation, 7945 Wallace Rd., Eden Prairie, MN, 55347, email:
More informationA Research on the Airflow Efficiency Analysis according to the Variation of the Geometry Tolerance of the Sirocco Fan Cut-off for Air Purifier
A Research on the Airflow Efficiency Analysis according to the Variation of the Geometry Tolerance of the Sirocco Fan Cut-off for Air Purifier Jeon-gi Lee*, Choul-jun Choi*, Nam-su Kwak*, Su-sang Park*
More informationFAULT DIAGNOSIS IN DEAERATOR USING FUZZY LOGIC
Fault diagnosis in deaerator using fuzzy logic 19 FAULT DIAGNOSIS IN DEAERATOR USING FUZZY LOGIC S.Srinivasan 1), P.Kanagasabapathy 1), N.Selvaganesan 2) 1) Department of Instrumentation Engineering, MIT
More informationCFD Simulation and Experimental Validation of a Diaphragm Pressure Wave Generator
CFD Simulation and Experimental Validation of a Diaphragm Pressure Wave Generator T. Huang 1, A. Caughley 2, R. Young 2 and V. Chamritski 1 1 HTS-110 Ltd Lower Hutt, New Zealand 2 Industrial Research Ltd
More informationModulating Valves for Atmospheric, Infrared, and Direct Fired Burners
BULLETIN MT2035-07/05 Modulating Valves for Atmospheric, Infrared, and Direct Fired Burners M/MR Series M411, M511, M611 M420, M520, M620, MR410, MR510, MR610 MR212D, MR212E, MR212G and MR212J (Flanged),
More informationLQG Based Robust Tracking Control of Blood Gases during Extracorporeal Membrane Oxygenation
2011 American Control Conference on O'Farrell Street, San Francisco, CA, USA June 29 - July 01, 2011 LQG Based Robust Tracking Control of Blood Gases during Extracorporeal Membrane Oxygenation David J.
More informationLOW PRESSURE EFFUSION OF GASES adapted by Luke Hanley and Mike Trenary
ADH 1/7/014 LOW PRESSURE EFFUSION OF GASES adapted by Luke Hanley and Mike Trenary This experiment will introduce you to the kinetic properties of low-pressure gases. You will make observations on the
More informationMEASUREMENT OF GAS DISCHARGE COEFFICIENT
MEASUREMENT OF GAS DISCHARGE COEFFICIENT Ilona Pasková, Ondřej Novák, Václav Koza RWE GasNet, ilona.paskova@rwe.cz ICT Prague, Department of gas, coke and air protection, ondrej.novak@vscht.cz, vaclav.koza@vscht.cz
More informationE. Agu, M. Kasperski Ruhr-University Bochum Department of Civil and Environmental Engineering Sciences
EACWE 5 Florence, Italy 19 th 23 rd July 29 Flying Sphere image Museo Ideale L. Da Vinci Chasing gust fronts - wind measurements at the airport Munich, Germany E. Agu, M. Kasperski Ruhr-University Bochum
More informationBecker Precision Equipment
Becker Precision Equipment VRP-B-CH Series Valve Regulation Pilot VRP-B-CH Valve Regulator Pilot Provides Low-Bleed Pressure Control When Combined with Double-Acting Pneumatic Control Valve Actuators Description
More informationApplied Fluid Mechanics
Applied Fluid Mechanics 1. The Nature of Fluid and the Study of Fluid Mechanics 2. Viscosity of Fluid 3. Pressure Measurement 4. Forces Due to Static Fluid 5. Buoyancy and Stability 6. Flow of Fluid and
More informationLECTURE 20 FLOW CONTROL VAVLES SELF EVALUATION QUESTIONS AND ANSWERS
LECTURE 20 FLOW CONTROL VAVLES SELF EVALUATION QUESTIONS AND ANSWERS 1: A cylinder has to exert a forward thrust of 150 kn and a reverse thrust of 15 kn. The effects of using various methods of regulating
More information(AS AT 31 st MARCH, 2002)
ACACA PROTOCOL 2000 (AS AT 31 st MARCH, 2002) ACACA PROTOCOL 2000 INCLUDES (A) CODE OF PRACTICE FOR MANUFACTURERS AND/OR SUPPLIERS OF COMMERCIAL AIR COMPRESSORS AND METHOD FOR DETERMINING (B) RECIPROCATING
More information