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Esfo Conveyor Belts GRZK Enrober Belt (general)
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Belt for straight conveyors Belt for curve conveyor Sprockets
GRZK enrober belts are used in many industries. The belts have a light weight single layer construction
and are positively driven by sprockets. The belts have an open structure (70 - 85 % open) and are
frequently used in cooling, baking, draying, heating, decorating, battering and packing machines for
light products.
GRZK enrober belts are made of stainless steel wire of spring wire. Wire diameters varies from 0,9
until 2,8 mm. Pitches from 4 mm until 19,05 mm, and belt widths from 10 mm until 3 metre. Esfo has
a big range of standard dimensions, but can make all the (non standard) dimensions too because of
the multi adjustable production machinery. Belts executed with single loop (most common) or double
looped edges for special occasions.
GRZK enrober belts can be made for straight conveyors and for curve conveyors.
GRZK enrober belts can be equipped with little cams, or with special formed internal wire to carry the
product on a special way. The very small ‘chains’ are used in spreader conveyors.
GRZK enrober belts are normally driven by toothed sprockets, made of (stainless) steel or plastic.
These sprockets are made to fit the belt and are adapted to the diameter you wish. The number of
teeth is free to choose and can be made for every new or existing conveyor. Esfo has for a number
of belts sprockets on stock.
GRZK enrober belts are often used in conveyors for the food industry for the production of:
-snacks -fish -pizzas -vegetables
-bread, pastry -meat -candy -(small) potatoes
-biscuits -chocolate -nuts and fruits
GRZK enrober belts are used on other industries to convey products like little parcels in packing and
plasticization machinery.
Esfo Conveyor Belts GRZK Enrober Belt (technical info)
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GRZK with single looped edges
GRZK wit double looped edges
GRZK-enrober belt is made from pre shaped wires with the same form, weaving together. The
drawings as showed above give the standard execution of a single looped edge belt (most common)
and a drawing of the double looped edge (only small pitches, and wire diameter from 0,9 until 1,2 mm)
belt for straight conveyors. The belt is determined by the pitch (P) de wire diameter (D), the number
of the spaces and the dimensions of these spaces (E and F). The looped edge (G) is determined by
the wire diameter. The width of the belt is free to choose.
The number of spaces is always odd, and is determined by the width of the belt. The strength of the
belt is given by the number of spaces. The space length is limited and normally between the 35 and
90 mm. The table below shows the preferable pitches (P) with the possible wire diameters (D1-D5)
and its average belt weights (M1-M5)
The bolt pitches and diameters are preferable.
All the pitch dimensions in between the preferable pitches are possible too.
Next table gives a view of the minimum and maximum sizes of the spaces (E,F),
belt width (B) and the looped edge(s) (G,H). The minimum and maximum sizes are
determined by the wire diameter (D).)
Note 1: The dimensions E and F are almost always the same. It is possible to vary in different
dimensions, or give the belt a certain pattern, using smaller and bigger openings.
Note 2: The Belt thickness is approx. 2,5 x the wire diameter.
Because GRZK-enrober belts are mainly used to convey little light products, the pitch of the belt mostly
will be determined by the product size, necessary transfer rollers and process conditions.
Next table gives an impression of the allowable tensile and velocity of the enrober belt.
The strength of an enrober belt is mainly determined by the diameter of the wire and the number of spaces.
The life-time of an enrober belt also will be determined by the product, the process and the number
and material of the support profiles.
Measuring:
The pitch (P) is very important. The wires have to fit exactly
into the holes of the sprockets.
In case of replacement, the pitch has to be measured exactly.
Normally you measure 10 pitches in the length of the belt
(from wire 1 until wire 11).
The measured dimension is only to be divided by 10 and gives
a dimension in 10th of mm.
Give the belt a little (no deformation) pre-tension while measuring,
and measure next to the knots, and not in the middle of a space,
to get the most accurate dimension.
Materials:
GRZK-enrober belts are made of first class material with a high tensile strength:
-Stainless Steel Aisi 302, Werkstoff 1.4310.
(normal corrosion resistant, normal purposes, food industry)
-Stainless Steel Aisi 316, Werkstoff 1.4401 or Aisi 316 Ti, Werkstoff 1.4571
(extra corrosion resistant, especially in case of aggressive chemicals, acids or chloride)
-Spring wire
(Steel, high tensile strength, little wire diameters)
Esfo Conveyor Belts GRZK Enrober Belt (Driving Components)
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Usually the GRZK-enrober belt is driven by one shaft of teethed sprockets. The other (reversing)
shafts are plane or have plane rollers. A properly set up support, (reversing) shafts and driving
shafts will keep the belt in a straight line.
