Hydraulic Bench Apparatus

The Basic Hydraulic Bench permits a varied experimental cross-section in the fundamentals of fluid mechanics. The unit provides the basic equipment for individual experiments, the supply of water in the closed circuit; the determination of volumetric flow rate and the positioning of the experimental unit on the working surface of the base module and the collection of dripping water.
The closed water circuit consists of the underlying storage tank with a powerful centrifugal pump and the measuring tank arranged above, in which the returning water is collected.
The measuring tank is stepped, for larger and smaller volumetric flow rates. A measuring beaker is used for very small volumetric flow rates. The volumetric flow rates are measured using a stopwatch.
The top work surface enables the various experimental units to be easily and safely positioned. A small flume is integrated in the work surface, in which experiments with weirs are conducted.


Flow Over Weirs

Using the supplied weir plates, the measurement of flow rate in open channels can be investigated. They are used together with the hydraulic bench. Water is fed from the hydraulic bench into a section of channel, the water then flows over the weir into the volumetric tank and back to the sump tank. A weir with a V notch (Thomson weir) and a weir with a rectangular notch are provided for the investigations.
A depth gauge for the determination of the weir head is included.


Metacentric Height Apparatus

Determination and analysis of the stability of floating bodies, such as ships, rafts and pontoons, is important throughout many branches of engineering. This experiment allows students to determine the stability of a pontoon with its centre of gravity at various heights. They can then compare this to predictions calculated from theory.
The experiment consists of a rectangular pontoon floating in water made of plastic. The pontoon has a plastic sail with five rows of slots. These rows are at equally spaced heights on the sail.
The slots are equally spaced around the centre line. To change the centre of gravity and the tilt (list) angle of the pontoon, students fit an adjustable weight into one of the slots. A plumb line from the top centre of the sail and a scale below the base indicate the tilt angle. Students obtain fore and aft balance by positioning two small magnetic trim weights on the bottom of the pontoon.


Hydrostatic Pressure Apparatus

This product allows students to measure the moment due to the fluid (hydrostatic) thrust on a fully or partially submerged plane. The plane works in either a vertical or inclined (angled) position. Students then compare their measurements with theoretical analysis. The equipment consists of a vertical panel that holds a clear plastic quadrant, to which students add water. The quadrant has lines to help students keep the plane in a vertical or angled position.
The cylindrical sides of the quadrant have their central axis coincidental with the moment measurement axis. The total fluid pressures on these curved surfaces therefore exert no moment about this pivot. Therefore, the moment is only due to the fluid pressure on the plane test surface.
Students measure this moment using weights suspended from a level arm. A scale on the panel of the apparatus shows the head of water.
To perform experiments, students level the apparatus using its levelling feet and spirit (bubble) level. They decide whether to test either a vertical or inclined plane. They then initially balance the quadrant tank using one of the weight hangers and the smaller trimming tank. They take results by balancing incremental weights on the hanger with known quantities of water. They then use the results to calculate the equivalent moment of force (M) or hydrostatic thrust. Students note the relationship between the moment and the water height (h).
The equipment includes non-toxic water dye to help students see the water levels more clearly and a syringe for accurate addition or removal of small amounts of water. Supplied with comprehensive user guide


Orifice & Free Jet Flow Apparatus

A plexiglass cylinder is equipped with an adjustable overflow and scale which enables the height of the water column to be set and read accurately.
4 types of outlet nozzle can be compared. The trajectory of the jet can be traced using adjustable probes and recorded on a white panel. The water supply is provided either from the laboratory mains or using the Hydraulic Bench.


Dead Weight Apparatus

The unit consists of a precision machined piston and cylinder assembly mounted on leveling screws. A bourdon gauge is supplied for calibration the weights supplied are added to the upper end of the piston rod which is rotated to minimize friction effects the gauge is thus subject to known pressure which may be compared with the gauge reading and an error area drawn.
Dead Weight Pressure Calibrator apparatus consists of a precision machined piston and cylinder assembly mounted on leveling screws. A Bourdon gauge is supplied for calibration. The weights supplied are added to the upper end of the piston rod which is rotated to minimize friction effects. The gauge is thus subject to known pressures which may be compared with the gauge readings and an error curve drawn.


