GVC 3CC

GVC 3CC

FAN TEST UNIT – WIND TUNEL

Dimensions and gross weight: metres 2,0 x 2,0 x h1,8 Kg. 900

The educational centrifugal fan unit model G.V.C./3 C.C. has been designed and developed in view of executing tests and exercises related to the operation of a centrifugal fan as used in industrial applications, whose performance data and efficiency are similar to the values obtained from an identical equipment, however, greater in size and with a higher output rating. With the use of this educational unit, teachers are given sufficient means to make experiments directly on dynamics of air in a general way, as well as on centrifugal compressors in a more peculiar way, through the aid of flow rate and head values measuring instruments that are typical in modern industrial applications. As regards the unit's performance, due account has been taken of the measuring accuracy of power requirement, both of the fan and the electric motor, as well as of air speed measurement in the wind tunnel. These parameters allow, in fact, to achieve a precise meeting of the testing procedures for centrifugal fans.

CENTRIFUGAL FAN The fan model used in this assembly is characterized by the inlet cone nozzle and the intake disc of the toroidal-shaped fan. This kind of coupling ensures the air flow to be provided with the necessary continuity and absence of vortices, what represents the best premises to obtaining good efficiency along the entire performance diagram range.

MOTOR The electric motor is a DC unit with swinging-casing winding fed through a controlled diode power supply.

The swinging motor casing embodies a continuous torque detector and the torque reaction is visualized directly in Kgm. on a dial indicator. It is thus possible to know at any time the torque value expressed in Kgm: a schedule converts the power output in hp with respect to r.p.m. This measurements system is independent from the electro-mechanical efficiency of the drive motor. The power consumption of the electric motor can be determined by a voltmeter and an ammeter on the control board. The motor speed can be continuously varied within the range from 0 to 3.000 r.p.m. For any preset value between 0 and 3.000 r.p.m. speed remains stabilized at +/- 2 per cent when any variation occurs in load from 0 to 100 per cent and inversely, has well as variations of 10 per cent occur in the AC voltage supply.

I - 16153 P.D. da Bissone 36r. GENOA - ITALY - Tel.: +39 010 6501969 Fax: +39 010 6501969 e-mail: patrone@ giacomopatrone.com http://www.giacomopatrone.com

GVC 3CC

WIND TUNNEL The intake duct with a diameter of 350 mm and 500 mm long is fitted with a wheel controlled butterfly valve at its end, while a pressure tap is located downstream, to which a water differential manometer is mounted. The throw pipe is 300 mm in diameter and 3,100 mm in length . Upstream is fitted a fluid lines rectifier, which is preceded and followed by two static pressure taps. These are intended to allow for the measurement of load loss due to fluid friction with air inside the pipe. A Pitot static tube is secured after the fluid lines rectifier. This Pitot tube, of standard design to ISA specifications, is intended for measurement of air speeds and hence of flow rate, and it is installed to a graduated support that can be elevated vertically to make different level measurements in the line section. downstream the Pitot tube the outflow pipe gradually decreases in diameter, thus taking the shape of a standard Venturi meter, connected to a toroidal dial of the metering instrument required for the direct reading of air flow through the fan. The metering instrument is essentially built to meet educational requirements and the values obtained from it can be compared to those values obtained from the Pitot tube. This represents a very useful exercise and permits, at the same time, to check-out the accuracy degree of the dial measurement instrument. A further pressure tap, located at the duct, makes the instrumentation of this unit complete. At the end of throw pipe a second butterfly valve is mounted, and it can be controlled manually by means of a control hand-wheel.

CONTROL BOARD It consists of a metal cabinet housing the items listed below regularly connected and ready for operation: ¾ Line fuses ¾ Line switchgears ¾ Power supply consisting of a single-phase silicon rectifier bridge ¾ Electronic speed regulator ¾ Auxiliary circuits transformer ¾ Auxiliary cut-off switch for field protection.

The cabinet front mounts: ¾ One speed regulating potentiometer ¾ Two pushbuttons "START/STOP" with warning light ¾ Voltmeter ¾ Ammeter ¾ Tachometer ¾ Torque meter ¾ Master switch.

On the upper part of the cabinet is the control panel mounting the following items: ¾ Air flow meter ¾ Pitot tube differential pressure manometer ¾ Manometer for measuring the friction loss ¾ Inlet pressure measurement manometer.

TEST AND MEASUREMENTS PERFORMED WITH THE USE OF THE G.V.C.3/C.C. The unit allows for executing all testing processes concerning the inspection test of a centrifugal fan.

Therefore, the following testing operations are possible: ¾ Vacuum measurement at intake port ¾ Air flow rate measurement as a function of speed in r.p.m. ¾ Static pressure measurement ¾ Dynamic and total pressure measurement ¾ Friction loss measurement in the inlet and delivery ducts ¾ Determination of electric power requirement of the fan depending upon r.p.m. ¾ Torque value reading through transducer and differential transformer ¾ Determination of the fan efficiency at varying numbers of revolutions.

CONSTRUCTIVE DETAILS BEDDING The steel fabricated bedding mounting the centrifugal fan, the motor-generating unit and the torque meter, measures 1.250 mm in depth and 800 mm in length. ¾ Intake duct: 500 mm long ¾ Delivery duct: 3.100 mm long CENTRIFUGAL FAN DETAILS Intake bore diameter: 340 mm Max. Flow rate: Q = 5000 nm3/h Total pressure, max: ht = 100 mm H2O Speed, max.: N = 3125 RPM Max air speed at outlet: Vu = 20 mm/sec.

Power requirement at max speed: Pv = 1.8 kW MOTOR-GENERATING UNIT Power output: 3 hp at 3.000 r.p.m.

Armature voltage: 180 V. Exciting voltage: 190 V.

I - 16153 P.D. da Bissone 36r. GENOA - ITALY - Tel.: +39 010 6501969 Fax: +39 010 6501969 e-mail: patrone@ giacomopatrone.com http://www.giacomopatrone.com