JEMS INDUSTRIES

Chinchwad, Pune, Maharashtra

A domestic refrigerator is one of the simplest of refrigeration devices widely used all over the world. It uses a fractional HP hermetically sealed compressor, a natural convection condenser, a capillary tube as an expansion device, and direct expansion type roll-bond evaporator. As far as the controls are concerned, an ON-OFF type thermostat controls the average temperature of the refrigerator. The inside heat transfer takes place by natural convection and convective currents set due to density difference of cold and warm air.

List Of Experiments:

1. To study construction and working of a domestic refrigerator.
2. To plot the cycle on P-H Chart.

Rating conditions * : Ambient temperature= 35^o C, atmospheric pressure = 1.01 bar, suction pressure=35 psig, discharge pressure= 180 psig, evaporation temperature=7.7^o C, discharge temperature=55^o C

The apparatus consists of a small test sphere. This sphere is heated by a hot bath, till the steady state is reached and then it is coolled in air or water / oil. During both, heating and cooling of sphere, temperature of sphere is a function of time and hence, it is a unsteady state of heat transfer process. The temperature of sphere is measured by thermocouple. The hot bath is provided to heat sphere with temperature controller to facilitate to conduct experiment at different temperatures.

Specifications:

• Test piece with thermocouples - 2 No.s of different materials.
• Hot bath with heater and controller.
• Cold bath.
• Digital Temperature Indicator.
• 15 Amp., 230 V.A.C. power supply.

Now a days gyroscope is a very important tool used for various controls in high technology vehicles. For minimising rolling, yawing and pitching of ship or air craft Gyroscope is used. Balloons use Gyroscope for controlling direction. Gyroscope has applications in space craft, space platforms. Thus study of Gyroscope is of high importance for any Engineering student.

Description

The Motorised Gyroscope consists of a disc rotor mounted on a horizontal shaft rotating in the ball bearings of one frame. The rotor shaft is coupled to a motor mounted on a trunion frame having bearings in a yoke frame which is free to rotate vertical axis. Thus the disc can be rotated about three perpendicular axis. Angular scale and pointer fitted to frame helps to measure precession rate.

Features

• Demonstration of relationship between applied torque and precession rate alongwith direction of rotation.
• Gyroscopeic couple easily varied by weights.
• Precisely balanced rotor.
• Useful to verify the relationship- T=lw.wp

Specifications

• Disc Rotor- 30 Cm. dla., 10mm thick approx.
• Drive - FHP, AC/DC Single Phase Motor.
• Dimmerstat to vary speed of motor.
• Weight Set.

Range of Experiment

• Observation of Gyroscopic behavior( Two Laws of Stability )
• Experimental justification of the equationT=lw.wpFor calculating the Gyroscopic couple by observation and measurement of results for independent variations in applied couple T and precession wp.

Service Required

• 230Volts, A.C.stabilised supply.
• Tachometer.
• 1m X 1m space at working height.

It is motorised unit consisting of SUN gear mounted on input shaft, two plane gears meshes with the annular gear. These planet gears are mounted on a common arm to which output shaft is fitted. Loading arrangement is provided for loading the system and to measure Holding Torque.

Specifications:

• A compact Epicyclic Gear Train coupled with D.C. Motor.
• Rope brake arrangement to measure Output torque and Holding torque.
• Control Panel comprising of - Digital Ammeter and Voltmeter. RPM Indicator. Speed Controller

Experiment :

1. To measure epicyclic gear ratio between input shaft & output shaft.
2. To measure epicyclic gear ratio between input shaft and holding drum.
3. To measure Input torque, Holding torque and Output torque.

Service Required :

• 230 V.A.C. stabilised power supply.

By photoelasticity principles, a diffused light or lens type polariscope, generates the data of principle stress difference at various points on the model. But when these values of shear stress are not sufficient for our purpose and when we desire to have separate values of principle stresses at a point, we adopt some more means of separating these stresses.Shear difference method, oblique incidence method, electric analogy method are various methods used for this purpose

Shear difference method is a theoretical mathematical method of separating the stresses. But this method is very tedious and time consuming and often needs a computer for analysis of complete model. Electric analogy method, which works on laplace equation, needs very costly equipment. Oblique Incidence method is a method of separating the principle stresses in which one more relation between two principle stresses is obtained by directing the light incident on model on oblique angle.

An Equipment
This is a simple device to be used as on accessory along with a polariscope. It consists of a pair of prisms fitted in two separately rotable prism holders. These prisms change the direction of light incident on it. A prism on light box side deflects the light in 450 A second prism makes this oblique ray of light, parallel to original ray of light. So the model kept between two prisms, receives a light ray at an angle, which is 450 in this case. A scale reads the angular position of these prisms. A linkage fabricated from square bars is provided to adjust the X , Y and Z co-ordinates of prism so as to reach at the point of interest.