Impact of Jet Apparatus

The unit comprises a Plexiglas tank in which a water jet discharged from a nozzle hits a surface and is deflected. 4 different test shapes with the following deflection angles are included: Flat plate, hemisphere 180°, angled plate 30°, cone 120°. The impact forces at the deflector are measured using scales loaded with weights.
The water supply is provided either from the laboratory mains or using the Hydraulic Bench (closed water circuit).


Bernoulli's Theorem Apparatus

Bernoulli's Theorem Apparatus consists of a classical Venturi made of clear acrylic. A series of wall tappings allow measurement of the static pressure distribution along the converging duct, while a total head tube is provided to traverse along the centre line of the test section. These tappings are connected to a manometer bank incorporating a manifold with air bleed valve. Pressurization of the manometers is facilitated by a hand pump.
This unit has been designed to be used with a Hydraulics Bench for students to study the characteristics of flow through both converging and diverging sections. During the experiment, water is fed through a hose connector and students may control the flow rate of the water by adjusting a flow regulator valve at the outlet of the test section. The venturi can be demonstrated as a means of flow measurement and the discharge coefficient can be determined. This test section can be used to demonstrate those circumstances to which Bernoulli's Theorem may be applied as well as in other circumstances where the theorem is not sufficient to describe the fluid behavior.
The unit is mounted on a base board which is to be placed on top of the Hydraulic Bench. This base board has four adjustable feet to level the apparatus. The main test section is an accurately machined acrylic venturi of varying circular cross section. It is provided with a number of side hole pressure tappings, which are connected to the manometer tubes on the rig. These tappings allow the measurement of static pressure head simultaneously at each of 8 sections. The tapping positions and the test section diameters are shown in Appendix A. The test section incorporates two unions, one at either end, to facilitate reversal for convergent or divergent testing.
A hypodermic tube, the total pressure head probe, is provided which may be positioned to read the total pressure head at any section of the duct. This total pressure head probe may be moved after slacking the gland nut; this nut should be re-tightened by hand after adjustment. An additional tapping is provided to facilitate setting up. All eight pressure tapings are connected to a bank of pressurized manometer tubes. Pressurization of the manometers is facilitated by connecting any hand pump to the inlet valve on the manometer manifold. The unit is connected to the hydraulic bench using flexible hoses. The hoses and the connections are equipped with rapid action couplings. A flow control valve is incorporated downstream of the test section. Flow rate and pressure in the apparatus may be varied independently by adjustment of the flow control valve and the bench supply control valve. Please familiarize with the unit before operating the unit.


Orifice Discharge Apparatus

The water drains vertically from a transparent supply tank through a nozzle due to the hydrostatic pressure. The velocity of the jet can be measured with a Pitot tube and a U-tube manometer.
The jet diameter is measured with a micrometer. 5 easy to interchange nozzles are included. The water level can be set precisely using an overflow. The water supply is provided either from the laboratory mains or using the Hydraulic Bench.


Osborne Reynold's Apparatus

The Osborne Reynold's Apparatus has been designed for students experiment on the laminar, transition and turbulent flow. It consists of a transparent header tank and flow visualization pipe.
The header tank is provided with a diffuser and stilling materials at the bottom to provide a constant head of water to be discharged through a bell mouth entry to the flow visualization pipe. Flow through this pipe is regulated using a control valve at the discharge end. The water flow rate through the pipe can be measured using the volumetric tank (or volumetric cylinder). Velocity of the water can therefore be determined to allow the calculation of the Reynold's Number. A dye injection system is installed on top of the header tank so that flow pattern in the pipe can be visualized.
The Osborne Reynolds Demonstration apparatus is equipped with a visualization tube for students to observe the flow condition. The rocks inside the stilling tank are to calm the inflow water so that there will not be any turbulence to interfere with the experiment. The water inlet / outlet valve and dye injector are utilized to generate the required flow.


