• What is a wedge wire screen
  • Types of Screens
  • Industrial Applications
  • Wedge wire Profile

What is a Wedge Wire Screen ?

It is a sieve made from looped wires formed into a deep wedge-shaped section. Individual wedge wires are built into " Panels " by threading cross rods of suitable diameter through the loops. The whole is then clamped and made secure usually by riveting or putting ring nuts over the cross rod ends or by welding.

The wedge wire screens can be supplied in various shapes and forms as per the requirements such as FLAT PANELS, CURVED SIEVE BENDS, CONICAL BASKETS, CYLINDERS, TROUGHS DISKS either in one one piece or in segments. For curved, cylindrical and conical screens in most cases the cross rods lie along the circumference and profile wires run parallel to the axis. Occasionally this arrangement is reversed.

ADVANTAGES : Wedge Wire Screens provide a unique combination of the most important features required for maximum screening efficiency.

A. Free Clearance
The wedge-shaped sections of the wire from aperatures that become progressively wider in a downward direction, thus ensuring rapid flow of material through them. Clogged and blinded aperatures are reduced to an absolute minium.

B. Lateral Strength
In our opinion no form of screening surface witl i apertures as fine as those of wedge wire screens, can compare with the mechanical strength and working efficiency of wedge wire.

C. Percentage Open Area
For a given aperature size, wedge wire screens have a much larger percentage of open area than conventinal sieves.

D. Wearing Life
Owing to a greater wearing area being provided by hat top surfaces, wedge wire screens retain their aperature for a longer duration than round wire screens.

Some other advantages of Looped type of wedge wire screens over other type of screens and also other type of wedge wires are

Self Supporting High Abrasition resistance Low pressure drop High resistance to Vibration

Looped Wedge Wire Screen construction is particularly recommended when high Vibration resistance and fine accurate aperture are needed.

FRAMING AND REINFORCEMENT :

Wedge wire easily lends itself to a variety of screen pannel Constructions. Many different side finishes are available.

some of which are given below :

1. Cross rods riveted at both ends.
2. Side angle.
3. Single side flat.
4. Spaced double side flats.
5. Side rubber with ferrules

The screens are reinforced with single reinforcing flat, double reinforcing flat and combination of single and double reinforcing flats welded to end flats.
However framings should be as per fitment design in the check. Customers are required to specify framing pattern with the order.

Special screens can be devloped for customised applications not covered by hte methods mentioned above.


WELDING :

A further method of strengthening a wedge wire screen panels, in addition to framing and reinforcements, against transverse bending is to put a run may be continuous along the whole length of the cross rod or skip or staggared welding may be employed.

SPACING LUGS :

In special cases involving side loading (Cross feed) on fine aperture wedge wire, specing lugs are introduced to give lateral support at points between the loops and shorten the unsupported span to maintain accuracy of the aperture.

Mounting Of Wedge Wire Panels On Vibrating Deck Frame :

While mounting of Wedge Wire Screens panles, utmost care should be taken that all screen panels are rigidly fixed on the deck frame. The cover rail of Flats used for bolting the panels on the deck frame must not be put directly on the panels surface. Rubber packing in between must be provided.

Sufficiant rigid fixing is necessary so as not to develop any secondary vibration (flexing) under operation as this will result in premature failure of screen panels. To ensure

the rigid fixing during opeartion periodical check of tightining bolts is recommended.

Wedge wire general data on apertures and sections :  
APERTURE
SECTION
NUMBER
APPROX OPEN AREA%
0.10 mm

20
23
28
32

5.5
5.0
3.6
3.1
0.125 mm
20
23
28
32
6.7
6.0
4.8
4.4
0.25 mm
20
23
28
32
12.5
11.1
9.2
8.2
0.375 mm
20
23
28
32
16.5
15.0
12.7
11.3
0.40 mm
20
23
28
32
20.7
18.8
16.1
14.4
0.75 mm
23
28
32
25.2
21.9
19.8
1.0 mm
23
28
32
48
30.9
27.2
24.7
17.5
1.25 mm
35
26.9
1.3 mm
33
41
28.4
22.1
1.50 mm
23
28
35
49
38.8
34.7
30.2
23.4
1.75 mm
28
35
37.0
32.6
2.0 mm
39
49
63
32.8
27.4
24.8
2.5 mm
42
49
36.0
32.1
3.0 mm
44
51
54
38.5
35.9
34.9
4.0 mm
51
54
42.0
41.0
OvIver 4.0 mm
Details on request

