Endoscopic fiber catheter and its applications

An endoscope is an optical device that is used to study hard-to-reach cavities of mechanisms, machines, and equipment. In its simplest form, it is a long flexible or rigid fiber bundle with a lens, optical system, illumination, and eyepiece. In the case when the optical fiber is used for image transmission, such an endoscope is called a fiber optic one, fiberscope or endoscopic fiber catheter.

Light is used to transmit electronic signals over long distances. A single fiber bundle with a thickness of human hair can transmit all the signals necessary for the operation of televisions, telephones, and computers at home or in an institution. Such fibers, also called optical fibers, are usually made of glass or plastic.

The main element of a fiber optic cable or simply optical cable is an optical fiber waveguide. A fiber waveguide, or optical fiber, is an optical waveguide designed for the directional transmission of optical radiation, made in the form of a thin glass bundle of a cylindrical shape with a circular cross-section.

The optical fiber consists of a light-transmitting core, one or several layers of protective-reflective coatings, which prevent the diffusion of light. The fibers are collected in a cable, which can contain from 72 to 144 fibers.

Cables based on fiber optic technology are used in medical equipment and instruments. Standard technology includes the opportunity of inserting a special tool with flexible optical fibers, which can transmit a signal to an external camera inside the organs of the human body. Fiber optics is used in medicine as lighting material. Devices equipped with fiber modules allow painlessly highlighting the cavity of the stomach, nasopharynx, etc.

Modern endoscopic fiber catheters have a fairly complex scheme, which includes the following elements:

  • fiber optic probe with stainless steel coating and tungsten covering;  
  • fiber optic light guide to provide illumination and light transmission from the source to the distal end;
  • lens, interchangeable optics;
  • eyepiece;
  • body frame.

The design may vary depending on the purpose of use. So, for those cases when it is necessary to use ultraviolet illumination, the optical fiber with quartz fibers are used. The endoscopic fiber catheter must be absolutely dust-proof and waterproof, as well as resistant to aggressive environments, oils, gasoline, etc. The camera can be connected to the eyepiece through a special adapter for recording and documenting, as well as a display.

Endoscopic fiber catheters have a very wide range of applications. Due to the design features and the principle of operation, devices with a fiber optic probe diameter of up to two millimeters are produced, which allows quality control of internal surfaces and hidden cavities of almost any objects to which access by other means is practically impossible: turbines, aircraft wings, heat exchangers, pipelines and pipes of small diameter, etc.

Endoscopic fiber catheters, like their gradient, lens counterparts, are also commonly divided into two very broad categories. The first includes flexible endoscopes (the manipulator of such optical fiber devices can bend at any angle). The second includes devices of rigid type (the manipulator is straight and inflexible). It is flexible endoscopic fiber catheters that are used more actively and are in high demand for obvious reasons. And that’s all, even despite the higher price of such equipment.

A rigid endoscope (fiber optic bundle) consists of visual and lighting systems. The visual system consists of a lens, rod or gradient optics, which is enclosed in an internal metal tube. The lighting system consists of an optical fiber that is located between two metal tubes: external and internal.

Rigid endoscopic systems are characterized by four main parameters: the diameter and the length of the working parts, the angle of the observational direction and the angle of the view field. The main advantage of rigid endoscopes is their high resolution – up to 2S lines per millimeter.

Direct access to the object is not always possible or the object itself has complex geometry, for example, gas turbines, electric engines, turbogenerators, boilers, heat exchangers, water pipes, sewers, industrial communications. In this case, flexible endoscopic fiber catheters are used for visual inspection.

The visual system and the light transmission system in flexible endoscopes consist of fiber optics mounted inside a flexible fiber bundle with a controllable distal end.

Flexible endoscopic fiber catheters have a controlled distal end that bends in one or two planes. As a rule, this is determined by the diameter of the working part. The main disadvantage of flexible optical fiber endoscopes compared to rigid ones is lower resolution. It is necessary to pay attention to two main parameters when choosing flexible endoscopic fiber catheters: diameter and length of the working part. 

However, choosing a fiber optic endoscope, you will need to pay attention not only to the flexibility or rigidity of its manipulator but also to whether the case of such a product is waterproof. Resolution is also important. By the way, it is the resolution that is a very important indicator, and therefore it’s worthwhile to research this parameter in a little more detail. By simple and understandable words, the higher the resolution is, the better the quality of the image produced by the endoscopic fiber catheter is considered to be, herewith, such a fiber optic device will be more useful to your needs and the needs of your enterprise.

