Valente - Anti-Hail Net

Product code : VAL/CAREN

The antihail net, as well as the shading net, is the most important element of the protection system, therefore it must be made using high quality materials and realised with the best technique in order to obtain a very light but resistant and durable sheet.

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Therefore, the quality of the wire and of the raw materials used are very important, as well as weaving technique:

The quality of the wire and raw materials

Plastic monofilament is used to weave the antihail net. This material is made by extrusion, melting and passing high density polyethylene (HDPE) through perforated grills (extruders). The wire is thermo-stabilised, or rather it is heated in order to reduce all retractions that plastic materials exposed to heat sources have (even moderate). Different sized diameter wires can be extruded and, consequently, it is possible to obtain materials with different resistance. The wire used by Valente for weaving the antihail nets has only a 0.31mm diameter: this diameter guarantees a resistance of at least 3 kg per wire. This means that Valente antihail net is capable of withstanding very consistent hails.

Weaving technique

Valente antihail net is made using monofilament with a special technique called frame weaving; the weave obtained with this type of processing is 2.8 x 8mm rectangular shape and can not be deformed, that is to say that the size is not altered when the net is subjected to the weight of hail stones. Frame weaving, also known as rectilinear weaving, consists of crossing a system of lines placed according to the length of the fabric (warp threads), with a system of lines placed according to the width (weft threads).

The weft thread is wrapped around a spool that is inserted inside a shuttle (or shell), whilst the warp threads are fitted on a beam from which they are withdrawn and spread across the processing surface and passed in the frame weaves. The weaves are gathered in groups on two or more harnesses that are lifted and lowered in an alternating manner, taking some warp threads downwards and some upwards, depending on the pre-established plan (weave).

The shuttle is launched between the lowered and lifted warp threads, and deposits the weft thread, forming the crossed structure of the fabric. At each inversion of the position of the harnesses, the inserted warp thread is aligned next to the previous one using a comb. The number of warp threads determines the width of the fabric.

The weaving of Valente nets is “leno weaving”, or rather, the fabric has two warps: one straight and one sinuous that alternates its position from right to left of the straight line at each weft. Valente antihail nets can be white, grey or black. Transparent kristall monofilament is used to make white nets. To manufacture black nets, black monofilament is used, that is obtained by using special stabilising additives, starting from transparent polyethylene. In particular, black Valente single-wires are made using black carbon: this additive has optimum features that are stabilisers and is protection from UV light, a feature that preserves the plastic material from premature wear. Finally, the grey net is made by weaving white warp threads with black weft threads.

The antihail net has strong mechanical resistance, long durability and 15% shadowing effect. The white kristall net has a strong mechanical resistance, a reduced shadow (only 5%), but has a lower durability than the black net due to wear caused by UV light. This is where the grey net combines the positive features of the first nets: low shadowing effect feature of the white net, and optimal durability thanks to the weft threads (less susceptible to wear) in black polyethylene (HDPE).

Generally, there is no definite and agreeable data regarding the influence that the net, regardless of colour, has on the effect on the production of fruit systems. The only indication recognised unanimously by all users is the maturation delay (estimated to be around 5-7 days) that occurs with products that are covered with the black net.

The following indications are useful by choosing the colour of the net:

  • Black net: for all types of fruit
  • Kristall net: for fruit that has particular difficulties for colouring (old clones still in production or in poorly lighted geographic zones)
  • Grey net: for all types of fruit

Valente antihail net is certified and is guaranteed over the time. The documentation is given when purchasing the product.

NET WIDTH
H
LISTING TYPE BLACK NET GREY NET WHITE NET
H > = 3,0 m LATERAL BLACK, 15cm BLACK, 15cm BLACK, 15cm
CENTRAL BLACK, 12cm BLACK, 12cm BLACK, 12cm
2,00 m <= H < 3.00 m LATERAL BLACK, 6cm BLACK, 6cm BLACK, 6cm
CENTRAL BLACK, 12cm BLACK, 12cm BLACK, 12cm
1,00 m <= H < 2,00 m LATERAL BLACK, 6cm BLACK, 6cm BLACK, 6cm
CENTRAL ABSENT ABSENT ABSENT
H < 1,00 m LATERAL BLACK, 4cm BLACK, 4cm BLACK, 4cm
CENTRAL ABSENT ABSENT ABSENT
PHYSICAL CHARACTERISTICS
Black Net Grey Net Kristall Net
Polymer HDPE 100% HDPE 100% HDPE 100%
Weave shape Rectangular Rectangular Rectangular
Weave dimensions 2.8x8,mm 2.8x8,mm 2.8x8,mm
Packaging Polythene film Polythene film Polythene film
Colour


Weaving
Black


Leno weaving
Wrap: Kristall
Weft: Black
Leno weaving
Kristall


Leno weaving
DIMENSIONAL CHARACTERISTICS
Unit Of Measure Black Net Grey Net Kristall Net
Warp threads Threads nr / cm 2.16 2.16 2.16
Weft threads Threads nr / cm 3.2 3.2 3.2
Thread diameter mm 0,31 0,31 0,31
Title dr / den 650 +/- 5% 650 +/- 5% 650 +/- 5%
Unit weight +/-5% (according to UNIPLAST Standards) g/m2 48 +/- 5% 48 +/- 5% 48 +/- 5%
MECHANICAL CHARACTERISTICS
Unit Of Measure Black Single Thread Kristall Single Thread
Color stability to light Blue scale 8 7-8
(1=low , 8=excellent)
Resistance to U.V. Kly Round 750 Kly Round 500-550 Kly
Breaking elongation % 40% roughly 40% roughly
Breaking resistance gr/den 5 roughly 5 roughly
Shortening in water at 100 °C % 3,5% – 4% ca. 3,5% – 4% ca.