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DR/ES (series 2)

In-Line Detonation Flame Arrester for stable detonations and deflagrations in right angle design with shock absorber, unidirectional

  • minimum number of FLAMEFILTER® discs due to the effective shock absorber
  • quick removal and installation of the complete PROTEGO® flame arrester unit and FLAMEFILTER® discs in the cage
  • due to modular design the FLAMEFILTER® discs can be individually replaced
  • the right angle design saves pipe elbows
  • extended application range for higher operating temperatures and pressures
  • high flow performance at small flange connection
  • minimum pressure loss and hence low operating and lifecycle cost
  • cost efficient spare parts

Function and Description

The PROTEGO® DR/ES in-line detonation flame arrester has been used for decades in industrial plant construction because its right angle design offers advantages towards maintenance and costs in comparison to most straight designs.

Once a detonation enters the device, energy is absorbed from the detonation shock wave by the integrated shock absorber (1) before the flame is extinguished in the narrow gaps of the FLAMEFILTER® (3).

The PROTEGO® flame arrester unit (2) consists of several FLAMEFILTER® discs and spacers firmly held in the FLAMEFILTER® cage (4). The gap size and number of FLAMEFILTER® discs are determined by the operating data of the mixture flowing in the line (explosion group, pressure, temperature). This device is approved for explosion groups from IIA to IIB3 (NEC group D to C MESG ≥ 0.65 mm).

The PROTEGO® DR/ES series 2 was developed for higher flow performance at small flange connection. It is approved at an operating temperature up to +60°C / 140°F and an absolute operating pressure up to 1.2 bar / 17.4 psi. Devices with special approvals can be obtained for higher pressures and higher temperatures upon request.

Type-approved in accordance with the current ATEX Directive and EN ISO 16852 as well as other international standards.


To select the nominal size (DN), please use the flow capacity charts on the following pages

DN50 / 2"80 / 3"100 / 4"
NG80 / 3"100 / 4"150 / 6"
a200 / 7.87250 / 9.84335 / 13.19
b225 / 8.86290 / 11.42360 / 14.07
c365 / 14.37440 / 17.32535 / 21.06
c1500 / 19.69595 / 23.43750 / 29.53
d275 / 10.83325 / 12.80460 / 18.11
e705 / 27.76795 / 31.30950 / 37.40
Dimensions in mm / inches

Material selection for housing

HousingSteelStainless Steel
Heating jacket (DR / ES-H-(T)-...)SteelStainless Steel
Cover with shock absorberSteelStainless Steel
Flame arrester unitAB, C, D
* for devices exposed to elevated tem- peratures above 150°C / 302°F (T150), gaskets made of PTFE. The housing and cover with the shock absorber can also be delivered in steel with an ECTFE coating. Special materials upon request

Material combinations of flame arrester unit

FLAMEFILTER® cageSteelStainless SteelStainless SteelHastelloy
FLAMEFILTER®*Stainless SteelStainless SteelHastelloyHastelloy
SpacerStainless SteelStainless SteelHastelloyHastelloy
* the FLAMEFILTER® are also available in the materials Tantalum, Inconel, Copper, etc. when the listed housing and cage materials are used. Special materials upon request

Selection of explosion group

MESGExpl. Gr. (IEC / CEN)Gas Group (NEC)
> 0,90 mmIIAD
≥ 0,65 mmIIB3
Special approvals upon request

Selection of max. operating pressure

DN50 / 2"80 / 3"100 / 4"
NG80 / 3"100 / 4"150 / 6"
Expl.Gr.IIAPmax1,6 / 23.21,6 / 23.31,6 / 23.4
Expl.Gr.IIB3Pmax1,6 / 23.31,5 / 21.71,4 / 20.3
Pmax = Maximum allowable operating pressure in bar / psi absolut, higher operating pressure upon request

Specification of max. operating temperature

≤ 60°C / 140°FTmaximum allowable operating temperature in °C
higher operating temperatures upon request

Flange connection type

EN 1092-1; Form B1
ASME B16.5 CL 150 R.F.
other connections upon request

Design Types and Specifications

There are four different designs available:

Basic in-line detonation flame arrester

DR/ES- – - –

In-line detonation flame arrester with integrated temperature sensor* as additional protection against short time burning

DR/ES- T - –

In-line detonation flame arrester with heating jacket

DR/ES- H - –

In-line detonation flame arrester with integrated temperature sensor* against short time burning and heating jacket

DR/ES- H - T

*Resistance thermometer for device group II, category (1) 2 (GII cat. (1) 2)

Flow Capacity Chart

The flow capacity charts have been determined with a calibrated and TÜV certified flow capacity test rig. Volume flow V in (m³/h) and CFH refer to the standard reference conditions of air ISO 6358 (20°C, 1bar). For conversion to other densities and temperatures refer to Sec. 1: “Technical Fundamentals”.