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1. Vacuum Gauges & Vacuum Valves
Defination:-
Instruments used to measure pressure are called
pressure gauges or vacuum gauges.
Type of Vacuum Gauges:-
1.Mechanical Gauges
2.U-Tube Manometers
3.McLeod Gauge
4.Capacitance Manometer
5.Pirani and Thermocouple Gauges

2. Figure 7.2: Mechnical Bourdon Gauge
Mechanical Gauges:-
Range from several atmospheres down to 0.1 Torr.(1
Torr=133.3 pa)
.

3. U-Tube Manometers
U-Tube Manometers:-
Range atmospheric to 0.2 Torr

4. McLeod Gauge :-
Range 10 torr to 10 -6 Torr

5. Capacitance Manometer or Di-aphragm
Gauge:-
Range 10+4 Torr to 10 -5 Torr

6. Pirani and Thermocouple Gauge :-
Range 100 Torr to 0.1 mTorr.

7. The three main functions of vacuum valves:-
•Isolate vacuum volumes from pumps
•Control gas flow to achieve a particular pressure
•Enable transfer of objects between vacuum volumes
A valve’s main design characteristics depend on
function, but details are determined by manufacturing
and user convenience. Construction materials include
stainless steel, aluminum, and brass—the choice
depending on the required bakeout temperature,
pressure range, and the construction material of the
remaining system.
Vacuum Valves

8. Type of Vacuum Valves:-
• Angle Valves
• In-Line Valves
• Ball Valves
• Butterfly Valves
• Leak Valves

9. Electromagnetic,Manual
Actuation Angle Valve
An angle valve is a fluid
regulating device used in
plumbing and industry. It has
inlet and outlet ports aligned
at an angle with respect to
each other, the most
common angle being 90
degrees. The inlet and outlet
ports can be threaded for
connecting to galvanized
steel and iron pipes.
Angle valve :-

10. Pneumatic Actuation In-
Line Valve
In-Line Valves:-
These valves share most
features and applications noted for
angle valves. The difference is one
port is turned 90° so its axis is
parallel with the other port’s axis.
This means the valve’s conductance
is reduced by the additional right
angle flow path.

11. Ball Valves:-
Ball valves are popular in many
gas and water applications but
less frequently found in
vacuum applications. They do,
however, provide low-cost,
rugged performance at rough
vacuum pressures are found
in foreline and trap
applications.

12. Butterfly Valves
Butterfly Valves:-
Butterfly valves are available in a range of sizes—large
size to small size use many foreline applications. A
popular application is as a down-stream conductance
controller to maintain a constant chamber pressure in
processes requiring gas flow.

13. Leak Valves: Leak valves are used to very accurately
control the flow of gas into a vacuum system from the external
source.
Leak valves have two specific applications:
(a) to admit gas into a vacuum chamber at a controlled leak
rate.
(b) to backfill a vacuum chamber to low pressure.
.