The main purpose of optical fiber endoscopes is a quick and high-quality visual examination of hard-to-reach cavities of machines and mechanisms without disassembling them. The most illustrative examples by industry are shown below.

  • Power industry – endoscopic fiber catheters monitor the state of heat engineering, electrical and other types of power plant equipment. For example, they are used to monitor the condition of the intra-cooling channels, the windings of electric generators and transformers, the inner walls of the pipes.
  • Water supply and sewage – optical fiber endoscopes detect damages, corrosion, blockages, cracks and foreign objects in pipes and tanks, they monitor the flowing part of pumping systems.
  • Metallurgical industry – fiber catheters are applied for the maintenance of production facilities, for example, inspection of furnace assemblies, as well as for quality control of forming.
  • Aviation and space industry – fiber optic sensing systems monitor the state of power elements of hull structures, tank walls, gas turbine blades and compressors, shells, sprayers, nozzles of combustion chambers, as well as they participate in the development and production of rocket engines and pneumatic hydraulic systems.
  • Mechanical engineering – endoscopic fiber catheters control the quality of manufacturing and check the technical condition of various components and parts of machines, for example, mold cavities, mechanical transmission parts, bearings, pipelines, soldered and welded structures cavities.
  • Security services, customs – fiber catheters are used for the quick search for explosive devices, drugs, weapons, smuggling, for inspecting the contents of opaque containers without opening them, and for a number of other special purposes.
  • Architecture and construction – fiber optic bundles check the state of power elements of ceilings, internal cavities, reinforcement and waterproofing of walls, condition of pipelines, as well as architectural modeling.
  • Gas pumping stations – fiber sensing systems monitor the condition of the blades, combustion chambers, fuel system and other components of gas pumping units, they check for erosion, corrosion, deposits and fatigue cracks in taps, valves, pipelines, separators, and other systems.
  • Chemical and petrochemical industry – optical fiber catheters perform systematic and emergency inspections of pipelines, pressure vessels, heat exchangers, pneumatic and hydraulic units and other devices.
  • Automotive industry – they control the quality of manufacture and assembly of engines, for example, the quality of cleaning forming from rods, control hydropneumatic systems, the quality of welding and painting. In operation – sensing systems for monitoring the condition of valves, cylinder liners, gear, corrosion of body parts.
  • Rail and sea transport – fiber optic catheters for inspection of diesel and electric engines, generators, transformers, and other units and assemblies.
  • Electronic industry – fiber bundles control and ensure the quality of production and assembly of electronic devices.
  • Science and education – the systems are employed for observing animals and insects, studying the root system of plants, etc. They include archaeological and exploratory work, an inspection of the internal cavities of statues and monuments.
  • Medicine

The benefits of optical fibers in medical fiberscopes

Modern endoscopic sensing systems (flexible endoscopes, fiberscopes) use fiber optics. Almost all organs became available for inspection by endoscopic fiber probes, the illumination of the organs under investigation increased, conditions for photographing and video recording (endophotography and endocinematography) appeared, and it became possible to record images on video (on external systems). Currently, endoscopic fiber techniques are used for both the diagnosis and treatment of various diseases.

If you would like to obtain an optical fiber product, you should choose the Optromix company. Optromix is a provider of top quality special fibers and broad spectra fiber optic solutions. The company delivers the best quality special fibers and fiber cables, fiber optic bundles, spectroscopy fiber optic probes, probe couplers and accessories for process spectroscopy to clients. The Optromix product line is based on over 30 years of unique technology experience, which allows these products to have a broad spectral range from 200 nm to 18 µm.

Optromix optical fibers are used in a wide variety of applications, some of which include spectroscopy and process monitoring tasks, IR radiation delivery to and out of closed volumes, thermosensing, laser power flexible delivery systems, IR-imaging, etc. Along with a regular range of products, the company offers custom optical fiber solutions for non-standard tasks and applications. The aim is to deliver the best quality optical fiber systems, high power fiber cables, and spectroscopy fiber probes & fiber bundles to clients, and our custom solutions meet the needs of a wide range of applications, such as reaction monitoring, biomedicine & biotechnology, IR-Fiber pyrometry, laser technology. If you have any questions or would like to buy an optical fiber, please contact us at info@optromix.com

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