The display board consist nearly all the components used in refrigeration system. The arrangement of parts such that, all the parts are visible and the construction can be easily understood. The components are mounted rigidly on the wooden / powder coated steel frame. Nomenclature helps to identify each component.

The test rig consists of suitable equipment for performing experiments to measure the steam turbine efficiency, steam quality, and flow rate and condenser effectiveness. The turbine is suited for operation with a 300kg/hour, 10bar saturated steam supply.

1. Steam turbine: The turbine is a single stage impulse turbine with two stainless steel nozzles. The blades are also made of stainless steel to ensure high reliability. The turbine is of vertical split case design to provide easy serviceability.
2. Separating and throttling calorimeter: Consists of well insulated separating and throttling chambers made of MS pipes with suitable piping, valves, thermometer and pressure gauges. A condenser is included to condense the sampled steam and measure its actual mass.
3. Condenser assembly: Consists of a shell and tube type condenser and a 3.0HP monoblock pump set (440Volts, 3 phase, 50Hz) to circulate the cooling water. An orificemeter with pressure gauges and thermometers are fixed in the cooling water pipeline to measure the flow rate and temperature rise. Suitable piping and valves are provided to connect the turbine exhaust to the condenser and atmosphere. The steam flow rate is determined by measuring the condensate.
4. Other accessories: Suitable 25mm piping (not exceeding 3.0m) and control valve to connect the turbine with the calorimeter and to the boiler. Necessary pressure gauge is provided to measure turbine steam inlet conditions. A digital tachometer is provided to monitor the turbine speed.
5. Loading Device: The steam turbine is coupled to a 3000 rpm, 1KW, 220 Volts, generator on a strong base plate. A panel board consisting of ammeter, voltmeter and a row of bulbs is provided.

With a steam flow rate of 300 kg/hour 10 kg/sq.cm saturated conditions, the turbine will produce Boiler Details:Steam Boiler of capacity 300 kg/hr., (made by Elite Boilers, Pune or equivalent) with working pressure of 15 kg/cm2 model STEAMPACK- 300 (f & a 30 C) LDO/HSD fired. As per ERECTION OF 300Kg/hour Boiler and Supply of accessories.

1. Suitable Water Tank (sintex tank)1000 ltrs
2. Suitable Fuel Tank (MS tank) - 100 ltrs
3. Suitable Chimney 1 No (4 Meters Long)
4. Suitable Water Softener 1 No.
5. Water Line from Softener to Tank, water tank to boiler
6. Fuel Line from Fuel Tank to Burner and back
7. Steam Line to Steam Turbine
8. Condensate Drain Line
9. Softener and water Pump

Other accessories required for the steam turbine test rig:1. A suitable sump tank of capacity at least 10, 000 liters is required for the condenser coolingwater supply. Existing lab sump if it is of sufficient capacity can be used for this purpose.Necessary GI piping to connect the condenser pump to the sump and the condenser and returntrenches are to be provided by the college.2. Necessary foundation for the turbine, condenser, and boiler.Optional: Cost of cooling tower (instead of the sump tank) Rs.55, 000(Rs. fifty five thousand only)

Feed Pump Motor, Blower Motor and oil Pump2) STEAM BOILER CONSTRUCTIONIt is designed on forced circulation Heat Exchange principle fabricated out of hightemperature resistant seamless tubes, once through spiral coil nest is arranged to give 3 clearpasses of flue gases forms combustion zone. It ensures for optimum rate of heat release andmaximum heat transfer and low stack temperature. It is ultimately placed in double shell onstudy steel frame for quick and easy installation.3) SHELL AND COIL ASSEMBLYInner & Outer shell, Aluminium foil in between two shells to act as heat retarder, Nestof once through spiral coil to give 3 clear pass and Top & Bottom refractory block.4) BURNER, BLOWER & OIL PUMP ASSEMBLYCentrifugal Blower coupled with motor, vertically downward position placed burnercomplete with nozzle, nozzle holder, diffuser plate, ignition electrodes, photocell, sight glass& solenoid valve. Gear oil pump coupled with motor, Oil filter and Pressure gauge.5) FEED WATER ASSEMBLYPositive displacement type piston pump coupled with motor, pulley, V-Belt, Pumpsafety valve & Non-return Valve.6) MOUNTINGS, FITTINGS & INSTRUMENTATIONMain steam stop valveSteam Auxiliary valveSafety ValveBlow down valveSteam trapNon return valveStrainerOil, water & steam pressure gauge with isolating valvesTemperature Indicator cum controllerFlue gas controllerSteam pressure switchAudio AlarmOil filerIgnition Transformer7) ELECTRICAL PANELIt is mounted on the front side of the boiler at a convenient height, is prewired andcomplete with starters, push buttons indicating lamps all duly labeled, fuses, O/L relays, contactors and sequence controller.8) ACCESSORIES

