Tube cleaning

The method of pipe cleaning refers to the activity or the apparatus for cleaning and maintenance of pipelines. By the pumped medium in the tubes can cause deposits and finally the partial blockage. In plant and industry specific requirements for pipelines with respect to surface roughness or heat transfer are provided. In the food processing and pharmaceutical industries as well as in medical technology, the requirements are sterility and freedom from foreign matter, for example, after installation of the pipe or after a product change. It may also be due to deposits and corrosion will cause a failure of the pipelines.

Depending on the application, the pumped medium and pipe material has the following methods for pipe cleaning:

Lost tubes are tubes which have to be replaced after a single use. This type is in the true sense is not a true pipe cleaning and is widely used in the medical field, such as cannulae of syringes, infusion needles or medical devices such as artificial kidneys in dialysis. The reasons are first in the risk of infection, but also to a complex treatment that is related to the cost of a pipe cleaning especially in low- mass products in proportion. This technique is applied in accordance only with tubes with extremely small diameter up to 20 mm. For the same reasons, we find this approach to some extent in the food processing and pharmaceutical process technology, the diameter may be larger than 20 mm here.

Irrigation

The simplest method is a pipe cleaning pipe flushing. This often Spülauslässe or used in the drinking water system hydrants. Simply by increasing the flow rate most loose deposits are held. Nowadays in the field of drinking water, various rinsing such as:

• Flush
• Air-water flushing
• Air-water pulse lavage
• Suction flushing
• Solid flush

Employed.

Chemical tube cleaning

Under the chemical pipe cleaning refers to the use of cleaning fluids or chemicals to remove the deposits. A typical example is the descaling a coffee maker Here, the scale removed by citric or acetic acid. Depending on the application and material of the pipe may be either special cleaning fluids, and a multi-stage treatment:

• Chemical activation
• Cleaning

Make it necessary. This type of cleaning requires in any case a closure of each facility and also leads to downtime, which are often not desirable. For a continuous production operation, it is then necessary to install these systems several times ( redundant). Another disadvantage is that a large industrial area (reactor, heat exchanger, condenser, etc.) as the generation of large amounts of cleaning fluids, which can lead to disposal difficulties. Another problem arises in the food industry due to the possible toxicity of cleaning fluids. Here only strict adherence to the Spülvorschriften and an accurate residual volume control can remedy the situation. This requires elaborate detection methods. Overall, the process of chemical pipe cleaning for any diameter can be used, however, practical limits of use to the volume of a pipeline arise.

Mechanical tube cleaning

In the mechanical tube cleaning systems there is a cleaning member which is moved through the tube to remove deposits on the pipe wall. In the simplest case, it is an appropriate brush, which is by rod or a flexible spring in the tube back and forth. In large-scale and industrial field, but several different techniques have been developed.

Off-line

The offline methods are distinguished by the fact that for the pipe cleaning, the installation to be cleaned must be taken out of service to perform the cleaning or the body on and the cleaning process. In these methods, you still have to still distinguish between passive and active cleaning bodies.

• The passive cleaning body can both brushes, or special constructions such as pigs (but see also below) be, which are moved by means of compressed air, water or other delivery medium through the tubes. Usually cleaning is carried out by the interference of the cleaning element relative to the pipe inside diameter. The types range from brushes with bristles made of plastic or steel scrapers for smaller pipe diameters to complex designs with built-in spray nozzles in pipelines. This method in the nominal size range of about 5 mm is applied to several meters. In the same area, the cleaning clogged drain pipes domestic sewers with a rotating flexible shaft falls.

• The active cleaning body, also called pipe manipulators, are more or less remote-controlled robots that move, both cable for power supply and communication as herziehend and hose assemblies for the cleaning fluid behind through the tubes and meet the cleaning task. In this case, measuring instruments or cameras are carried over in order to monitor the function. To date, such devices still require a minimum diameter of 300 mm, at a further reduction but worked. As maximum diameter meaningful for these devices can be about 2 m to be specified because this diameter from an inspection of the pipeline is certainly more cost effective. In this diameter range can be a use of robots imagine only harmful chemicals.

Online procedure

In the on -line process, the cleaning body moves with the fluid through the pipes and cleans them with his oversized relative to the pipe inside diameter. This cleaning bodies are in the diameter range up to about 50 mm sponge rubber balls, in larger nominal areas to oil pipelines newts. Sponge rubber balls are mainly used for cooling water such as lake, river or cooling tower water. Although adapted cleaning bodies are quite possible in the chemical or pharmaceutical industry; However, here the fluids flows are so low that most offline methods are used. Since the cleaning body must not remain in the medium, they must be separated again after the pipe run. This is done with sponge rubber balls through special screening devices in the Newts one discharge (so-called " pig - trap" ) is installed. The sponge rubber balls are then introduced by a corresponding ball return in Taprogge process again before the installation to be cleaned, the pig is usually removed by hand and fed back into another introduction. While the sponge rubber balls thus ensure continuous cleaning, pigging system is discontinuous.

Thermal pipe cleaning

In the thermal tube cleaning the surface is dried by heating, whereby he falls because of its brittleness and is transported either by the pumped liquid or washing liquid. When heating can be, depending on the required temperature to act pipe heating or an induction heater. In this method is an off -line process. Occasionally, the application takes place also for the sterilization of the pipeline in the pharmaceutical or food industries. A diameter range can be here do not specify, since the use of this method for certain processes is possible and the technical limit of the heating is given only by the materials and the amount of heat required.

Special shapes

Special forms of pipe cleaning are all those processes which are partly only in the experimental stage and are not covered by the methods previously mentioned, such as:

• Induction of pressure surges, so that the lining caused by replacing the short-term material strain. In groundwater wells, the impurities are dissolved and then as long as water pumped out until it is clear again occasionally with the help of detonating cords;
• Use of vibration, partly in order to make the pipes by vibration exciter, partly by means of piezoelectric crystals in the medium, by reducing the surface tension of the fluid is pumped to the cleaning medium;
• Magnetic fields to prevent pipe scaling ( efficacy is strongly challenged );
• Nanotechnical treatment of pipe surfaces to avoid deposits.