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Esfo Conveyor Belts RA Radius Belt (general)
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Example of a standard RA radius belt with a link at both sides, and if needed equipped with reinforcing bars.
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Example of a RA radius belt with a extra link in the middle to fit a smaller turning radius.
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The RA radius belt is a highly usable conveyor belt. The belt has been designed for a great many
applications, constructions and process conditions. The belt is eminently suitable for cooling or
freezing products such as snacks, bread, pastry, vegetables, potatoes, fish and meat, as well as
for blanching vegetables or proofing dough. The belt is used in radius systems, spiral towers as
well as in curved and straight conveyors.
The RA radius belt is constructed of cross rods with chain links on both sides and, in most cases,
is provided with balanced weaved spiral mesh for product support. The thickness of the spiral wire
and the spiral pitch can be chosen at will and allow the belt to give optimal product support. The belt
can also be provided with reinforcing links, extra plate links for product conduction, or with flights
The belt can be made in every width between 350 and 1,500 millimetres. Belts with widths smaller
than 350 mm, or greater than 1,500 millimetres and belts with unilateral spiral wire are made on
demand.
The Standard RA radius belt has many different versions to optimise your choice and is available in:
- 2 different pitches: 19,05 mm (3/4”) and 27,4 mm (1”)
- with or without spirals
- 3 different strengths: -normal (2 mm) chain link type: RA - NB
-heavy duty (3 mm) chain link type: RA -VB
-heavy duty chain link with double
reinforcing plate links type: RA –VP
- different ratios between the belt width and the rotating radius:
rotating radius = 1,7 x belt width or rotating radius = 2,2 x belt width
The Full Decreased RA radius belt is a belt with links at the outside and a link in the middle and is
available in.
- 1 different pitches: 19,05 mm (3/4”)
- with or without spirals
- 1 strength: -combined (2 and 3 mm) chain links type: RA - FD
- ratio between the belt width and the rotating radius:
inner radius = 1,1 x belt
Door de middenbeugel uit het midden te zetten kan de binnenradius binnen grenzen aangepast worden.
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The exact dimensions of the chain links and cross rods of the RA radius belt combined with the
computercontrolled welding robot and butting robot result in a belt with great dimensional stability
and with stable straight and curved radius characteristics under nearly all circumstances.
Two cold butted heads are fitted at either end of each cross rod. The absence of too much heat
during the fabrication ensures that the cross rod stays straight and that the structure of the outer
parts of the cross rods does not change. In this way, the cold butted heads always have the same
dimensions and are extremely smooth. The welds which connect the chain links to the cross rods
are welded with a minimum of heat and are very tough, due to the chosen welding process. All this
results in a durable belt of excellent quality.
The RA radius belt can be used at transport speeds of less than 1 metre per minute to about 20
metres per minute, which are considered normal speeds. In case of radius belts, the speed is
measured at the outside of the belt. Speeds above 20 metres per minute are considered to be
high speeds and can affect the life of the belt. The construction of the conveyor system and the
process conditions are also important considerations.
RA radius belts are used in production processes with temperatures of -196ºC to +275ºC.
The RA radius belt needs minimal maintenance and can have a working life of many years, if used
well. The belt is standard made of stainless steel AISI 304 but can also be made of AISI 316.
RA radius belts are used in, for example:
-Spiral and straight cooling systems - -Special cryogenic freezing systems
-Spiral proofing towers -Drying installations
-Product lifting conveyors -Baking systems
-Spiral and straight freezing systems - Pasteurising systems
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RA-NB Belt with standard links (11 x 2 mm)
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RA-VP Belt with heavy duty links (11 x 3 mm) and
reinforcing bars (11 x 2 mm) |
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Separate side plates for RA Radius Belt
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RA-FD Belt with link in the middle
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As shown below the RA radius belt can be executed e.g. with flights or special cross rods.
The belt is to use as a support belt for plastic or metal filtration belts too.