• Air blower
• Water pump (Feed Water)
• Fuel pump
• Pressure control : Through HP/LP cutout, Solenoids, pressure switches

9) INSULATONThe steam line connecting the Turbine will be well insulated.10) FINISHRed oxide primer and one coat of enamel paint11) BASEStrong Channel Base, Houses all parts of boiler12) SOFTENERWater softener suitable for softening raw water up to 200 PPM of CaCO3 complete withinter connection piping, valves, Filter, Resin, Pressure Gauge, Ejector & brine tank13) Fuel Tank: 100 liter capacity MS fuel tank14) Feed water tank: 1000 liter capacity sintex tank15) Piping: Water line, fuel line, steam line (blow down line and line to connect boiler withturbine, etc)16) Thermal lagging for steam pipes17) Flue gas arrangement - Chimney 4 m height chimney

In the field of present engineering development, stress strain analysis by photoelastic methods plays an important role. This method provides a means for visualisation of stress patterns spread across the cross section of loaded specimen and determination of principle stress difference in the whole field. The magnitude of stress at every point can be determined in the simple way by using usual Principle Stress Separation Technique. TechnoLab PHOTOELASTIC POLARISCOPE is designed for plane as well as circular polariscope arrangements and can be used with a wide range of complicated shaped models under various loading arrangements.

Specifications:This is the transmission type polariscope highly useful for two dimentional stress analysis. Major components of polariscope are-

Optical Elements-

1. Polariser
2. Quarter wave plate No.1
3. Quarter wave plate No.2
4. Analyser

Each optical element is snadwitched between two strain free acrylic sheets and mounted in metalic ring. These metalic rings are mounted in two separate housings. The quarter wave plates can be rotated to insert or remove optically to make plane or circular polariscope. Scale is fitted on analyser to read the angles and fractional fringe orders in tardy's method of compesation. Diameter of all optical elements is 300 mm approx.

LightBox-
Wel ventilated light box contains white light source and monochromatic light source with diffusing glass. White light is obtained from fluroscent tubes and sodium light is used to obtain monochromatic light. Small fan is provided for cooling. Light box also houses Digital Load Indicator for Load Cell.

Universal Loading Frame-
An universal Loading frame is provided along with polariscope so as model under observation can be loaded under tension, compression or bending load one at a time. Arrangement is provided for both transverse and vertical movements of frame so as to keep point of interest at the center of field. A universal load cell is provided to measure load on model. Necessary pins, links and shekels are provided along with unit. Capacity of loading frame is 200 Kg.All above components are mounted on sturdy table. Photoelastic models of Ring, Disc & Beam will be supplied along with unit-

Service Required :

• 230 Volts, 50Hz stabilised power supply.
• Plate type camera for photography.

The apparatus consists of a nichrome wire immersed in water. The Nichrome wire is heated by passing current through it. Input to the nichrome wire is controlled by dimmer stat. As one goes on increasing wire input current, at critical heat flux, the wire brakes which is measured on meter. We can visulise natural convection and pool boiling. A separate bulk heater is provided to conduct experiment at various temperatures.

Specifications:

• Glass trough placed on a tripod housing water, test & bulk heater.
• Thermometer to measure water temperature.

Instrumentation & Controls :

• Digital Voltmeter - 0 - 199.9 Volts.
• Digital Ammeter - 0 - 19.9 Amp.
• Heater Control .
• Necessary switches and Fuses.

Service Required :

• 230 V.A.C. stabilized supply with earthing.
• Floor space - 1.5m X 1.5 m approx.

Heat Exchangers are devices in which heat is transferred from one fluid to another. This apparatus is a tube in tube type concentric tube heat exchanger. Hot fluid flows through inner tube and clod fluid flows through outer tube. The direction of clod fluid flow can be changed from parallel flow to counter flow with the help of valves. Thermometer pockets with thermometers are provided to measure temperatures of incoming and outgoing cold and hot fluid.An electrical geyser of sufficient capacity is provided to obtain hot water. Flow rates of cold and hot water can be controlled by means of valves and measured by measuring flask. Main test section is insulated to minimise heat losses.

