Unicon Instruments

Forced Convection Apparatus:

The unit consists of a circular pipe; loosing heat by forced convection
to air, being forced through it. Constant heat flux is added to pipe by an electrical heater, provided with input control. The pipe surface temperature is measured at various points along length of pipe. Temperature of air at inlet and outlet of test section are measured. Thus the students can calculate local and overall heat transfer coefficients in forced convection, at various airflow rates and various heat flux values.

SPECIFICATIONS

1. Test pipe - 32mm NB GI pipe, 500 mm. long, heated by band heater, outside.
2. Centrifugal blower to force air through test pipe with How
   control valve.
3. Variac 2A, capacity to force air through test pipe with flow control valve.
4. An orifice meter with differential water manometer.
5. Voltmeter and Ammeter to measure heater input.
6. Multichannel digital temperature indicator to measures various temperatures.

A technical manual accompanies the unit.

SERVICES REQUIRED:

1. Bench area of about 1m. x 0.75 m. at working height.
2. 239v, 15A, AC, supply with earthing connection.

Emissivity Measurement Apparatus:

The apparatus consists of a test plate and a comparator. A black plate
is used as a comparator for test plate. When all the physical, dimensions and the temperatures are equal, heat losses from both plates will also be the same, except radiation losses. Hence the input difference will be due to difference in emissive. Both the plates are kept in a panel enclose with perplex front and are given inputs through separate dimmerstats so that temperatures of both can be kept equal. Thus emissivity can determine over a wide range of temperatures.

SPECIFICATIONS

1. Test plate and Black plates — 160mm. Dia. Aluminum plates, mounted in Panel with mica heater inside.

1. Instrumental panel consisting of-

Voltmeter and ammeter for input measurement to both heaters through a selector switch.

Separate dimmers for both the plates.

Multichannel digital temperature indicator.

A technical manual accompanies the unit.

SERVICES REQUIRED:

1. Space area of 1.5m x 1 m. at working height.
2. 230v, 15A, AC supply with earthing connection

Stefan Boltzmans Apparatus:

The Stefan Boltzmann constant is an important constant in heat transfer. The apparatus determines Stefan Boltzmann constant. The apparatus consists of a hemisphere surrounded by hot water. Hot water is obtained from a water-heating tank. When the blackened disc is inserted at the center of hemisphere, heat is transferred into the disc from hemisphere by radiation and its temperature begins to rise, and from temperature raise rate. (It is measured at the intervals of 5 sec.) Stefan Boltzmann constant is
determined.

SPECIFICATIONS:

1. Water heating tank provided with electric immersion heater.
2. Hemisphere made of copper sheet, 200mm. dia. Surrounded water jacket of 250mm. Dia.
3. Test disc made of copper 20mm. dia. provided with thermocouple at the center.
4. Multichannel digital temperature indicator 0-200 C with 0.1C least counts to measure the temperature of hemisphere and disc.
5. Audible buzzer with timer to ring at every 5 seconds.

A technical manual accompanies the unit.

SERVICES REQUIRED:

1. Bench area of about 1m. x 05m. at working height.
2. 230v, 15A, AC, electric supply with earthing connection

Concentric Tube Heat Exchanger: 

(A)Plain Tube ( Water To Water ):

The apparatus consists of two concentric tubes. Inner tube consists of copper tube through which hot water flows. While the outer tube consists of GI pipe through which cold water flows. The arrangement enables the parallel and counter flow of the cold water. The inlet and outlet temperatures and the flow measurement enable to find out the heat exchanged LMTD, and effectiveness of the equipment.

Specifications:

1. Inner copper tube I.D, 12.7mm. and outer G. I. Pipe I. D. 15mm. approx. and 1.5m. length.
2. Thermometers - 4 nos.
3. Measuring flask - 1 Lit. capacity.
4. Geyser-3 kW. Single phase.

Services required-

1. 220v, 15A, stabilized single-phase AC supply.
2. Floor area - 3m x I m x 1 m height.

(B) Finned Tube ( Water To Air ):

The apparatus consists of two concentric tubes. Inner tube consists of copper tube through which hot water flows. It is finned at its outer diameter to increase the heat transfer surface.   While the outer tube consists of GI pipe through which cold air flows. The arrangement enables the parallel and counter flow of the air. The inlet and outlet temperatures and the flow measurement enable to find out the heat exchanged LMTD, and effectiveness of the equipment.

Specifications:

1. Inner copper tube I.D. 12.7mm. and outer G. I. Pipe I. D. 25mm. approx. and 1m. length.
2. Thermometers - 4 nos.
3. Orifice meter along with manometer.
4. Measuring flask - 1 Lit. Capacity.
5. Geyser-3 kW. Single phase.

Services Required

1. 220v, 15A, stabilized single-phase AC supply.
2. Floor area - 3m x 1m x 1m height.

Shell & Tube Heat Exchanger ( Water To Water ):

Heat exchanger is the devices used to transfer the heat from one fluid to other. The shell and tube heat exchanger is two tube single pass heat exchanger. The hot fluid is hot water obtained from water heater. The coil fluid is cold water. The schematic flow arrangement is shown in figure. Hot water enters the lower side of end box, flows through the tubes in lower half of shell and comes to the other end of the shell. It reverses its direction, flows through tubes in upper half of the shell and leaves out. Cold water enters lower part of the shell passes over the tubes between the baffles and leaves out the shell through outlet at upper surface of shell.

