Compressed air leakage accounts for up to 42% of electrical energy loss on a typical mine compressed air system. By using underground control valves it is possible to reduce the amount of air leakage. Underground valve control was successfully implemented in a South African mine. The project implementation and achieved results are documented in this study. The implementation of underground control valves initially requires a large capital investment. In this study the electrical and financial savings realised by underground valve control and surface valve control were calculated. The payback periods for each control strategy were determined and compared. It was determined that underground valve control can realise up to 40% higher electrical savings than surface control. Depending on the size of the mine and due to the large initial investment, the payback period for an underground valve control system can be up to six times longer than that of a surface control system. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Compressed air leakage accounts for up to 42% of electrical energy loss on a typical mine compressed air system. By using underground control valves it is possible to reduce the amount of air leakage. Underground valve control was successfully implemented in a South African mine. The project implementation and achieved results are documented in this study. The implementation of underground control valves initially requires a large capital investment. In this study the electrical and financial savings realised by underground valve control and surface valve control were calculated. The payback periods for each control strategy were determined and compared. It was determined that underground valve control can realise up to 40% higher electrical savings than surface control. Depending on the size of the mine and due to the large initial investment, the payback period for an underground valve control system can be up to six times longer than that of a surface control system. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

This paper studies a method for active electrohydraulic force compensation in industrial scale high power applications. A valve controlled cylinder moves a mass using the force of inertia to compensate for the reaction forces of an industrial process. Two strategies for force compensation are developed and investigated in a 160 ton clamping unit of an injection moulding machine to significantly reduce the excitation. Results of the different strategies are shown and evaluated. Advantages and drawbacks of the developed electrohydraulic force compensation are discussed.

Hybrid powertrains that use compressed air to help power a vehicle could dramatically improve the fuel economy, particularly in cities and urban areas where the traffic conditions involve a lot of starts and stops. In such conditions, a large amount of fuel is needed to accelerate the vehicle, and much of this is converted to heat in brake friction during decelerations. Capturing, storing and reusing this braking energy to produce additional power can therefore improve fuel efficiency. In this study, three approaches towards air hybrid powertrains are proposed and analyzed. In the first approach, an energy recovery valve or two shut-off valves connected to a convenient access hole on the engine cylinder is proposed to enable the cylinder to operate as a regenerative compressor and/or expander when required. In the second approach, one of the exhaust valves in an engine equipped with a Fully Variable Valve Actuation (FVVA) system is pneumatically or hydraulically operated as a dedicated gas transfer valve connected to an air reservoir. The third approach combines the advantages of the conventional valvetrain’s simplicity with emerging production technologies. In order to achieve this, two well established technologies are used in addition to valve deactivation; Variable Valve Timing (VVT) and/or Cam Profile Switching (CPS). Provided that a conventional, camshaft-operated variable valvetrain is used, the need of adopting fully variable valve actuation is eliminated and thus only minor modifications to the engine architecture are required. The aforementioned concepts are described in details. Some basic principles of their operation are also discussed in order to provide a better understanding on how fuel economy is achieved by means of engine hybridization and regenerative braking. Both experimental and computational results are presented and compared. Finally, a vehicle and driveline model, which simulates the operation of a typical passenger vehicle in urban driving conditions and predicts the efficiency of the energy regeneration, has been set up and used to study the effects of the application of each air hybrid concept on the vehicle’s energy usage throughout the New European Driving Cycle (NEDC) and the 10-15 driving cycle. The results have shown that each concept involves the optimization of valve timing for the best regenerative energy recovery and its subsequent usage. For the modelled vehicle, it has been shown that any of the three concept engines is capable of providing more braking power than needed during every deceleration and braking process, especially throughout the urban driving part of each cycle. The recovered braking energy in the form of compressed air has proved to be always sufficient to start the engine, if stop-and-start engine operation strategy is to be adopted.

