HJC黄金城

Description

A bench top unit designed to introduce students to the characteristics of saturated water vapour.
The apparatus is equivalent to a Marcet Boiler, with an additional throttling calorimeter and a pipe loop, which enables saturated steam to
be returned to the base of the boiler as condensate.
Pure water in the boiler is heated to its boiling point using a pair of cartridge heaters with variable power control. A sight glass on the front
of the boiler enables the internal processes to be observed, namely boiling patterns at the surface of the water, and also permits the water
level in the boiler to be monitored.
Saturated steam leaving the top of the boiler passes around the pipe loop before condensing and returning to the base of the boiler for
reheating. The operating range of the boiler and loop is 0 - 7 bar. The top limb of the pipe loop incorporates a Platinum Resistance Thermometer
(PRT), temperature sensor and an electronic pressure sensor to measure the properties of the saturated steam. A flling point on the top limb
enables the loop to be flled with pure water and permits all air to be vented safely before sealing the loop for pressurised measurements.
A vapour offtake, with isolating valve, enables steam from within the loop to be passed through a throttling calorimeter, the purpose of which
is to demonstrate how the dryness fraction of the saturated steam in the loop can be determined.
The steam expands to atmospheric pressure as it is throttled and a second PRT temperature sensor measures the temperature of the
steam following expansion.
The apparatus is designed for safe operation with a pressure relief valve set to operate if the pressure rises above the working pressure and a
Bourdon gauge that remains operational when power is disconnected from the electrical console.
All power supplies, signal conditioning, circuitry etc. are contained in anelectrical console with appropriate current protection devices and an
RCD for operator protection. Readings from the sensors are displayed on a common digital meter with selector switch and all corresponding
signals are routed to an I/O port for connection to a PC using an optional parallel interface/educational software package.