  CYLINDRICAL SCREEN

WEDGE WIRE PROFILE DIMENSIONS

SECTION
NUMBER
PROFILE
WIDTH
mm
PROFILE
DEPTH
mm
20
1.70
2.74
23
1.93
3.07
28
2.33
3.83
32
2.66
4.32
33
2.77
4.50
35
2.90
4.70
39
3.28
5.31
42
3.50
5.72
44
3.66
5.90
41
3.91
4.87
49
4.08
6.63
51
4.32
6.98
54
4.52
7.34

ROTARY SCREEN

MINI - WEDGE WIRE SCREENS:

Mini Wedge Wire is a development of standard Wedge Wire, complementing the micro fine range of aperture. It is virtually the same in constructional details, each individual panel is built from looped and pressed wires assembled on threaded rods. Mini Wedge Wire can be supplied with the following combination of aperture and cross rod.

APERTURE CROSS
ROD DIA
PITCH NO.OF LUGS
WITHIN
1 PITCH
0.05 mm (50 Micron) 5 dia 70/66 mm 2
0.75 mm (75 Micron) 5 dia 70/66 mm 2
0.10 mm (100 Micron) 5 dia 70/66 mm 2

 

APERTURE CROSS
ROD DIA
PITCH
0.05 mm (50 Micron) 3.2 dia 25.4 mm
0.75 mm (75 Micron) 3.2 dia 25.4 mm
0.10 mm (100 Micron) 3.2 dia 25.4 mm

 

APERTURE CROSS
ROD DIA
PITCH
0.05 mm (50 Micron) 4.80 dia  38.1 mm
0.75 mm (75 Micron) 4.80 dia  38.1 mm
0.10 mm (100 Micron) 4.80 dia  38.1 mm

 

HOW TO ORDER WEDGE WIRE SCREENS

While sending your enquiry or order for wedge wire screens, it is most important to give information in full detail. Not only does this ensure that the screens exactly correspond to the specifications laid down, but should there be an alternative make-up using perhaps a different profile, section size or method reinforcement, it can be put forward for consideration. The following information is essential :

Wedge Wire Details:
Aperture
Section Number
Profile
Metal

Screen Details: Number needed Overall length - parallel to wedge wires Overall width - parallel to cross rods Are cross rods to be secured by riveting, screwing or clamping? Is there any reason for wedge
wires to extend more than half a pitch beyond he end cross rods?

Side Frame Details:
Material
Dimensions of cross sections: 
Sketches - Show details of the frame and relative position of wedge wires. 
Sketches -
 Show location and size of bolt holes:, wires, bolt holes in notches side or rubber frame.


TYPES OF SCREENS

1. Flat Panels

Flat Panels are the most widely used type of Wedge Wire Screens mainly in the mineral processing both for stationery as well as vibratory decks. Flat panels manufactured by GUJARAT WEDGE WIRE SCREENS LIMITED are most dependable for effective sizing or classifying as they have accurate bar spacing from as low as 0. 0 1 mm to 4.5mm at interval of 0. 0 1 mm. Because of Looped construction they probably have the highest strength for any particular size and are self supporting and do not require support for long distances. The panels are either continuously or intermittently welded on the lower side of loop to provide complete rigidity to the panels thus becoming very effective in transmitting the vibrations without mechanical failures. The panels can be made with any type of fitment as per the requirement of the customers and for particular machines i.e. the side bar can be of Mild Steel or Stainless Steel square bar or of good quality square rubber, rubber strips, hook strips etc.

2. Curved Screens / Sieve Bends & Cylinders

In addition to flat panels, wedge wires can be readily made up into full cylinders and segments of cylinders. In most cases, the cross rods lie along the circumference and the profile wires lie parallel to the axis. Occasionally, this arrangement is reversed.

3. Centrifuge Baskets

Very high efficiency Baskets are made from Looped Wedge Wires in Conical shape, Cylindrical shape and in double Cylindrical shape i.e. Pusher type centrifuge. The wedge wire baskets have clear advantage of very high filtration efficiency, longer life and accurate aperture over any other Conventional screen baskets. Conical and Cylindrical baskets can be tailor made to suit the customer requirement and maximum efficiency.

4. Rotary Wedge Wire Screens

GUJARAT WEDGE WIRE SCREENS LIMITED has developed Rotary screens complete with side flanges and support/ drive drums of Stainless Steel/ Mild Steel mainly for Sugar and other Chemical plants to achieve very efficient filtration. Our rotary screens have very .high strength coupled with very high open area and rigid construction.

