Drain Camera

A Drain camera is an endoscope that is equipped in such a way that it is also suitable for inspecting pipelines. The particularly long semi-rigid camera hose can be easily pushed into extensive ducts or other cavities. For long distances, a camera trolley is often used, which not only makes it easier to move forward, but also protects the camera head. This makes it possible to detect the damaged areas, leaks and deposits in the pipelines without having to expose the sewers or dismantle sections of them. With the help of the drain camera, it can be determined non-destructively where defective connections, cracks, breaks or blockages in the pipeline are causing problems. In most cases, the images from the sewer camera can be used to decide immediately how to eliminate the problems and whether measures need to be taken to prevent them from recurring. The success of cleaning, flushing measures or repairs and the execution of new connections can also be checked and documented with the sewer camera.

Of course, the camera hoses of the drain camera are completely watertight due to the intended use and are also protected during immersion. Often the cameras are also specially protected against scratches and other damage by the protective cover. A nano-coating of this protection ensures that dirt and moisture bead off immediately so that the channel camera can take usable images. The control panel is also designed for outdoor use. In many models, the control unit can be fixed to the hose reel in such a way that no special separate shelf is needed and both are easy to operate and transport. The units are equipped with powerful rechargeable batteries that can be recharged with a mains adapter or a car charging adapter. However, with the wide range of devices available, there are significant differences in the features. To ensure that the selected drain camera meets the requirements for the intended applications, the most important criteria should be defined in advance.

Length and diameter of the camera hose
The first criterion when selecting the drain camera is the length of the camera hose. How long are the sections to be inspected in one go? Standard lengths available include 10 m, 20 m, 30 m, 40 m, 60 m and even 120 m. However, the longer the camera cable, the more difficult it is to guide the push cables in the narrow places and at junctions or changes of direction. For this reason, accessories for the long camera hoses to make it easier to guide the camera are almost always offered. These screwed-on accessories not only make pushing easier. Some also make it possible to navigate the vertical channels, and with all of them the sensitive camera is protected. Whether it is a guide ball, a centring brush or a guide carriage, the accessories are always matched to the diameter of the camera hose.

Once it has been determined which tube length is required for the drain camera, it should be checked which of the optional options for camera guidance is best suited for the ducts to be examined. Then an endoscope cable for which this guiding aid is available should be chosen. Some visual inspections can also be performed with a drain inspection camera without additional camera guidance. In these cases, however, while moving the drain camera, it should always be checked on the display that the camera head is not pressed against the obstacles with force. Not only the lens of the camera can be damaged, but also the signal cable if it is compressed and bent too much. The drain camera can be used for very different duct cross-sections. If the intended work cannot be done with a standard model, a model should be chosen for which camera hoses with different lengths and diameters are available. These endoscope cables can then be easily interchanged.

Features of the camera head
The image section of the actual camera at the head of the camera cable is determined by the optical features of the angle of view and depth of the field of view. While some versions have a predetermined depth of view of 20 to 100 centimeters, in the others it starts at one centimeter. The recognizability of the images is usually improved by additional lighting. In many camera heads, these LEDs are dimmable. In other versions of the channel camera, the image quality can be increased by means of the adjusted exposure times. Large drain cross-sections, connections and branches can be inspected in detail using a drain camera with a rotatable camera head. Such camera heads can be rotated horizontally up to 360 degrees and vertically up to 180 degrees. There is also a sewer camera with a self-levelling camera head for special purposes. With this type of camera, the images are always displayed horizontally, regardless of the position in which they were taken.

Display and control unit of a drain camera
The display and control units differ, among other things, in terms of display size and resolution. From the handheld unit with a 3.5-inch TFT display and 640 x 480 pixels to high-end units with a 10.1-inch LC display and 1,280 x 800 pixels, a variety of equipment is available. Images and videos can be stored on SD cards and later easily transferred to a computer for evaluation and documentation. The longer the camera hose, the longer the distances that can be examined in one go with the drain inspection camera. For this reason, the device models with long lengths offer higher storage volumes of the SD cards that can be used, so that they do not have to be changed during the drain inspection. For example, a drain inspection camera with a 60 or 120 meter camera hose can store data on SD cards with up to 256 GB storage volume. For direct display on larger screens, a sewer camera usually has an AV connection and sometimes also an HDMI interface. A USB port can be used to transfer the data to a PC or laptop. A microphone is often integrated into the control unit of the drain camera so that the videos of the damaged sites can be annotated directly during recording. These audio comments make it easier to assign the videos and shorten the time needed for post-processing.

Length measurement and position determination with the drain inspection camera
Especially when inspecting long stretches of the sewer, it is advantageous if the drain inspection camera has a length measuring device. There are versions of the device where the length of the hose that has already been unrolled is displayed on the cable drum of the drain inspection camera. This means that any faults or anomalies detected can be assigned to this length measurement and located easier. For necessary repairs, this meter count indicates the distance to the starting point of the measurement. For the buried or otherwise concealed pipelines where a more precise position determination is required, the sewer camera with a transmitter on the camera head and an additional receiver should be selected. This additional receiver enables the drain inspector to find the exact point of a detected damage on the inspected sewer from the outside. The locator detects the radio signals transmitted by the transmitter on the inspection camera head and thus determines the exact position and depth. This can reduce the amount of exposure required for repairs.