Free and Forced Vortex Apparatus
The Free and Forced Vortex apparatus has been designed for students to experiments to produce and measure free and forced vortices.
It consists of a clear acrylic cylinder where the free vortex is generated by water discharging through an interchangeable orifice in the base of the cylinder. The resulting profile is then measured using a combined caliper and depth scale. The forced vortex is induced by a paddle rotated by jets of water at the cylinder base. The profile of the forced vortex is then determined using a series of depth gauges. Velocity at any point in the free or forced vortices may be measured using the pitot tube supplied. The apparatus is designed to be positioned on the side channels of the hydraulics bench top channel. The apparatus consists of a cylindrical vessel having two pairs of diametrically opposed inlet tubes. Overflow cut-outs ensure a constant level in the tank during experiments. A smooth outlet is centrally positioned in the base of the vessel, and a set of push-in orifices of various diameters are supplied. The 12.5mm diameter inlet tubes, which are angled at 15 degrees, impart a swirling motion to the liquid entering the vessel, and are used as entry tubes for the free vortex experiment.
The forced vortex is created by using the 9mm inlet tubes which are angled at 60 degrees to the diameter. The input from these tubes impinges on a paddle which acts as a stirrer/flow straightener. The paddle rotates on a stud mounted on a bushed plug inserted in the central orifice. A bridge piece incorporating measuring needles is used to determine the profile of the forced vortex. The needle can be travel along X and Y Axis on a pre calibrated scale so a virtually infinite position of the vortex can be drawn rather than the fixed point measurements. Velocity heads may be visualized by the insertion of pitot tube in the measuring bridge with the similar above measuring bridge.


Energy Losses in Pipe Apparatus

The experimental set-up can be used on its own or with the Hydraulic bench. A supply of water is all that is required for operation. The unit is suitable for measuring pipe friction losses for laminar and turbulent flows.
The experimental set-up is clearly laid out on a training panel. For investigations on laminar flow, a head tank is used for the water supply, whilst for turbulent flow, the supply is provided via the Basic Hydraulics Bench directly (or the water mains). The water flows through a pipe section; the flow is adjusted using reducing valves.
The connection to the required measuring device is made via pressure tappings.


Pelton Turbine Apparatus

The Apparatus of Pelton turbine mounts on the base. Pelton turbine is mounted is Stainless Steel and transparent Plexiglass Hosing. A adjustable water spear valve allow the water to leave through the nozzle and hits the buckets.
An adjustable spear valve controls the discharge by varying the diameter of the jet from the nozzle. The Hydraulic Bench supplies water to the nozzle. Water from the turbine discharges back into the base unit tank and recalculates. This demonstration Pelton Turbine is a miniature Pelton wheel with spear valve arrangement mounted on a support frame which locates on the Hydraulics Bench top channel. Mechanical output from the turbine is absorbed using a simple friction dynamometer.
Pressure at the spear valve is indicated on a remote manometer gauge. A non-contacting tachometer may be used to determine the speed of the Pelton wheel. Basic principles of the Pelton turbine may be demonstrated and with appropriate measurements, power produced and efficiency may be determined. The unit provides a simple low cost introduction to turbine performance.


Francis Turbine Apparatus

Water turbines are turbo machines utilizing water power. The Francis turbine is part of the reaction turbines which convert the pressure energy of the water into kinetic energy in the control device and in the impeller. The water is fed in the control device by means of a spiral tube. The flowing water is accelerated in the control device by the adjustable guide vanes and directed onto the vanes of the impeller. The redirection and further acceleration of the water in the impeller generates an impulse which is transmitted to the Francis wheel.
This apparatus is the model of a Francis turbine demonstrating the function of a reaction turbine. The apparatus consists of the Francis wheel, the control device with adjustable guide vanes, a band brake for loading the turbine and housing with a transparent front panel. The transparent cover enables you to observe the water flow, the wheel and the guide vanes during operation. The angle of incidence and thus the speed of the impeller are modified by adjusting the guide vanes.
The turbine torque is measured by means of a band brake and is read on spring balances. For measuring the rotational speed, a non-contact speed sensor is used. A manometer shows the water pressure at the turbine inlet. The flow is detected by means of laboratory beakers and a stopwatch or by a volumetric measurement in the Hydraulic Bench. The measured data make it possible to use the speed in order to determine the characteristic curves as power output, torque and efficiency. The experimental unit is positioned on the working surface of the Hydraulic Bench in a simple and safe manner.
The water supply also is provided via Hydraulic Bench, alternatively, the experimental unit can be operated by the laboratory supply. The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Pipe Friction Apparatus

This Pipe Friction Apparatus has been designed for students to measure pipe friction losses for laminar and turbulent flows. For laminar flow study, an elevated head tank is used for water supply, whilst for turbulent flow, the supply is from the Hydraulics Bench using hoses with rapid action hose coupling. Students may control the flow rate of water by adjusting the flow regulator valve.
The test section is connected to manometers via pressure tappings.