The dimensions of the driving sprockets depend on the
preferred number of teeth, outside diameter and or shaft
bore specifications. The sprockets are tailor made and
have usually a width of 14 mm. Two driving sprockets are
mounted to drive the belt in every odd spacing.
The free space between the sprocket and the knots of the belt
is to be advised for 5 mm.
Sprockets are made from plastic (polyacetal, polyamide)
or stainless steel.
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It is possible to drive the belt too with sprockets filling
an entire spacing.
Further more the drive shaft can be executed as
a driving drum with the same width as the belt.
For special needs, please contact us, to make a
tailor made design.
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The table at the left shows an example of
diameters and number of teeth.
GRZK-enrober belt has a product side and a non product side. The product side is flat. The knots are
on the non product side. The product side has a small minimum turning radius (sprockets, take over
rollers, positive bending).
The turning radius of the non product side has a bigger turning radius (reverse or negative bending of
the belt)
The figure below gives three executions of take over rollers/shafts for positive bending of the enrober
belt.
Enrober Belt
Figure 1:
-A returning or non returning shaft
-Non returning shaft with turning
rollers
Figure 2:
Shaft with turning rollers
Figure 3:
Solid plastic edge
Table (right) gives the minimum positive bending diameter
(Dp) and negative bending diameter (Dn) related to the
pitch of the belt.
Note: These little take over diameters are not to be advised
for longconveyors and or bigger product loads. Using a
bigger diameter gives a better life time.
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Product side of GRZK is flat.
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The knots of the belt are at the non product side. |
Esfo Conveyor Belts GRZK Enrober Belts (Lay-out)
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Execution 1:
Driving shaft and idle rollers
Execution 2:
Two times mesh rollers, one negative
bending, one driving shaft.
Execution 3:
Like execution 2.
Execution 4:
Two times negative bending, one driving
shaft, two mesh rollers
Execution 5:
See execution 3, but with extra gravity
tension roller.
Esfo Conveyor Belts GRZK Enrober Belts (Support)
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The number of support of the GRZK enrober belt will be determined by on the process and the
product load. The position is normally between the knots of the belt. In case of a big load, every
spacing needs a support. In case of normal and light product load every 2nd or 3rd spacing a
support profile.
For proper running it is advised that at the support is always needed at the spaces at the left and
right side. Another possibility is to support the entire belt with a plastic sheet. The returning past
can be supported by rollers or by support profile. By the selection of support profiles, sprockets
and rollers, be aware not to tension the belt.
For processes up to 70-80 degrees C, it is common to use plastic support. For higher temperatures
the enrober belts are normally supported by Stainless Steel. (e.g. baking ovens).
Esfo Conveyor Belts GRZK Enrober Belt specials (cams, flights, chain)
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GRZK-enrober belt can be ececuted with
cams. Execution and patern can be choosen.
Cams to be used as a product support or
product guidance. Cams normally in light
enrober belts.
The cam types 1 until 3 are the most common.
For very delicat products cam type 2/3 can Nor
only executed upwards or downwards, but in the
Cam type 1 Cam type 2 Cam type 3 same level as the belt too.
It is possible to execute the belt with separate
flights
The enrober chain is very small.It has a pitch
of 7,2mm and a width of 9mm. It is used
in spreader conveyors.
Esfo Conveyor Belts GRZK Enrober Belt specials (curved belts)
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The GRZK-enrober belt can be executed as a curved
belt too. Normally for curves from 30 until 180 degrees.
The inside belt radius is fixed. The belt has a smaller
inside pitch and a bigger outside pitch. is small, the
pitch at the outside
Take over rollers have a minimum of 40 mm.
The execution of the GRZK belt is determined by its
conical construction and the belt is only in a range of
dimensions available (see below).
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For other dimensions please contact us.
Esfo Conveyor Belts GRZK Enrober Belt (assembly)
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I
Remove a wire out of the belt.
Cut the wire. Use the spaces which are not
driven by the sprockets.
II
Bring both belt ends together, and start with
the outside loops.
III + IV +V + VI
Hinge the parts of the belt with aid of common
tooling.
VII + VIII
Place the wire ends in the tubes and force the
tubes tight. Reshape the connection wire if
necessary.
Esfo Conveyor Belts GRZK Enrober Belt (Connection)
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I
Remove a wire from the belt.
Use this wire as a connection wire.
Bring the belt ends A and B together.
For wide belt, connect temporary the
outside loops together.
II
Start weaving the connection wire from
the middle towards the left side and
towards the right side.
III
Continue part II. Disconnect the temporary
connection at the outside belt. Connect the
spaces and end with the single or double
loop at the sides.
IV
Disconnect loop C.
For single looped belts see step VII
V
Connect the inside loop
VI
Connect the outside loop (B).
VII
Connect outside loop (C).
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