AIR COMPRESSOR TEST RIG

AIM:

To conduct a test on two stroke two stage air compressor and to determine the mechanical efficiency and isothermal efficiency at various delivery pressure.

DESCRIPTIONTwo Stage Compressor is a reciprocating type driven by a prime mover AC motor through belt. The test rig consists of a base on which the tank (air reservoir) is mounted. The outlet of the air compressor is indicated by a thermometer and pressure gauge. The electrical safety valve is provided and also a mechanical safety valve is provided as an additional safety valve is provided for an additional safety. The suction is connected to the air tank with a calibrated orifice plate through the water manometer. An energy meter records the input to the motor.

PROCEDURE The outlet valve is closed

The manometer connections are checked. The manometer is filled with water up to the half level.

The compressor is started and note down initial energy meter reading and spring scale reading.

The tank pressure gauge is read for a particular pressure.

Note down the rpm of the compressor

Note down the manometer reading.

Reading of energy meter

Repeat the experiment for various pressure

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CALCULATIONS

w01. HNTP = hm = h x -------- a

w = Density of water = 100 kg/m³a = Density of air = 1.283 kg/m³ h = Manometer reading in mm

02. DENSITY OF AIR AT R.T.P. a x 273

Air density at R.T.P. = -------------------------- Kg/m³ 273 + room temp.

03. ACTUAL VOLUME OF AIR DRAWN AT RTP CONDITION w

Va = Cd x A x 2gh ------- m³/sec a

Where Cd co-efficient of discharge = 0.62 (d) ²

Area of correction of orifice = ----------- in mtrs² 4

d = Dia of orifice = 17 mm (0.017 mtrs.) w

h = (ha -------- ) in mtrs a

a = 1.193 kg/m³ (density of air)

w = 1000 kg/m³ (density of water)

ha = manometer reading in mtrs

Engineering Equipment Enterprises, Coimbatore – Bangalore - Ghaziabad

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04. SWEPT VOLUME = Vs

NcVs = -------- (d) x L x ------ in m³ / sec

4 60

D is dia of piston = 0.063 in mtr

L is stroke length = 0.087 in mts.Nc is speed of the motor in rpm (1400 RPM constant at all load condition)

05. VOLUMETRIC EFFICIENCY IN %

Va Vol = -------- x 100

Vs

06. BRAKE HORSE POWER:

2 x x N x TBHP = ---------------------

4500

N = Motor speed in rpm (1400 rpm constant at all load condition)

T = Torque in kg – mtrs T = (s x r)s = spring balance reading in kgr = radius of the arm 0.23 in mtrs

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07. ISOTHERMAL HP :

Pa x Va= --------------- loge 75

Pa = Atmospheric pressure in kg/cm² (1 kg/cm² = 1 x 10 ⁴ kg/cm²)

Va = Actual volume of air in take in m³/sec

08. ISOTHERMAL EFFICIENCY IN %

ISOTHERMAL HP Iso = ---------------------------- x 100

BHP

09. POWER IN PUT TO THE MOTOR

No. of rev energy meter x 3600P = --------------------------------------------------------------------------- in HP

Time taken for the rev. x energy meter constant x 736

10. EFFICIENCY MOTOR IN %

BHP ------------ x 100 = motor P

11. BHP OF COMPRESSOR

BHP of the motor x transmission efficiency

Transmission efficiency = 80% = 80Engineering Equipment Enterprises, Coimbatore – Bangalore - Ghaziabad

TRIPLEE

MANUAL FOR

AIR COMPRESSOR TEST RIG

BLOWER TEST RIG

AIM :

To conduct a test on blower and to determine the overall efficiency.

DESCRIPTION The blower is single stage centrifugal type. The air is sucked from atmosphere from suction side. The slightly compressed air passes through the spiral case, before it comes out through the outlet.

Blower are used to discharge higher volumes of air at low pressures. The blowers are used in blast furnaces, cupolas, mines, air conditioning plants, etc. The three types of impellers namely (a) backward curved (b) Radial and (c) Forward curved (Red, Yellow and back respectively) can be fixed intern at a time.

The blower consists of the impeller fabricated to the shapes as per our drawing. The vanes of the impeller is pressed out a sheetmetal and riveted to the two shrouds thus forming into a unique unit. The other impellers are also fabricated in similar fashion and are easily mountable on the shaft. The casing is made of cast iron. The whole contour is volute in shape. The smooth contour helps in reducing eddy current losses along the path. The casing is designed such that it can be separated to facilitate mounting or interchanging of impellers.

The shaft is coupled to a motor which intern supported in the bearing block. The reaction excerted due to rotation can be measured by the spring balance and hence the input to the blower.

The flow at inlet and the exit is measured by the manometer. The whole probe can be actuated by the screw mechanism. This render to draw the profile of the velocity along the diameter of the pipe.

Engineering Equipment Enterprises, Coimbatore – Bangalore - Ghaziabad

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Pitot tube used to find out the dynamic and static pressure in delivery side orifice, meter used to find out dynamic pressure in suction side and ventury used to find out the quantity of flowrate, with mercury manometer.

PROCEDURE

Close the gate valve of the blower provided.

Star the motor using starterNow open the gate valve desired flowTake manometer readings or orifice, ventury , pitot tube and pressure dropMeasure speed of the motor using hand tachometer and corresponding spring balance reading.Measure the power consumed by the motor using energy meter corresponding to the time.

The various stages of opening of valve and corresponding readings mentioned above can be taken changing different in colours also Efficiency over all increases with the increase in output. At low outputs the efficiency is small since the head causing the flow if air and volume of air is less considerable.

BLOWER CALCULATIONS

01. Power input to the motor

No. of revolution x 3600= ------------------------------------------------------- = hp

time taken ins ec x 0.736 x e/m constant

02. Total delivery head in terms of air (Pitot tube ) Hm 1

Density of mercury – density of air= Hm1 = H1 x ---------------------------------------------------------- density of air

H1 = manometric difference in meters of mercury

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03. Suction head in terms of air (orifice meter ) = Hm2 p Density of mercury – density of air

= H2 x ------------------------------------------------------ Density of air

H2= Manometric difference in meters of mercury

04. Total head of venturimeter in terms of air (Hm3) =

Density of mercury – density of air= Hm3 = H3 x ---------------------------------------------------------- density of air

H3 = Manometric difference in meters of mercury

05. Actual volume flow of air

Va = Cd x K x Hm3 x 2g m³ /sec

WHERE Cd = 0.92

A1 x A2K = ----------------------

A1² - A2²

g = 9.81 m / sec²

Density of air x Va (Hm1 + Hm2)06. Out put of blower = ------------------------------------------------ HP 75

Output07. Efficiency of blower = ------------------- x 100 = % Input

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OBSERVATIONS Note down the readings

For different gate opening and blower blades

01. Density of 1.293 kg /mts³

02. Density of Hg 13,600 Kg/m³

D1²03. Area of inlet A1 = ----------- Where D1 = 152.4 mm 4

D2²04. Area of throat A1 = ----------- Where D2 = 101.6 mm 4

TABULAR COLUMN

------------------------------------------------------------------------------------------------------------------ Sl. Ventury Pitot Orifice Energy Rpm Spring No. head tube head meter of balance

In cms head in cm reading motor readingOf Hg in cm Hg Hg