Nederman FlexPAK DX, Installation And Service Manual

FlexPAK DX

short time after detection of the explosion (in milli-

seconds) and stops the pressure from rising and extin-

guishes (suppresses) the flames of the explosion.
This ensures that the filter is not stressed to a danger-

ous level by the explosion.
The key components of the explosion suppression

system are the following:
• An explosion detection device (optical/pres-

sure-sensitive).

• A computer-operated control unit.
• Action elements such as pressure cylinders contain-

ing an extinguishing agent with an extra fast open-

ing valve.

Detailed information regarding system installation,

function, operation and maintenance can be found in

the suppression system manual.

3.3.3 Flameless venting

The method of flameless venting is similar to method

1 “explosion venting”. However, a device attached to

the outside of the vent will stop flames from exiting

the filter vessel. Such a device is sometimes referred

to as a “quench-device” or “flameless-device”. See 

Fig-

ure 2C

.

Common for all types of flameless devices is that the

explosion is released through a specially designed grid

or mesh. The grid or mesh will allow pressure from an

explosion to be released but prevent the explosion’s

flames from exiting outside the filter vessel.
The benefit of using a flameless vent device is that

it reduces the size of the risk area. This increases the

possibility of positioning the FlexPAK DX closer to

manned areas or equipment.
However, it must be noted that the use of a flame-

less device does not eliminate the risk area. The high

pressure and hot gases are still released into the sur-

roundings, and this must be taken into consideration

when positioning the FlexPAK DX. Please consult your

local fire authority when determining suitable posi-

tioning of the FlexPAK DX with the flameless device.
Please refer to the installation and service or user

manual for the flameless device supplied with the

FlexPAK DX to find other limitations and information

regarding safe use and service.

3.3.4 Isolation device

An isolation device, see 

Figure 9

, item 2, is to be in-

stalled to prevent a filter explosion from propagating

back into the plant through the connected duct. The

duct, see 

Figure 9

 item 3, between the unit and the

isolation device, is to be pressure-resistant to an over-

pressure of at least 0,5 bar (7,2 psi) and have a minim-

um length as specified in the manual of the isolation
device. The volume for FlexPAK is 0,47m

3

 in the isola-

tion device. See also 

Section 3.5 Technical data

.

Duct isolation valve

The reverse air cleaning pulse of the FlexPAK

DX may cause the isolation device to close,

which would result in the unit not functioning.

Due to the cleaning pulse, in most cases, it is neces-

sary to install a damper upstream from the isola-

tion device. Install the damper either one meter or

five duct diameters from the isolation device in the

duct from workstations. See 

Figure 9

 item 1 and 

Sec-

tion 3.8 Connections

.

This is damper is called a duct isolation valve and it

must be closed during cleaning. It must also open

slowly so that the vacuum in the ducting system does

not cause a backflow through the isolation device. See

the PLC Settings Manual.

3.4 Dimensions

Figure 2C

 shows the dimensions of the inlet

and one side of FlexPAK DX.

For the dimensions of FlexPAK DX, see 

Figure 2A

, 

Fig-

ure 2B

, and 

Figure 2C

.

17