A gate valve uses a wedge-shaped gate that allows fluid flow when lifted off its seat. Gate valves have less resistance to flow than globe valves and should always be fully open or closed. There are two main types - parallel gate valves which use a flat disc between parallel seats for low pressures, and wedge-shaped valves which use inclined seats and gate for tight shut-off. Gate valves are commonly used in air, fuel gas, feedwater, steam, and other piping systems due to their good shut-off characteristics, bi-directionality, and minimal pressure loss through the valve. However, they are not quick opening/closing and require more space than other valves.
2. DEFINITION OF GATE VALVE
A valve utilizing a gate,
usually wedge-shaped,
that allows fluid flow when
the gate is lifted from
the seat. Gate valves have
less resistance to flow
than globe valves, and
should always be used
fully open or fully closed.
4. WORKING OF GATE VALVE
When handle wheel will be
rotated in anticlockwise
direction.
The steam and gate will
move in downward direction.
The fluid flow line and gate
will be tightly located
between the two seats.
Hence there will be not not
any leakage of fluid through
the valve once valve is
closed completely.
5. WORKING OF GATE VALVE
When handle wheel will be
rotated in anti clockwise
direction.
The steam and gate will
move upward direction.
The fluid flow line and valve
will be open once the gate
valve is completely open.
The fluid is move in the
valve freely.
6. TYPES OF GATE VALVE
Gate valves are usually
divided into two types
1.parallel gate valve
2.wedge-shaped gate valve
7. TYPES OF GATE VALVE
1.Parallel gate valve:
The parallel gate valve
uses a flat disc gate
between two parallel
seats, upstream and
downstream. Parallel
gate valves are used in
low pressure drops and
low pressures, and
where tight shutoff is not
an important
prerequisite.
8. TYPES OF GATE VALVE
2.wedge-shaped gate valve:
Wedge-shaped gate valves use two
inclined seats and a slightly mismatched
inclined gate, allowing for tight shut-off.
Solid wedges are the most common
because of their simplicity and strength.
They can be installed in any position,
are suitable for almost all fluids, and are
practical for turbulent flow. Flexible
wedge gate valves are commonly used
in steam systems. The disk is one piece
with a cut around the perimeter to
improve the ability to match error or
change the angle between the seats.
9. APPLICATIONS OF GATE VALVE
Gate valves in air, fuel gas, feedwater,
steam, lube oil, and other systems are typical
applications of Gate valve.
Fire protection systems’ water piping or
water distribution pipelines,gate valves are
commonly used.
10. ADVANTAGES OF GATE VALVE
They have good shutoff characteristics.
They are bidirectional.
The pressure loss through the valve is
minimal.
11. DISADVANTAGES OF GATE VALVE
Gate valves are not quick opening or closing
valves.
Gate valves require large space for
installation, operation.
Repair or machining of valve seats in place is
difficult.