Specifications:

• Length of heat exchanger - 1.5 m.
• Outer Tube- G.I. O.D. 38 mm I.D. 27.5 mm.
• Inner Tube - Copper, O.D. 12.5 mm.
• Thermometers -0 to 50 ⁰C - 2 No.0 to 100 ⁰C- 2 No.

• Measuring Flask & Stop Clock.

Experimentation :

1. Determination of overall heat transfer co-efficient for a tube in tube type heat exchanger.
2. To calculate -
   1. Rate of heat transfer.
   2. L.M.D.T.
   3. Theoretical overall heat transfer co-efficient.

Service Required :

• 230 V.A.C. stabilized supply with earthing.
• Water supply about 10-15 l.p.m. at constant head.
• Adequate drainage system.

This is an open circuit Wind Tunnel which provides a region of controlled airflow into which models can be inserted. The propulsion is provided by a fan at downstream of working section.The tunnel consists of bell mouth shaped entry to guide the air smoothly into settling chamber consisting of honeycomb and nylon mesh screens which filters and stabilizes the air flow. This follows working section or test section where various models can be tested. Two windows with acrylic sheet one each on either side will be provided for visual observation. Working section is followed by diffuser section, which reduces the dynamic pressure at the exit.A three -blade fan coupled with D.C variable speed motor is used to produce desired wind velocity. A thyristorised motor control is used for smooth variation of air velocity.

SPECIFICATIONS :

1. Type : Open type Wind Tunnel.
2. Test Section : 300mm x 300mm x 1000 mm. long with two Perspex windows.
3. Blower Fan : 3 /10 blades M.S. /nylon fan.
4. Motor : 7.5 HP D.C shunt motor, 1500rpm.
5. Speed Controller : 3 phase, thyristor controller to give smooth Speed control.
6. Air Velocity : In test section - 1 to 30 m/sec.
7. Duct : Manufactured out of ms sheet.
8. Length of Tunnel : 4/5 meter.

INSTRUMENTATION:

1. LIFT & DRAG INDICATOR -
   1. Lift - Display: - 3 digit, Least count: - 0.1 kgRange : - 20 kg
   2. Drag - Display: - 3 digit, Least count: - 0.1 kgRange : - 20 kg
2. MANOMETERS: -
   1. Multitube Manometer : 500mm. Height, 500mm, width, 15 pvc tubes, 6mm, dia,
   2. Pitot tube : 100cm. Long chrome plated pipe tube, 3/8 dia.
3. WOODEN MODELS :-
   1. Aerofoil:
      1. Symmetrical
      2. Unsymmetrical. 150mm, width and 150mm.long with 15 piezometric tapping with 0-360 degree protractor.
   2. Cylindrical Model: 75mm, dia., 150mm long with piezometric tapping and 0-360 degree protractor.
   3. Spherical Model: - 65mm, dia.

   EXPERIMENTATION :-

   1. To study pressure distribution around a) Aerofoil b) Cylinder.
   2. To measure lift & drag on airfoil model, cylinder model & sphere model.

Description:A cascade system is a multistage application in which two separate refrigerant systems are interconnected in such a manner that one provides the means of heat rejection (condenser) for the other.The lower system may, therefore may operate at a much lower temperature. Cascade system has the additional feature, over compound systems of permitting the use of different refrigerants in each cycle of the cascade.

ADVANTAGES:

1. The principal advantage of the cascade system is that, it permits the use of two or more different refrigerant, thus each refrigerant circuit is comparatively simple.
2. Each refrigerant can be chosen that operates best within the required comparatively narrow temperature and pressure range. For example, a refrigerant, which does require a vacuum in the evaporator to produce a low suction temperature, is selected for the low stage system. Another refrigerant such as R-404 A, which does not require an excessive pressure in the condenser, is selected for use in the high stage system.
3. As each cycle is operating separately, there is no difficulty of lubrication.
4. The refrigerants used in the system will have successively low freezing temperatures, so that refrigerants having low freezing point can be used in high temperature circuit and refrigerant having high freezing point can be used in the low temperature circuit.
5. Inclusion of inter-cooling with liquid refrigerants in the cascade system improves the performance of the system.

Cascade system is just similar to the binary vapour cycle used for the power plants. In the Binary vapour cycle a condenser for mercury works as a boiler for water.Similarly, in the cascade system the condenser for low temperature cycle works as an evaporator for the high temperature cycle.In a cascade system, a series of refrigerants with progressively lower freezing points is used in the series of single stage unit.

