Groth 7758A - Manual (Page 3)

Groth model 7758A stable detonation flame
arresters were tested with one Groth integrated
temperature sensor, P/N 93219005, installed on
the ignition side. All arresters are manufactured
with a minimum of either one thermowell or one
thermocouple port, positioned to align the
thermocouple with the face of the element.
Multiple thermowells or ports may be on one or
both faces as specified by the purchaser. Groth
temperature sensors may also be installed as
specified.
If the purchaser installs an integrated
temperature sensor, it must be an ATEX
approved devise, installed in the Groth
thermowell such that the sensor contacts the
bottom of the thermowell.
DESIGN AND FUNCTION
Groth's detonation flame arresters are proven to
prevent flame propagation in gas piping systems
which contain flammable gas/vapor mixtures. The
arrester must prevent flame passage under certain
specified conditions while permitting free flow of
gas/vapor through the system. Thus it protects
vulnerable equipment or components of the system
from damage due to explosive pressures caused by
gas/vapor ignition in another part of the system.
The detonation flame arrester must be used under
only those operating conditions for which it was
designed and tested.
The flame arresters consist of two main
components, the arrester bases and the flame
element housing assembly. The bases serve as
the connecting interface to the piping system. The
housing retains and supports the flame element.
Both components are essential in stopping the
passage of the flame.
The flame element consists of multiple layers of
stainless steel wire cloth, laminated and sintered
into a strong, ductile, corrosion resistant and
uniform sheet. The sheets are cut to various sizes
and fit into cylindrical steel housings. The element
is supported by rigid beams, securely welded into
the housing to withstand the extreme pressures of
an overdriven detonation. Each nominal size
arrester can be supplied with various diameter
elements to provide the required flow capacity.
The bases must also withstand the detonation
pressures while conveying the burning vapors and
flame front to the element. Depending on the
design of the system in which it is used, the arrester
bases can include optional ports for thermocouples
or pressure monitoring devices. These devices can
activate warning or shutdown systems if abnormal
conditions are detected. Both bases may be
equipped with large diameter inspection/clean-out
ports for in-line maintenance of the element. If
element removal is required for inspection,
maintenance or replacement see maintenance
instructions.
Note
A short time burning detonation flame
arrester cannot withstand a continuous flame,
and must have a flame monitoring system
capable of shutting down the vapor flow
within a specified time.
WARNING
A detonation flame arrester may be exposed to
instantaneous pressure spikes in excess of
1000 PSI. Any instrumentation attached to
the arrester must be capable of continued
operation in this environment.
INSTALLATION
Operating Conditions:
Based on the testing conditions, Groth Model
7758A detonation flame arrester may be installed in
piping systems where:
1. The MESG of the vapor constituent(s) is greater
than or equal to 0.025" (0.65 mm).
2. System operating pressure is less than or equal
to the nameplate pressure [see test results,
page 1].
3. Normal operating temperature is between -
13 o F (-25 o C) and 140 o F (60 o C).
4. The piping system in which the detonation
arrester is to be installed must not exceed the
arrester flange size.
WARNING
IOM-7758A
Ref. ID 97895
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