Plastic pipes are usually transported in cut-to-size blanks or round coils twisted into rings. In the second case, in order to bring them to a normal (straightened) form, they will need to be pulled out of the twist, deforming the packed material. With a sharp straightening at normal temperatures, they are often damaged in the area of \u200b\u200bthe fold. Therefore, it is important to figure out how to straighten a HDPE pipe without disturbing the structure of the material.
Such attractive properties of polyethylene products as their strength and elasticity appear only at normal temperatures. When it rises to about +80 degrees, the polymer becomes soft and viscous, so that the pipe blanks can be freely bent.
Note! This possibility is based on the production technology of HDPE pipes, in the manufacture of which the granules of the source material are melted at a temperature of approximately +130 degrees.
It follows from this that it is permissible to straighten pipes of the HDPE class (without destroying the base structure) when they are heated to slightly lower temperatures. At the same time, it is important to understand that its further increase can lead to irreversible consequences (to the complete destruction of molecular bonds).
The proposed methods for straightening HDPE blanks are based on the properties described above and allow avoiding undesirable consequences.
Bending (straightening) methods
There are several ways to straighten coiled tubular products. Some of them are extremely simple, but only valid in certain climatic conditions. To implement other options, tools and materials are needed to ensure their gradual straightening. In the list below, these methods are listed in order of increasing complexity:
- Heating pipes from a coil under the sun in hot weather (up to 30 degrees), when the rings soften so much that they can be unwound manually and without prior preparation.
- Application for their softening and straightening of a building hair dryer.
- Heating products with hot water, due to which their structure acquires plasticity and can be deformed.
- The use of a special molding device in the form of a stand with guide rubber rollers that allow you to level the hood from the bay.
Let’s consider each of these methods in more detail.
Straightening under heat
The first of these techniques is limited to ideal weather conditions and is used very rarely. When using it, you should be very careful and pull the pipe without undue haste, so as not to damage the bends.
In the case when a building hair dryer is used for this purpose, you should also work with it carefully, trying not to exceed the maximum allowable jet temperature (80 degrees). When heating with a hair dryer, keep it at some distance from the bay and slowly move it along the fold.
To heat HDPE products with hot water, you must first prepare boiling water, and then pour it into the internal cavities of the bay. When pouring, it will cool down to about 70-80 degrees and will normally warm up the folds.
Use of bench fixtures
It is also possible to straighten the HDPE pipe by means of mechanisms specially made for this purpose.
Note! This method of arranging their pipeline is resorted to with a significant length of pipes rolled into a bay and a small bend diameter.
The rotating rollers on it allow, when the workpieces are heated, to gently smooth out sharp bends in short sections. For ease of use, the device is placed on a trolley with rubberized wheels.
At home, without having either a hair dryer or boiling water at hand, pipes made under low pressure can be straightened by placing a heated bulk substance in them.
To implement this method, you will need to do the following operations:
- First, a sand or salt mixture of the desired condition is prepared.
- Then it is poured into a rag bag and placed in an oven with adjustable air temperature (it should not exceed 100 degrees).
- After heating, the mixture is poured into the bend of the pipe billet and left there for a while, after which you can begin to straighten it.
Additional Information! In the country, instead of the oven, you can take any suitable baking sheet used for cooking over an open fire.
To fill the hot mixture, it is recommended to use a special ceramic scoop with a metal funnel, which ensures the convenience of all operations.
In conclusion, we note that when choosing a suitable method for aligning HDPE pipes, preference is given to the option in which the impact on the structure of the material is minimal. This approach is very important for work, since these products will have a long operation as part of a self-assembled pipeline.