All the components of cascade system are mounted on the powder coated fabricated stand. The cascade system is divided in the three parts. These are as follows: High side , Intermediate stage and Low side.The cascade system consist of hermetically sealed compressors, shell and coil type condenser, desuper-heater, water flow cut-out, expansion device, expansion chamber, cascade condenser, oil-Seperator, and low-side evaporator. The refrigerant used on the high side is R -404a, and the refrigerant used on the low side is SUVA-95.On the high side a hermetically sealed compressor, shell and coil type condenser, drier/filter, flow meter, expansion device, and cascade condenser are connected to each other.On the low side a hermetically sealed compressor, oil Separator, De-super heater, cascade condenser, drier/filter, expansion device, low side evaporator, expansion chamber, cooling fan are connected with each other.Separate pressure gauges are provided to measure the pressure at the compressor inlet and compressor outlets. HP/LP cutout is used as a safety device.Cooling thermostats are provided in the cascade condenser and in the low side evaporator. Separate energy-meters are provided to measure the energy consumed by the compressor and the heater. A dimmer is also provided to control the input of the heater. Flow meter in the liquid line is incorporated to measure the refrigerant flow. Digital temperature indicator displays temperatures at various locations as per the selection viz. temperature before and after compressor and before and after expansion.

List Of Experiments:

1. To evaluate the cooling capacity of cascade system.
2. To evaluate actual and theoretical C.O.P. of Cascade Refrigeration system.
3. To plot the actual Refrigeration Cycle on P-H and T-S charts.
4. To study various components and controls used in Cascade Refrigeration system.

Rating conditions * : Ambient temperature= 35^o C, atmospheric pressure = 1.01 bar,

CUSTOMER SCOPE:

1. A CONTINUOUS WATER SUPPLY OF 50 LPM@2.5 BAR AT AMBIENT TEMPERATURE OR A COLING TOWER OF 5 TR CAPACITY.
2. ELECTRICAL POWER POINT 415 VOLTS, 50 HZ, 3 PH, WITH 32 AMPS MCB.
3. CLEAR SPACE OF 3MTR X 2 MTR.

Vapour Absorption Refrigerator earlier known as Electrolux refrigerator is an self contained refrigerator working on absorption technology.In the absence of a compressor or pump, the circulation takes place by density difference. The system is pre-charged with three fluids namely water, ammonia and hydrogen. Hydrogen is used as an inert gas and does not undergo any phase change and heat transfer processes. Its purpose is to keep the pressure of the system constant. It uses an electrically operated generator, where, the ammonia vapours dissolved in water are separated and pure ammonia vapours enter the condenser. In the condenser, the high pressure vapours reject its latent heat to the surroundings and get liquefied. The liquid ammonia expands through expansion device where its pressure and temperature is reduced and cold low pressure vapour enters the evaporator where it absorbs heat from the space to be cooled and then vaporized ammonia absorbs in water. This strong solution then enters the generator and the cycle repeats. PRINCIPLE OF OPERATION:Electrolux principle works on 3-fluid system. There is solution circulation pump. Total pressure is the same throughout the system. The third fluid remains mainly in the evaporator thus reducing partial pressure of refrigerant to enable it to evaporate at low pressure and hence low temperature.The schematic diagram of the Electrolux refrigerator working on NH3-H2O system with H2 as the third fluid is shown in figure. Liquid NH3 evaporates in the evaporator in the pressure of H2.Hydrogen is chosen as it is non corrosive and insoluble in water.A thermosyphon bubble pump is used to lift the weak aqua from the generator to the separator. The discharge tube from the evaporator the generator is extended down below the liquid level in the generator. The bubbles rise and carry slugs of weak NH3-H2O solution into the separator.Two U-bends are provided as vapour- locks to prevent H2 from getting into the high side or solution circuit.Partial pressure of H2 provides the pressure difference of NH3 between the condenser and evaporator. Accordingly, we have:In condenser pure NH3 vapour pressure = Total pressure In evaporator NH3 vapour pressure = Total pressure - partial pressure H2For example, consider the condenser temperature at 50 C , and evaporator temperature as -15 C. The corresponding vapour pressures of NH3 are:Condenser, Pk = 20.33barEvaporator outlet, Po2 = 2.6barThe approximate pressures in various parts of the system, then will be as given in the table.

It has been assumed that vapours leaving generator top are in equilibrium with entering rich solution at 40 C, at which temperature saturation pressure of NH3is 15.45bar. It has also been assumed that the temperature at evaporator inlet is -25 C at which temperature saturation pressure of NH3 is 1.516bar.

Specifications subject to change without any notification.

LIST OF EXPERIMENTS:

1. To study construction and working of a vapour absorption refrigerator
2. To evaluate performance of the refrigerator by calculating the C.O.P of the system.