contains info about different spool actuation methods

1. SPOOL ACTUATION METHOD
BY :
SANGAM KAUSHIK
SAMYAK JAIN
SHRENIK BAID

2. PREFACE
 Introduction
 Type’s of valves
 Directional control valve
 Necessity of DCV
 Types of Spool
 Types of Spool Actuating Methods
 Advantages of valves

3. INTRODUCTION
 One of the most important considerations in any fluid power system is
control. If control components are not properly selected, the entire
system does not function as required. In fluid power, controlling
elements are called valves.

4. Types of Valves
 There are three types of valves:
I. Directional control valves (DCVs): They determine the path through which a
fluid transverses a given circuit.
II. Pressure control valves: They protect the system against overpressure, which
may occur due to a sudden surge as valves open or close or due to an increase
in fluid demand.
III. Flow control valves: Shock absorbers are hydraulic devices designed to
smooth out pressure surges and to dampen hydraulic shock

5. Directional control valve
 A valve is a device that receives an external signal (mechanical, fluid pilot
signal, electrical or electronics) to release, stop or redirect the fluid that
flows through it. The function of a DCV is to control the direction of fluid flow
in any hydraulic system. A DCV does this by changing the position of internal
movable parts .
 Directional control valves are one of the most fundamental parts in hydraulic
machinery as well as pneumatic machinery. They allow fluid flow into
different paths from one or more sources. They usually consist of a spool
inside a cylinder which is mechanically or electrically controlled. The
movement of the spool restricts or permits the flow, thus it controls the fluid
flow.

6. Necessity of DCV
 To start, stop, accelerate, decelerate and change the direction of motion of a
hydraulic actuator.
 To permit the free flow from the pump to the reservoir at low pressure when
the pump’s delivery is not needed into the system.
 To vent the relief valve by either electrical or mechanical control.
 To isolate certain branch of a circuit .

7. PCV (PRESSURE CONTROL VALVE)

8. FCV (FLOW CONTROL VALVE)

9. Types of spool
Spool
Sliding
Rotary

10. Sliding spool
 Sliding spool is cylindrical in cross section, and the lands and grooves are also
cylindrical . This consists of a specially shaped spool and a means of
positioning the spool. The spool is fitted with precision into the body bore
through the longitudinal axis of the valve body. The lands of the spool divide
this bore into a series of separate chambers. The ports of the valve body lead
into these chambers and the position of the spool determines the nature of
inter-connection between the ports.

11. Rotary spool
 Rotary valves have sphere-like lands and grooves in the form of holes drilled
through them . In this type, the spool is rotated to change the direction of
fluid. It has longitudinal grooves. The rotary spools are usually manually
operated.

12. Types of Spool Actuating Methods
 Manual
 Mechanical
 Solenoid
 Hydraulic
 Pilot
 Electric
 Fluidic
 INDIRECT

13. A. Manually operated
 In manually operated DCVs, the spool is shifted manually by moving a handle
pushing a button or stepping on a foot pedal. When the handle is not
operated, the spool returns to its original position by means of a spring
B.Mechanically Operated
 The spool is shifted by mechanical linkages such as cam and rollers .
C. Solenoid operated
 When an electric coil or a solenoid is energized, it creates a magnetic force
that pulls the armature into the coil. This causes the armature to push the
spool of the valve .
D. Pilot operated
 A DCV can also be shifted by applying a pilot signal (either hydraulic or
pneumatic) against a piston at either end of the valve spool. When pilot
pressure is introduced, it pushes the piston to shift the spool.

16. Advantages
 Innovative
 Small and compact for a wide range of pneumatic applications .
 Low weight
 Minimal actuating forces .
 Versatile
 Round silencer for ducted exhaust air
 Suitable for vacuum in some cases
 Reverse operation possible in some cases
 Actuation: direct and piloted
 Reliable

19. Q.1 What is the function of DCV?
A DCV is the extend & retract control for your hydraulic cylinder.It provides a
flow path from the pump to the cylinder and a return path from the cylinder to
the fliud reserviour .
Q.2 Why are Control valves sometimes very noisy?
Noise is generated whenever there is a unbalanced system . In valves,
noise is generated because of vibration produced due to very high
velocity turbulent flow and even also on high pressure drop.
To overcome this, speacial low noise valves are designed to drop pressure
gradually so that velocities are controlled at low levels.

20. Q.3 Is flow through the control valve –
laminar or turbulent?
Flow throught the control valve is almost always turbulent.

21. THANK YOU