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Axial Flow Regulators

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Axial Flow Regulators

Compact in-line regulators that

sandwich between two flanges.

Capable of passing high volumes

of gas using external pilot

regulators to control the opening

and closing of a rubber sleeve.

The sleeve effectively acts as a

combined diaphragm and valve -

providing both sensing and

control.

The unit can be used as a

pressure regulator or relief valve.

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Axial Flow Regulators - Main Components

This diagram shows an

assembly of:

• Axial Flow Valve

• Inspirator Block &

• ZSC 100 Pilot

The following slides look at

these three items in turn.

An alternative Restrictor

Block is also available for

specialist industrial

applications where fast

response is required.

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Axial Flow Valve - Sub Components

The main regulator comprises a very simple set of components.

Upstream and downstream cages are interchangeable. This symmetry has the

result that the axial flow valve will control in both directions, although strictly the

fairing nut should be at the downstream side for flow smoothing.

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1. With gas supply pressure at

the back of the sleeve equal to

inlet pressure the sleeve is

closed against the inlet cage. A

closing force equal to inlet

pressure acts on the

downstream ‘V’ sleeve area

forcing it against the

downstream cage to give

double closure and completely

tight seal.

2. Reducing the pressure at the

back of the sleeve creates a

pressure imbalance across the

sleeve, inlet pressure now being

higher. This expands the sleeve

away from the cages thereby

allowing flow from inlet to outlet.

The pressure at the back of the

sleeve can now be referred to as

the ‘Control’ Pressure.

3. Reducing the control

pressure further increases the

differential across the sleeve

allowing it to expand further

until the sleeve is flat against

the body for 100% capacity.

The position of the sleeve and

therefore flow is controlled by

the pressure at the back of the

sleeve.

Axial Flow Valve - Operation

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Axial Flow Regulators - Inspirator Block

This block includes an

inspirator that acts in the

conventional manner.

The Venturi effect causes the

control pressure to reduce as

flow through the inspirator

increases. (It is this reduction in

control pressure that allows the

sleeve to “open”.)

The adjustable restrictor allows

regulator performance to be

tuned to improve control.

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Axial Flow Regulators - ZSC Pilot

The spring loaded pilot, shown

here, is spring biased open.

Note that the pilot does not load

the regulator but acts like an

auxiliary K regulator drawing

more flow through the inspirator

as demand increases.

The ZSC pilot is also available

as a relief valve, although for

this service must be reverse

acting e.g. spring biased closed.

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Axial Flow Regulators - Position Indicator

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Axial Flow Regulators - Configurations

Axial flow regulators are usually configured as monitor/active or two stage/monitor

override systems.

This diagram shows the latter two stage/monitor override arrangement, installed

with restrictor control rather than the more conventional inspirator.

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Key Advantages

Very compact

Greater capacity ‘size for

size’

Simple in construction and

operation

Reliable and easy to

maintain

A wide range of application

using one common design

A proven, low risk design

Lower noise level

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Versatility

Pressure reduction from 100 bar down to 30 mbar

Active or monitor mode

Two stage pressure cut

Volumetric flow control

Over and under pressure shut off

Back pressure/relief valve

Pulsating dampening

Remote control via pneumatic or electronic signal

Can be installed in any position

Low operating differential

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P1

P1

Falling

Outlet

Pressure

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Quiet Axial Flow Regulator Components

Bolt Washer

Interchangeable

valve cage

closure Valve body Rubber sleeve

single working part

Interchangeable

valve cage

closure

Washer Fairing nut

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Pilots and Control Blocks

Restrictor Blocks

Inspirator Blocks

ZSC100 Pilot

1203EP Pilot

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Control Systems Differences

F F

P1 P2 P1 P2

Pilot Pilot

Inspirator

control

Restrictor

control

Restrictor