Knitted Wire Mesh Demister Pad | China Factory/exporter

How does a demister pad work ?

The demister pads work by coalescing smaller liquid droplets by obstructing their path. Obstruction of path causes increased collisions among the liquid droplets. Most of these droplets stick together and form bigger droplets which are too heavy to rise with the gas stream. Thus the bigger liquid drops drop down in the pool of liquid below. Gas stream is not affected by the obstruction in the path and escapes through top vapor outlet. The obstruction in the path of liquid droplets can be achieved by a variety of geometries. Demister pad may be a mesh type coalescer, vane pack or other structure intended to aggregate the mist into droplets that are heavy enough to separate from the vapor stream.

Maintenance of demister pad

After using for a long time, the demister pad will clog or prone to flooding and the pressure drop will increase. All these because of the particles in the gas blocks the demister pad. So you need maintain the demister pad properly and regularly.

Maintenance method: clean the demister pad. As we all know, the dilute acid on the demister pad will shorten the service life of demister pad, so we should place the demister pad in the natural state or under the sunlight

Selected wire mesh form

Selected demister pad forms have four categories: standard type, efficient type, high penetration type and shock absorber type.

Specifications of standard type demister pad

Item	Wire type	Wire size (mm)	Wire width tolerance (mm)	Bulk density (kg/m3)	Specific surface area (m2/m3)	porosity
STWM-01	Flat wire	0.1 �� 0.4	+10/-0	150	475	0.981
STWM-02	Round wire	0.23			320
Note: every 100 mm thick mat has 25 layers wire mesh.

Specifications of efficient type demister pad

Item	Wire type	Wire size (mm)	Wire width tolerance (mm)	Bulk density (kg/m3)	Specific surface area (m2/m3)	porosity
ETWM-01	Flat wire	0.1 �� 0.3	+10/-0	182	626	0.977
ETWM-02	Round wire	0.19			484
Note: every 100 mm thick mat has 32 layers wire mesh.

Specifications of high-penetration type demister pad

Item	Wire type	Wire size (mm)	Wire width tolerance (mm)	Bulk density (kg/m3)	Specific surface area (m2/m3)	porosity
HTWM-01	Flat wire	0.1 �� 0.4	+10/-0	98	313	0.9875
HTWM-02	Round wire	0.23			4217
Note: every 100 mm thick mat has 20 layers wire mesh.

Specifications of shock absorber type demister pad

Item	Specification	Filament specifications (mm)
STWM-01	33-30 type	0.08
STWM-02	38-40 type	0.08
STWM-03	20-40 type	0.22
STWM-04	30-40 type	0.1/0.12
STWM-05	30-50 type	0.16
STWM-06	40-60 type	0.12
STWM-07	30-80 type	0.22
STWM-08	50-120 type	0.22
STWM-09	40-120 type	0.22

Chinese standards

Wire mesh demister pad domestic standards are divided into HG5-1404 (1405, 1406) - 81, HG/T 21618-1998, HG/T 21586-98.

HG5-1404(1405, 1406)-81

The standards are divided into the riser-type (1404), the necking type (1405) and full bore type (1406).

The diameter of demister is from 300 mm to 6400 mm and height is 100 mm and 150 mm.

Mark example: HG5-1406-81-11, 304 refers to the 304 stainless steel of grating and wire mesh, dull bore coat type, 1600 mm diameter, 100 mm height demister pad.

HG/T 21618-1998

New standard merges riser type, reducing necking type and full bore type installation form and divide into SP, HP, DP and HR four kinds of network types and expanded the type of material section.

Mark example: HG/T 21618 wire mesh demister S1600-100 SP 304 indicates that 304 stainless steel of gratings and wire mesh, coat type, 1600 mm diameter, 100 mm height, SP screen demister grid.

SP type demister pad	DP type demister pad	HR/HP type demister pad

Type	Standard wire specification
SP	0.1 mm + 0.03 mm �� 0.4 mm
DP	0.1 mm + 0.02 mm �� 0.3 mm
HR	0.23 mm + 0.03 mm �� 0.4 mm.
HP	0.1 mm + 0.03 mm �� 0.4 mm

HG/T 21586-98 (drawer mesh demister device)

This standard is appropriate for the demister element, which is often needed to be replaced or cleaned, for example sulfuric acid drying tower and absorber device. The nominal diameter has 56 kinds ranging from DN 30 mm to DN 5000 mm.

Mark example: HG/T 21586.11-98 WME 1600-100 NS-80/Q235-A refers to the wire mesh using NS-80 carbon steel grill, 1600 mm in diameter, 100 mm in height drawer type demister pad.

Other non-standard wire mesh demister

Wavelike type, embedded type, external loading type, SWD1 type, square, rectangular and irregular and so on.

Mesh pad installation

There are two kinds of wire mesh demister pad, which are disk shaped demister pad and bar type demister pad.

According to different using condition, it can be divided into upload type and download type. When the opening is located in the above of the demister pad or when there is no opening but has flange, you should choose the upload demister pad.

When the opening is in the below of the demister pad, you should choose the download type demister pad.