SPECIFICATIONS:

1. Shell - 150NB, 750 m.m. long provided with end boxes.

One end box with divider plate.

25% cut baffles - 4 Nos. in the shell.

1. Tubes - 4.5mm I.D., 6.35mm O.D.,250 m.m. length copper tubes with triangular pitch.
2. Instantaneous water heater, 3 Kw capacity, to supply hot water.
3. Thermometer for measuring the water temperature.
4. Valves to control hot and cold water flow.

SERVICES REQUIRED:

1. 3 P H, AC supply
2. Floor space 1.5m. X 1m,
3. 230V, 15A, AC supply with earthing connection.
4. Water supply at the rate of about 10 lit/min at constant heat.

Thermal Conductivity of Metal Rod:

The apparatus consists of a copper bar, which is heated at one end, a heat sink is provided at other end. The test section of bar is properly insulated and thermocouples are attached along the length of bar. Heat conducted through the section of bar is measured by heat collection in water-cooled heat sink. A panel comprising of controls and measurements is provided, which provides easy operation and sturdy mounting of unit.

SPECIFICATIONS

1. Metal Bar - 25mm of adequate length, provided with 8 Thermocouples along the length, Band heater at one end and water-cooled heat sink at other end. Test portion of bar is insulated.
2. Instruments panel comprising of.

Voltmeter ... 1No.

Ammeter ... 1No.

Dimmerstat 0-230v, 2A, capacity.

Multichannel Digital temperature Indicator.

1. Measuring flask and stop clock

SERVICES REQUIRED

1. Bench area of 1.5m. x 1m. at working height.
2. 230 v, AC, electric supply with earthing connection.
3. Water supply at the rate of 2 lit/mm

Lagged Pipe Apparatus:

The apparatus consists of three concentric pipes mounted on suitable stand. The space between innermost and the middle pipe is fifed with a lagging material and the space between the middle and the outer most is filled with and other lagging material. The lagged pipe is heated with a cartridge heater inserted at the axle length of the pipe. Voltmeter and ammeter on the panel can measure the input to the heater. The intermediate temperatures can be measured by the thermocouples attached at the surfaces of the pipe. Thus the resultant conductivity of the materials can be found out.

SPECIFICATIONS:

1. Pipes :

• Gl pipe (innermost) - 6 cm. (Outer Diameter).
• Gl Pipe (Middle) - 8.5 cm. (Mean Diameter)
• G! Pipe (Outermost) - 10.7 cm. (inner Diameter)
• Length of pipes 1 Meter.

1. Heater :

Nichrome wire cartridge heater placed centrally, of suitable capacity.

1. Control Panel :

Single Phase Dimmerstat - 1 No.

Voltmeter (0 - 250V) - 1 No.

Ammeter (0- 2A) - 1 No.

1. Temperature Indicator :

Multichannel Digital Temperature Indicator ranging (0 - 300 C) using Cr/AI Thermocouples

Services Required:

1. A.C. Single Phase 230 V electric supply

2. Floor Area-1.5 Meter X 1 Meter X 0.5 Meter High

Thermocouple Calibration Test Rig:

The Unit helps in calibrating given thermocouple for the range 0°C to 100°C. While calibrating, thermocouple is once dipped in ice for 0Q C and then in boiling water for 100°C. This is done till the thermocouple shows the actual temperature of ice (0° C) and boiling wafer (100°C) and a linear calibration is set. A mV meter is provided to know the corresponding voltage.

SPECIFICATIONS:

1. A digital mV Meter and a digital temperature indicator with 2 different type of thermocouples.
2. A water container with heater of 1 KW. 

A technical manual accompanies the unit.

SERVICES REQUIRED:

1. Table surface area - 2 m X 1 m X 0.5 m height.
2. 220V, 50hz. Stabilize Electric Power Supply.
3. Ice cubes - 0.5Kg. Approx.

The unit consists of a vertical brass pipe heated by a cartridge heater
inside it. The pipe looses heat to atmosphere by natural convection. It is fitted in an enclosure to provide undisturbed natural convection currents. Thermocouples are attached on the pipe to measure local temperatures. Heater input is measured on voltmeter and ammeter. Thus students can determine overall heat transfer coefficient and local transfer coefficients in natural convection at various heat transfer rates.

SPECIFICATIONS

1. Pipe - Brass pipe, 38mm. dia. (OD) 500mm. long, fitted with cartridge heater inside.
2. Thermocouples are fitted along with the length of pipe for Temperature measurement - 7 nos.
3. Enclosure 200mm. x 200mm. x 800mm. size, with one side of Perspex sheet.
4. Measurements & Controls

v A Dimmerstat for heater input control.

v Voltmeter and Ammeter for heater input measurement.

v Multichannel digital temperature indicator.

A technical manual accompanies the unit.

SERVICES REQUIRED:

Bench area of 1.5m x 0,75m. at working height.

1. 230v, 5A, AC, electric supply with earthing connection.