Cavitations Apparatus

Cavitation refers to the formation of vapour bubbles in flowing fluids due to strong low pressure. The unit mounted on the hydraulic bench is used to demonstrate the process of cavitation. It consists of a venturi tube made from clear acrylic to allow an easy visualization inside the section. When water flow rate increases, pressure at the throat is reduced complying with the Bernoulli equation until the vapour pressure of the liquid is reached and small bubbles of vapour form and then they collapse violently as the pressure rises again downstream; this phenomenon is called cavitation. Bourdon gauges indicate the pressure upstream of the contraction, inside the throat and downstream of the contraction. Flow control valves before and after the test section enable to adjust flow and pressure so that the phenomenon of cavitation can be demonstrated. The apparatus consists of a circular/rectangular Venturi-shaped test section manufactured from clear acrylic/precision machined aluminum covered with clear Acrylic to allow full visualisation of flow conditions inside the section. Water enters the test section at relatively low velocity.
As the area of the test section contracts towards the throat the velocity of the water increases and the static pressure falls in accordance with the Bernoulli equation. If the flow of water is increased the sub-atmospheric pressure at the throat causes free and dissolved gasses to be released as bubbles in the liquid. As the flow is increased further the pressure continues to fall at the throat until a limit is reached corresponding to the Vapour Pressure of the liquid (the actual pressure depending on the temperature of the liquid). At this condition small bubbles of vapour are formed in the liquid. These bubbles collapse violently as the pressure rises again in the downstream expansion of the test section. This process is called Cavitation and can be regarded as one of the most destructive forces created in a liquid system - the large amounts of energy released resulting in erosion of even the hardest metal surfaces in real applications such as valve seats, propeller blade s etc. Any further increase in the flow of liquid causes an increase in the Cavitation (the pressure cannot reduce any further than the Vapour Pressure of the liquid). The test section incorporates tappings that allow the static pressure upstream of the contraction, inside the throat and downstream of the expansion to be measured. Each tapping is connected to a Bourdon gauge of appropriate range.
A flow control valve upstream of the test section allows the flow through the test section to be regulated without raising the static pressure in the test section, allowing Cavitation to be clearly demonstrated. Conversely a flow control valve downstream of the test section allows the static pressure in the test section to be elevated - a technique used to prevent cavitation from occurring. The closure of the downstream valve is restricted to prevent damage to the instrumentation. The test section and Bourdon gauges are mounted on a plate with feet that locates on top of the Hydraulics bench. The accessory includes the necessary flexible tubes and a connector to suit the water outlet of hydraulic Bench.


Centrifugal Pump

The centrifugal pump demonstration unit is designed for instructional and experiment of Centrifugal Pump. The unit is set up on a stable base plate and includes a pump, tank, all required fittings and devices for flow rate, temperature, pump speed, intake and discharge pressure. The apparatus has the capability to perform the centrifugal pump characteristics based upon variable speed and variable head of the pump.


Series and Parallel Pump Apparatus

Pumps are used in almost all aspects of industry and engineering from feeds to reactors and distillation columns in chemical engineering to pumping storm water in civil and environmental. They are an integral part of engineering and an understanding of how they work is important. Centrifugal pump is one of the most widely used pumps for transferring liquids. This is for a number of reasons. Centrifugal pumps are very quiet in comparison to other pumps. They have a relatively low operating and maintenance costs. Centrifugal pumps take up little floor space and create an uniform and non-pulsating flow. The Serial & Parallel Pump apparatus is specially designed to demonstrate to students the operating characteristics of centrifugal pump in series, parallel or single pump operation. This training unit operates in close loop. This equipment will explore the relationship between pressure head and flow rate of a single pump and of two identical pumps that are run in series or in parallel. When identical pumps are run in series, the pressure head is doubled but the flow rate remains the same. When pumps are run in parallel the flow is increased but the pressure head produced is approximately the same as a single pump. This equipment also allows the study of efficiency of a pump.
The energy in this experiment is put through two transformations. First, the electrical energy, which is the energy put into the system, is transferred to mechanical energy, which is the energy required to move the shaft and impeller. Second, the mechanical energy is transferred into energy of the fluid. This is accomplished through the pump rotation, which transfers the velocity energy of the water to pressure energy. The overall efficiency is the product of the mechanical (shaft) efficiency and the thermodynamics efficiency.


