Tesca Saturation Vapour Pressure Apparatus has been designed to introduce students to how the temperature of water behaves at its boiling point with variation in the absolute pressure. Saturation curves can be obtained by the student and compared with published steam tables. The quality of steam exiting the apparatus can be determined using a throttling calorimeter connected at the point of discharge.

Features
1. Measurement of the relationship between temperature and pressure of the saturated vapour in the loop
2. Convenient control of heat input to the boiler using variable power control
3. Sight glass in the boiler allows observation of the boiling patterns in the water
4. Safe operation with pressure relief valve and permanent indication of system pressure
5. Pressure and temperatures measured can be logged using a PC (optional teaching software available)

A bench top unit designed to introduce students to the characteristics of saturated water vapour. The apparatus  consists  of  a  rectangular pipe loop incorporating a cylindrical boiler in one vertical limb. 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 allows the internal processes to be observed, namely boiling patterns at the surface of the water, and also allows 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 re-heating. The operating range of the boiler and loop is 0 to 7 bar gauge. The top limb of the pipe loop incorporates a PRT temperature sensor and an electronic pressure sensor to measure the properties of the saturated steam. A filling point on the top limb allows the loop to be filled with pure water and allows all air to be vented safely before sealing the loop for pressurized measurements. A vapour offtake, with isolating valve, allows 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 an electrical 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

Specifications
A bench top unit comprising a boiler vessel and pipe loop with a pressure relief valve to limit the operating pressure to 8 bar gauge. A sight glass on the front of the boiler allows the boiling patterns to be observed and a Bourdon type gauge indicates the pressure in the apparatus at all times for safe operation.
A throttling calorimeter mounted adjacent to the pipe loop allows the condition of the saturated steam to be deter mined by measuring the temperature of the steam following throttling to atmospheric pressure. Temperatures in the pipe loop  and  inside  the  throttling  calorimeter are measured using PRT sensors and pressure in the loop is measured using an electronic pressure sensor.
An electrical console houses the necessary electronics with current protection devices and an RCD for operator protection. A digital meter with selector switch displays all sensor measurements. Corresponding signals are routed to an I/O port for connection to a PC. An optional interface device and educational software package is available.
The boiler is heated by a pair of 500 W electric heating elements with variable power control and over-temperature protection.
A comprehensive instruction manual is included with a range of fully detailed laboratory teaching exercises.
Apparatus at different operating pressures.
Use of the steady flow energy equation
The two property rule
Use of steam tables
The  difference  in  enthalpy  between  phases  - enthalpy of vaporization

Technical Specification
Heating Tank
Capacity: 2 Liters
Material:
Stainless steel
c/w sight glass
Pressure Gauge
Type: Bourdon type
Range: 0 to 100 psi
Temperature sensor
Range: 0 to 200
Instrumentations
Temperature sensor with indicator
Transducers: Temperature and pressure
Safety: Temperature controller; pressure relief valve

Experimental Capabilities
Teaching exercises will enable students to become familiar with the following topics: Saturation Loop:
Observation of the patterns of boiling at the surface of the water
Measurement of the temperature of saturated steam over the range of pressures 0 to 7 bar gauge and comparison of the saturation curves obtained with those published in steam tables.
The concept of a saturation line
The describing equation and linearization
Gauge and absolute pressures
Temperature scales
The characteristic behavior of a two phase fluid
The effect of rate of response on the accuracy of measurement

Throttling Calorimeter
Determination of the condition of the wet steam (quality of the steam) produced by the Saturation Pressure