product for safe system from norgren

8/6/2019 Product for Safe System From Norgren

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Products for Safe Systems


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Legislation Problems

are solved with

a helping handand productsfor safesystems

Factory

InspectorateRisk

Assessment

MachineryDirective

EN Standards


4/29

Emergency stop valves EN 418 4.1.11 & 4.1.12

3/2 normally open valve

Large easy to operate redbutton

Once pushed the valve ismechanically latched on

Reset method options:

twist button

unlatch with a key


5/29

Two hand control EN 574 Two hand control

devices

Single fault tolerant Buttons must be pushed

in synchronisation

Output signal on only

while both buttons arepushed

If either button is releasedthe signal is lost so the

system must fail safe


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EN 983

Switching-on hazard


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Switching-on hazard Start from exhausted

system and cylinder at

mid stroke When air is turned on

there is no back pressureto control cylinder speed

Piston will slam to theend of stroke

Click the illustration to start and stop animation


8/29

Soft start valve Pressure is built up

gradually

Pre-exhausted cylinderswill move gently toposition

Snap point is reached

Full flow and pressure

Soft start valve output

10 20 30 40 50 60 70 80 90 1000

0

2

4

6

8

10

12

14

Time (seconds)

bar

snap point

10

1

2

3

12


9/29

Hazard solved System pressure is

re-applied

When the soft startvalve is turned on,flow is restricted sothat pressure builds

up gradually The cylinder will move

to the end of itsstroke gently



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EN 983

Switching off hazard


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Switching off hazard Emergency stop valve will

dump pneumatic power

Piston will outstroke dueto its load



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Passive piston rod lock Use a cylinder fitted with

a passive piston rod lock

Pressure normallyapplied to to hold the lockoff

When pressure is

dumped the lock springson to prevent movementunder load


13/29

Hazard solved Emergency stop valve

dumps air

Lock clamps the pistonrod

The load is supported



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Rodless cylinder with brake Rodless cylinder with a

passive brake to hold the

carriage in position


15/29

Blocking fittings Blocking fittings lock air

into a cylinder if the main

air supply fails Fitted directly to the

cylinder ports

Pressure applied to the

signal port holds thevalve open


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Blocking fittings When the supply air is

removed the two blocking

fittings spring closed The cylinder will stop

A load will be held inbalance



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Further Safety Products for EN 983


18/29

Pressure relief valves EN 983 5.1.2

Protection against over

pressurisation Air relieved or dumped

Adjustable relief pressure

Exhaust can be piped

away to prevent a hazard


19/29

Tamper-resistant kits EN 983 5.3.5.2

For pressure regulators

and lubricators Tamper resistant clamps

to prevent useradjustment

Can be wired and sealedor padlocked


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Locking ball valve EN 983

Shut off ball valve

Isolates upstream supplypressure

Exhaust feature vents thedownstream pressure

Can be locked in theclosed position with apadlock

Cannot be locked in the

open position


21/29

Silencers EN 983

Exhaust port silencers

Heavy duty robustconstruction to withstandknocks and abrasion

Efficient noise reduction

Wide range of port sizes External and internal

threads


22/29

Coalescing exhaust silencer EN 983 5.1.9.

All exhausts from a

system can be piped toone or more of theseunits

The sub-micron element

removes oil mist andsolid particles

Continuous draining of oilto collection bowl

Dramatically reducesexhaust noise


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Other Safety Products


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Pre-set pressure regulators Pressure reliably held and

not user adjustable

Supply to blow guns andbreathing air sets aretypical examples

The miniature regulator

shown is factory pre-setand sealed in a tamperresistant housing


25/29

Air fuse An air fuse is fitted at the

supply end of a hose

Will detect a severedhose or failed joint

Air flow is automaticallyclosed down to prevent

the hose from whippingabout


26/29

Blow guns Limited width central air

jet

Wide surrounding jet tominimise particle blowback

Vent holes to spill air if

the nozzle is placed tooclose to the skin or otherobject

Supply only with cleandry un-lubricated air


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Monitored dump valve Monitored Dump Valve

(MDV) is a 3/2 solenoid

operated valve Used to dump air for

safety critical systems

Incorporates a switch to

monitor the position ofthe valve spool

Monitoring can beperformed by a Pilz safetyrelay


28/29

Monitored dump valve Door closed, air supply on

Door open, air dumped

If the spool of one of thedump valves jams on, theair will be dumped by theother

The faulty valve will notremake the monitoring loop

The safety relay will notenergised either valve againuntil the faulty valve isreplaced



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End

product for safe system from norgren

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