Fluid Friction Apparatus

This apparatus is designed to allow the detailed study of the fluid friction head losses which occur when an incompressible fluid flows through pipes, bends, valves and pipe flow metering devices.
Friction head losses in straight pipes of different sizes can be investigated over a range of Reynolds' numbers from 103 to nearly 105, thereby covering the laminar, transitional and turbulent flow regimes in smooth pipes. In addition, an artificially roughened pipe is supplied which, at the higher Reynolds'
numbers, shows a clear departure from the typical smooth bore pipe characteristics. Pipe friction is one of the classic laboratory experiments and has always found a place in the practical teaching of fluid mechanics. The results and underlying principles are of the greatest importance to engineers in the aeronautical, civil, mechanical, marine, agricultural and hydraulic fields.
Osborne Reynolds distinguished between laminar and turbulent flow in pipes in his publication in 1883. Ludwig Prandtl, Thomas Stanton and Paul Blasius later analysed pipe flow data in the early part of this century and produced the plot known as the Stanton diagram. John Nikuradse extended the work to cover the case of rough pipes and one such pipe supplied with this equipment has been roughened for flow comparison purposes.
In addition to the equipment for the study of losses in straight pipes, a wide range of accessories is available including pipe fittings and control valves, a Venturi tube and an orifice plate assembly.


Fluid Properties & Hydrostatics Bench

This unit demonstrates the properties of the fluids and their behavior under hydrostatic conditions and provides numerous experiments an hydrostatic of liquid. It also provide know ledge about the fundamental principles.
With this well equipped hydrostatics bench, numerous experiments on the topic of the hydrostatics of liquids and gases can be carried out. A pipe section and various pressure measuring devices are fitted to a laboratory trolley with a demonstration panel, working area and cabinet. Various measuring containers are integrated into the pipe section.
The sealed water circuit and pump with supply tank permit experiments to be performed independent of a mains water connection. This feature makes the bench particularly suitable for use in seminars rooms and lecture theatres. Further experimental apparatus are included in the cabinet, e.g. a device for determining the centre of pressure of a column of water. This enables the pressure on a weir to be determined, amongst other aspects.


Multi-purpose Teaching Flume

Hydraulic engineering is concerned with artificial waterways, the regulation of rivers and with barrages, amongst other things. By using experimental flumes in the laboratory, it is possible to teach the necessary basic principles. The experimental flume OF.FMH/33 has a closed water circuit. The cross-section of the experimental section is 309x450mm. The length of the experimental section is 5m. The side walls of the experimental section are made of tempered glass, which allows excellent observation of the experiments. All components that come into contact with water are made of corrosion-resistant materials (stainless steel, glass reinforced plastic). The inlet element is designed so that the flow enters the experimental section with very little turbulence. The inclination of the experimental flume can be finely adjusted to allow simulation of slope and to create a uniform flow at a constant discharge depth. A wide selection of models, such as weirs, piers, flow-measuring flumes or a wave generator are available as accessories and ensure a comprehensive programme of experiments. Most models are quickly and safely bolted to the bottom of the experimental section.