5. Run Down Screens

GUJARAT WEDGE WIRE SCREENS has developed run down screens (D.S.M. type) complete with box and curved wedge wire screens to suit particular requirements of the customer in Sugar, Paper and Pulp, Water treatment and Chemical industry

INDUSTRIAL APPLICATIONS
Wedge wires can be employed in almost all industrial processes which require very fine and uniformly accurate aperture, combining rapid discharge of material and high mechanical strength. Some of the specialized applications of these screens are given below:
Wedge wire screen used in industries for water, oil filtration equipments like

Filteration Equipments
Filtration Systems.
Filters.
Wedge Wire Screen.

1. Coal and Coke Washeries
Flat and curved wedge wire screens and Centrifuge Baskets with suitable re-inforcements are used for dewatering processes on stationary and moving frames, suction filters and centrifugal driers.

2. Ore Beneficiant Plants

In Iron and other Ore benificiant plants, wedge wire flat screens, Curved screens and Centrifuge baskets of fine and very fine aperture are used for efficient Dewatering and recovery of fines.

3. Sugar Mills.
Flat, curved and cylindrical wedge wire screens are used for Juice Filtration and Bagasse Separation drainage in tanks in conjunction with scraper conveyors as well as for draining crushed sugar cane supply in D.S.M. Screens.

4. Cement, Chemical and Fertilizer Plants.
Flat panels, Curved wedge wire screens, Cylinders and Centrifuge baskets with cylindrical type, conical type and pusher type have many and varied applications in these industries.

5. Cellulose, Wood and Straw Pulp and Board Industries
Wedge Wire cylinders, Flat panels and Centrifuge baskets are used for preliminary screening for knot catchers and for efficient fibre recovery Wedge wire screens ensure greater efficiency than the conventional perforated or machined slotted plates.


6. Sewage, Effluent and Water Treatment
Flat wedge wire decking in final settlement tanks provides tertiary treatment for the reduction of suspended solids. It is also the medium used in a technique for the consolidation of sludges where the rate of filtration is controlled at low operating pressures. Sewage, aluminium hydroxide, iron hydroxide and other industrial sludges are being successfully dewatered on wedge wire.

7. Malt & Food Grain Drying Floors & Solvent Extraction Plants
Wedge wires are also used for making up ventilation floors and has been found very suitable for malt kiln flooring, grain drying flooring and air curtains. Vertical type Solvent Extraction Plants also uses Wedge Wire Screens for high efficiency of extraction.

8. Salt Washery
Cylindrical and Conical type centrifuge baskets of fine aperture to suit any existing centrifuges having precise aperture, high mechanical strength and corrosion resistance are extraordinarily being used in modern salt washeries. Curved screens are also being used. The usual aperture ranges from 0.075mn to 0.2mm.

WEDGE WIRE PROFILE :

Wedge Wires can be supplied in the following profiles

1. FLAT TOP:
The most commonly used Profile giving best screening efficiency over the whole range in most applications. It is excellent in dewatering of slurry, and is extensively used in Coal Washeries. We denote FLAT TOP as profile which is equivalent to commonly named "b" profile.

2. SQUARE TOP:
Suitable for the larger aperature screens used with highly abrasive materials. The parallel section allows a considerable wear on top surface before the abrasion affects the widening of aperture. However, for fine slit the clewatering efficiency is lower than the flat top because of greater tendency to blind the aperature. Our Square top profile are equivalent to commonly named "c" profile.

3. DOUBLE ANGLED PROFILE:
This special profile has two angles, along its vertical depth, which impart both lateral and vertical strength to the profile. It is suitable for finer aperature Screens. Its free clearance efficiency is slightly lower compared to FLAT TOP profile but has higher life against wearing. This double angled profile is equivalent to commonly named "a" profile.

4. CONICAL TOP:
Designed particularly for fine mesh screens for dewatering of slurries, the sloping top directs any water or other fluid present towards the slit apertures. Much of the abrasion due to the passage of material over the screen is borne by the conical top which can wear down without affecting the accuracy of the screen. It has slightly more tendency to "blind" than with the flat top.

 CROSS RODS DIAMETER AND PITCH :

The Standard sizes of Cross rods and pitch provided are:

  1.  7.6mm diameter cross rod at 70mm pitch.
  2. 12mm diameter cross rod at 70mm pitch.
  3. 7.6mm diameter cross rod at 66mm pitch.
  4. 12mm diameter cross rods at 66mm pitch.
  5. 5mm diameter cross rod at 70mm pitch with two spacing lugs on the profile wire.
  6. 5 mm diameter cross rod at 66mm pitch with two spacing lugs on the profile wire.

    Out of the above Sr. No. I & 2 are most common and widely accepted combination and Sr. No. 3, 4 , 5 & 6 are for special applications.