Esfo Conveyor Belts RA Radius Belt (technical info)
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RA-NB RA-VB RA-VP
d : Preferred diameter spiral wire: 1 - 1,2 -1,4 - 1,5 or 1,6 mm
19 - 18 - 17 or 16 Gauge
s : Each pitch of the spiral mesh between 3,2 and 12,7 can be selected.
Preferred spiral wire pitch: 3,2 – 4 – 5 – 6 – 6,35 – 7 – 8 or 12,7 mm
96 - 72 – 60 – 50 – 48 – 42 – 36 or 24 spirals windings / foot
BW : Belt width (maximum width of the belt)
Each width (metrical or inch) between 300 and 1500 mm (12 and 60 inch) can be
selected standard. Belts with larger or smaller widths are available on demand
R : R = q x BW (Nominal radius around which the belt can be rotated
Examples of a type specification:
Type of - Type of - Pitch - Pitch / Diam. - Diam.
Belt chain link spirals Cross rod Spir. Wire Cross rod
s - p / d - c
example 1 : RA - NB - 8 - 19,05 / 1,6 – 5
example 2 : RA - VB - 6,4 - 27,4 / 1,4 – 5
d : Preferred diameter spiral wire: 1 - 1,2 -1,4 - 1,5 or 1,6 mm
19 – 18 - 17 - or 16 Gauge
s : Each pitch of the spiral mesh between 3,2 and 12,7 can be selected.
Preferred spiral wire pitch: 3,2 – 4 – 5 – 6 – 6,35 – 7 – 8 or 12,7 mm
96 - 72 – 60 – 50 – 48 – 42 – 36 or 24 spiral windings / foot
BW : Belt width (outside/overall)
Belts widths are available on demand
R : R = q x BW = 1.1 x BW (Nominal radius around which the belt can be rotated).
Nominal radius around which the belt can be rotated. The chain link in the
middle is positioned exactly in the centre of the belt.
SPECIAL
Within certain limits, the rotating radius R can be adapted to specific requirements by positioning
the chain link in the middle off-centre of the belt.
EXAMPLE
Esfo Conveyor Belts RA Radius Belt (Driving and support)
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A RA radius belt in a straight conveyor system is positively driven. Toothed sprockets prevent the belt
from slipping. Between the sprockets a plain roller every 150-200 mm is to be advised. Consequently,
there is no need to have the belt set up with a certain tension. In normal use, a reverse shaft adjustable
in the belt’s running direction is enough to handle a possible elongation of the belt in the course of time.
The driving gear must be positioned in such a way that the loaded part, usually the upper part, is pulled
off the belt. A pushing driving gear must be avoided. Supporting the upper part usually is effected by
wearing profiles attached lengthways underneath the belt. Subject to the production process, synthetic
materials such as PA, PE, HMPE, is advisable to fit the supporting profiles underneath the belt. The
support profiles are placed at distances of about 200 to 400 mm, depending on the belt’s load, belt
weight and production process.
A RA radius belt in a curve conveyor system has to be supported and driven the same as in straight
conveyors, with this difference that the RA-FD belt with the link in the middle has the driving sprockets
positioned in the inside link and the middle link. The turning radius of the RA radius belt can be 1.1,
1.7 or 2.2 x the belt width. The infeed and outfeed lenght of the curve conveyor has to be straight and
ca. 1,5 x belt width. To give the belt some clearance, it is to be advised to give the belt at the outside
a space of ca. 50 mm towards the frame work.
A RA radius belt in a spiral conveyor is the most common. A spiral conveyor is more or less a special
curve conveyor with a take-up drive in the straight part and a driven inner drum driving the belt on friction.
The take-up drive gives the belt a controlled (low) tension. Because he cylindrical drum drives the belt on
friction it will run a little faster as the belt. Because a spiral conveyor normally has a lot of running metres,
a special section has to be installed to effect elongation of the belt (due to different temperatures and
product load).
Esfo Conveyor Belts RA Radius Belt (Plastic wear Strips)
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The UP-S and UP-EL profiles are normally available on bars of 3 mtr or 6 mtr and on rolls
The UP-HD profiles are normally available on bars of 3 or 6 mtr.
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