Where Did the Question About the Diameter of the Concertina Come from?
The reason for the appearance of such a seemingly simple question was a number of factors - from the labeling of the concertina by the manufacturer, to doubts about its diameter in the prescribed form. Concertina, especially with a small number of clips, can look much smaller than indicated in its characteristics. Attempts to measure the diameter of the installed concertina also do not clarify this issue - when measuring the diameter of the same concertina, different values obtained, and all of them are less than those declared by the manufacturer. So what is the problem?
Coil Diameter and Installed Concertina Diameter
We, like most other concertina makers, list the coil diameter when it is an unstretched coil. During installation, the concertina stretches for a certain distance, and at the same time, the diameter of its turns decreases. This is a normal process and should be taken into account when planning the construction of barriers that use concertina. For each concertina model, we indicate the optimal stretching length, while reducing its diameter will be about 10%. If the optimum stretch length is exceeded, the effectiveness of the concertina will decrease and its diameter may change unpredictably due to deformations caused by the overstretch.
The Difficulty of Measuring the Diameter of the Concertina
Why is it difficult to measure the diameter of a concertina? In the case of a spiral barrier without clips, everything is simple - its coils in the installed form have an ideal shape, and when stretched, their diameter decreases in proportion to the stretch. The change in the diameter of the spiral barrier is not affected by the clips, so it is easy to measure. In the case of the concert, everything is more complicated. The presence of clips causes the diameter of the concertina to change in a non-linear manner when stretched. In addition, an odd number of clips fastening the coils of the concertina leads to the fact that the installed obstacles have the shape not of a cylinder, but of a polyhedron, at the vertices of which there are clips, and on the opposite side of the concertina there is an empty cell. It is quite difficult to measure the distance from the clip to the void in the cell, especially in a concertina with a small number of clips. For this reason, all attempts to measure it in the prescribed form lead to various incorrect results.
How to Find Out the Diameter of the Concertina?
Checking the characteristics of the concertina specified by the manufacturer is quite simple - you need to measure its parameters in the form of a coil. Trying to measure the parameters of the concertina, which has already been installed on the fence, is very difficult. You just need to trust a reliable supplier and take into account the reduction in the diameter of the installed concertina when planning fences using it.