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This report is going to investigate the possibility to save energy by converting a valve opening mechanism in a waste disposal system from a pneumatic system to an electric system. To power the system, which mainly consists of an electric actuator and a valve control module, a solar panel system was designed. The valve system was controlled by the lightweight messaging protocol MQTT. To be able to choose an electric actuator the needed force was measured and data regarding maximal stroke was taken from the data sheet of the existing setup. For developing an optimal solar panel system a program was written in Google Spreadsheet. The program takes input regarding power, cycles, solar panel system specifications and environmental factors. The output from the program is energy consumption for the system, specification for solar charger, solar panel setup and charge data. The result was that the solar panel system needed to consists of four 12 V VRLA batteries with a capacity of 90 Ah each and four solar panels with a rated power of 300 W each. The solar charger must be able to handle 900 W and provide an output current of 25,5 A to fulfil the demands. The new electric actuator will consume four times less energy than the old pneumatic actuator. Most of the energy savings are consequences of reduced energy consumption at idle of the system. A demonstarator was built to test the system. / Den här rapporten kommer att undersöka möjligheten att spara energi genom att konvertera ett ventilöppningsmekanism i ett avfallshanteringssystem från ett pneumatiskt system till ett elektriskt system. För att driva systemet, som främst består av en elektrisk aktuator och en ventil styrenhet, ska ett solcellssystem designas. Ventilsystemet ska styras med hjälp lättviktsmeddelandeprotokollet MQTT. För att kunna välja en aktuator mättes den behövda kraften och data angående maximal slaglängd togs från databladet på den nuvarande konstruktionen. För att utveckla ett optimalt solcellssystem skrevs ett program i Google Kalkylark. Programmet använder energi, cykler, solcellssystem och miljöfaktorer som indata. Som utdata ges energiförbrukning hos systemet, specifikation för solcellsregulator, solpaneler och laddningsdata. Resultatet var att det solcellssystem som behövs bestå av fyra 12 V VRLA batterier med en kapacitet på 90 Ah var och fyra solpaneler med en nominell effekt på 300 W vardera. Solcellssregulatorn behöver kunna hantera 900 W och generera en ström på 25,5 A. Den nya elektriska aktuatorn kommer förbruka fyra gånger så lite energi jämfört med den gamla pneumatiska aktuatorn. Den största delen av energibesparingarna är en konsekvens av minskad energiförbrukning av systemet i vila. En prototyp byggdes för att testa systemet.

Water is an essential resource for basic human survival, but today several cities and people lack access to both reliable and clean water. Dar es Salaam in Tanzania is undergoing a rapid population growth and need to improve their current water delivery system in order to provide water to the city’s inhabitants. This report’s objective is to examine if Dar es Salaam Water and Sewerage Authority (DAWASA) manual water valve operation is improved with the usage of remote-controlled valves instead. The remote-controlled system will consequently be evaluated and compared against the manually controlled valves. In order to obtain necessary data for this study interviews and field trips were conducted at DAWASA as well as at the local market at Kariakoo. Additionally, information has also been gathered from the collaboration partners at College of Information and Communication Technologies (CoICT). The results provided information that a remote-controlled system could, in the measured reference area of 52 km of water pipes, save up to 900 U.S dollar monthly and 46 m3 of water daily for DAWASA. These savings would consequently contribute to an increase in resources which leads to further improvements to the current water distribution system. Because, today’s system is in need of a development in order to sufficiently provide potable water to the city. The remote-controlled system could also help to reduce the spread of waterborne diseases, destruction of roads and create a more reliable source of water since the water valves would be regulated more efficiently. A remote-controlled system would however need a sufficient amount of funding in order to be installed, but is both simpler to install and a more feasible solution compared to other alternatives. For these reasons, the designed system is concluded to be a more effective, sustainable and economical feasible solution for handling and managing the outdated valves.

This paper studies a method for active electrohydraulic force compensation in industrial scale high power applications. A valve controlled cylinder moves a mass using the force of inertia to compensate for the reaction forces of an industrial process. Two strategies for force compensation are developed and investigated in a 160 ton clamping unit of an injection moulding machine to significantly reduce the excitation. Results of the different strategies are shown and evaluated. Advantages and drawbacks of the developed electrohydraulic force compensation are discussed.

An industrial control valve has been designed by Eaton (AxisPro® valve). The servo performance valve has onboard electronics that features external and internal sensor interfaces, advanced control modes and network capability. Advanced control modes are implement in the valves firmware. With the help of the white space it is possilbe to execute custom code directly on the valve that interact with these controls. Small OEM applications, like rubber moulding machines, benefit from the comination of build in controls and custom code, to provide adaptations for their special machines.

In this thesis study, a valveless hydraulic servo system controlled by two pumps is investigated and its performance characteristics are compared with a conventional valve controlled system both experimentally and analytically. The two control techniques are applied on the position control of a single rod linear actuator. In the valve controlled system, the flow rate through the actuator is regulated with a servovalve / whereas in the pump controlled system, two variable speed pumps driven by servomotors regulate the flow rate according to the needs of the system, thus eliminating the valve losses. To understand the dynamic behaviors of two systems, the order of the differential equations defining the system dynamics of the both systems are reduced by using the fact that the dynamic pressure changes in the hydraulic cylinder chambers become linearly dependent on leakage coefficients and cylinder chamber volumes above and below some prescribed cut off frequencies. Thus the open loop speed response of the pump controlled and valve controlled systems are defined by v second order transfer functions. The two systems are modeled in MATLAB Simulink environment and the assumptions are validated. For the position control of the single rod hydraulic actuator, a linear state feedback control scheme is applied. Its state feedback gains are determined by using the linear and linearized reduced order dynamic system equations. A linear Kalman filter for pump controlled system and an unscented Kalman filter for valve controlled system are designed for estimation and filtering purposes. The dynamic performances of both systems are investigated on an experimental test set up developed by conducting open loop and closed loop frequency response and step response tests. MATLAB Real Time Windows Target (RTWT) module is used in the tests for application purposes.