Rotating Tank Vortex, Rotating Tank

The Vortex Apparatus enables students to produce both free and forced vortices, and measure the vortex water surface profile. The equipment consists of a transparent vessel on a support frame, which mounts on a hydraulic bench. It may also work with another suitable clean water supply and drain. A low-voltage, variable-speed motor rotates the vessel about its vertical axis. A speed-control unit (included), sited away from the main apparatus, controls the speed of rotation. To produce a forced vortex, students add water to the rotating vessel until it is about half full. A forced vortex forms. After a few minutes the vortex becomes constant, and students can measure the surface profile using the traverse probe. The traverse probe can move both horizontally and vertically, and both axes have linear scales. Students can also measure distribution of total head by replacing the traverse probe with a Pitot tube. To produce a free vortex, students place a smaller, perforated transparent cylinder inside the main vessel. This forms an annulus into which a continuous water supply is directed.When the vessel rotates, water passes through the perforations and spirals slowly inwards to a small hole in the centre of the base of the vessel. The surface falls rapidly towards the centre and produces an air core. Studentsmeasure the surface profile using the traverse probe.


Reciprocating Pump Demonstration Unit

The Reciprocating Pump demonstration unit enables the pump curve of a reciprocating pump to be measured. The system consists of the pump with an electrical drive motor, the pipe system with supply tank and a container for volumetric flow measurement. Gauges provide the delivery pressure and the pressure in the cylinder. The pressure level in the system is maintained constant using a pressure retention valve. The pulsating pressure characteristic of the pump can be damped with an air vessel.


Multi-Purpose Teaching Tilting Flume

The OF.FMH/43 is a small open channel flume, with clear acrylic sides to the working section for total visibility of the flow. The channel is fitted with a PVC inlet tank, and is designed for free discharge into the Hydraulics Bench. The flume is mounted on a rigid framework, and can be tilted by use of a calibrated screw jack, which allows accurate slope adjustment of the channel. The inlet tank incorporates a stilling arrangement to diffuse the water flow prior to entry into the channel, ensuring smooth uniform flow. The level in the working section of the flume is controlled using an overshot weir at the discharge end. Bed pressure tappings and fixing points for models are provided. A longitudinal scale positioned at the top of the channel allows depth gauges and Pitot-static tubes to be accurately positioned along the channel length. The flume is designed for use with a standard Hydraulics Bench, which provides the pumped water flow, the flow control valve and a volumetric tank for flow measurement. Also available is an optional flow meter which can be fitted to the allow direct flow measurements to be taken.


Basic Hydrology Apparatus

In civil engineering, studies in hydrology are conducted in connection with the design, construction and operation of hydraulic engineering systems and water management functions. These studies focus on topics such as seepage and flow of water in the soil and the use of groundwater resources. OF.FMH/45 can be used to study seepage and groundwater flows after precipitation. Variable precipitation density and areas and different groundwater supply and drain possibilities allow a wide variety of experiments. OF.FMH/45 contains a closed water circuit with storage tank and pump. The core element is a sand-filled, stainless steel experiment tank with inclination adjustment. To study precipitation, a precipitation device is available. The precipitation device consists of two groups of four nozzles. Water can flow in (groundwater) or out (drainage) via two chambers on the side. The experiment tank is separated from the chambers by fine mesh screens. To study the lowering of groundwater, two wells with open seam tubes are available. Water supply and water drain can be opened and closed, thus allowing a wide variety of experimental conditions. At the bottom of the experiment tank there are measuring connections to detect groundwater levels, which are displayed on 19 tube manometers. The water supply is controlled by a valve and read on a flow meter. The water drain is determined by a measuring weir.


Visualisation of Seepage Flows

A descriptive method in the study of seepage and groundwater flow is the visualisation of the streamlines and their graphical representation as a flow net. The flow net provides information about the seepage of water in dams and sheet piles. OF.FMH/49 can be used to visualise streamlines in seepage and groundwater flow on different models using a contrast medium.
Furthermore, the effects of water pressure on different structures are displayed as pressure curves. The trainer consists of a transparent tank with a sand filling. Various models can be placed in the sand bed to demonstrate typical structures. The experimental section is separated from the feed and discharge chambers by fine mesh screens. A valve is used to adjust the water supply. Using a contrast medium it is possible to make streamlines visible, as they occur in seepage and groundwater flow. A tempered glass viewing window allows for optimal observation of the experiments. Various models allow an extensive range of experiments, such as pressure distribution on retaining walls or seepage and groundwater flow under sheet piles. OF.FMH/49 contains a closed water circuit with storage tank and pump. The well-structured instructional material sets out the fundamentals and provides a steps-by-steps guide through the experiments.