Carefully inspect all hydraulic hose and fittings at regular intervals to ensure airworthiness. Investigate any evidence of fluid loss or leaks. Check metal tubes for leaks, loose anchorage, scratches, kinks, or other damage. Inspect fittings and connections for leakage, looseness, cracks, burrs, or other damage. Replace or repair defective elements. Make sure the hoses do not chafe against one another and are correctly secured and clamped.
a. Replacement of Metal tube. When inspection shows hydraulic hose to be damaged or defective replace the whole line or, if the damaged section is localized, a repair section may be inserted. In replacing aircraft hose, always use tubing of the exact same size and material as the original line. Use the old tubing as a template when bending the brand new tube, unless it's too greatly damaged, in which case a template could be made from soft iron wire. Soft aluminum tubing (1100, 3003, or 5052) under half-inch outside diameter may be bent by hand. For other tubing use a satisfactory hand or power tube-bending tool. Bend tubing carefully to avoid excessive flattening, kinking, or wrinkling. A small amount of flattening in bends is acceptable, but do not exceed 75 percent of the original outside diameter. Excessive flattening can cause fatigue failure of the hydraulic tube. When installing the replacement tubing line it up correctly with the mating part such that it isn't forced into alignment by tightening of the coupling nuts. hydraulic spanner
b. Hose couplings and Tube Connections. Many tube connections are manufactured using flared tube ends with
standard connection fittings: AN-818 (MS 20818) nut and AN-819 (MS 20819) sleeve. In forming flares, slice the tube ends square, file smooth, remove all burrs and sharp edges, and thoroughly clean. The tubing is then flared utilizing the correct 37-degree aviation flare forming tool for how big tubing and kind of fitting. A dual flare is applied to soft aluminum tubing 3/8-inch outside diameter and under, and just one flare on other tubing. To make the connections, use hydraulic fluid as a lubricant and then tighten. Overtightening will damage the tube or fitting, which may result in a failure. Under-tightening may cause leakage which could result in a system failure.
CAUTION: Mistaken utilization of 45-degree automotive flare forming tools may end in improper tubing flare shape and angle; causing misfit, stress and strain, and probable system failure.
c. Repair of aircraft hydraulic Metal Tube Lines. Minor dents and scratches in tubing may be repaired. Scratches or nicks not deeper than 10 percent of the wall thickness in aluminum alloy tubing, which are not in the heel of a bend, may be repaired by burnishing with hand tools. Replace lines with severe die marks, seams, or splits in the tube. Any crack or deformity in a flare is unacceptable and reason for rejection. A dent significantly less than 20 percent of the tube diameter isn't objectionable unless it's in the heel of a bend. A severely-damaged line ought to be replaced; however, it could be repaired by cutting out the damaged section and inserting a pipe part of the exact same size and material. Flare both ends of the undamaged and replacement tube sections and make the text by utilizing standard unions, sleeves, and tube nuts.If the damaged portion is short enough, omit the insert tube and repair by utilizing one union and two sets of connection hose fittings.
d.Replacement of Flexible Hose. When replacement of flexible hose is necessary, utilize the same type, size, part number, and length of hose whilst the line to be replaced. Check TSO requirements. If the replacement of a line with a swaged-end type fitting is necessary, obtain new hydraulic hose assemblies of the correct size and composition. Certain synthetic oils demand a specially compounded synthetic rubber hose, that is compatible. Make reference to the aircraft manufacturer's service information for the correct part number for the replacement hose. If the fittings on each end are of the correct type or sleeve type, an upgraded may be fabricated. Before cutting new flexible wire braided hose to the proper size, tape the hose tightly with masking tape and cut in the biggest market of the masking tape to prevent fraying. The utilization of a mandrel will prevent cutting the interior of the hose when inserting the fittings. Install hose assemblies without twisting. A hose should not be stretched tight between two fittings as this can lead to overstressing and eventual failure. Along hose ought to be sufficient to supply about 5 to 8 percent slack. Avoid tight bends in flex lines as they could end in failure. Never exceed the minimum bend radii.
(1) Teflon hose is found in many aircraft systems because it's superior qualities for certain applications. Teflon is compounded from tetrafluoroethylene resin that is unaffected by fluids normally found in aircraft. It has an operating array of -65°F to 450 °F. For these reasons, Teflon hose is found in hydraulic and engine lubricating systems where temperatures and pressures preclude the utilization of rubber hose. Although Teflon hose has excellent performance qualities, it also has peculiar characteristics that want extra care in handling. It will assume a lasting set when exposed to high pressure or temperature. Don't attempt to straighten a line that has been around service. Any excessive bending or twisting may cause kinking or weakening of the tubing wall. Replace any hose that shows signs of leakage, abrasion, or kinking. Any hose suspected of kinking may be checked with a steel ball of proper size.The ball will not pass through if the hose is distorted beyond limits.
(2) If the hose fittings are of the reusable type, an upgraded hose may be fabricated. Each time a hose assembly is removed, the ends ought to be tied, so that the preformed shape will undoubtedly be maintained.
(3) All flexible hose installations ought to be supported at the very least every 24 inches. Closer supports are preferred. They must be carefully routed and securely clamped to avoid abrasion, kinking, or excessive flexing. Excessive flexing may cause weakening of the hose or loosening at the fittings.
Troubleshooting Hydraulic Machines
Hydraulic machines are found in varied industrial activities today. Without doubt manufacturers of hydraulic machinery are taking keen curiosity about producing the very best machines, which are properly designed, well manufactured and can provide a reliable performance for all years. Any user who uses hydraulic equipments would always like to truly have a trouble free system. But to truly have a hydraulic machine without providing you any trouble sounds too good to be true. Even when the oil or filter is changed regularly, or even if the preventive maintenance program is followed, the equipment is going to stop sooner or later of time. This becomes much more dangerous when it happens in the midst of a production process.
What do you do under this circumstance? It is way better to be prepared for such a scenario so that the work isn't stopped for a long period of time. This is exactly what is referred as troubleshooting your hydraulic machine. Presenting below some easy approaches to hydraulic troubleshooting.
First of all, learn hydraulics, find out how they work because this is the greatest way you are able to handle a problem. Understand how all the tools work, how the system handles pressure, flow and direction, how they're connected to each other. Study the manufacturer's catalog. Gather the maximum amount of information about breakdowns, lists of components, pressure settings, testing points, exactly how many actuators, pumps, valves are found in the system. torcstark wrench
Don't await enough time when the equipment is completely not working. In fact some precautions can be taken even though the equipment is in a working condition. All hydraulic machines operators must follow a
When actually the hydraulic machine stops working, do the following:
- Learn under what circumstances or what caused the equipment to go wrong?
- Was it in the beginning of the cycle?
- Keep in touch with the equipment operator.
- Try to obtain the maximum amount of information as possible.
- Check the hydraulic schematics. Learn the trail from the pump to the actuator. Which actuator or valve was working when the equipment stopped?
- Learn whether you will find any problems in a few components like pumps, some directional valves, some flow controls, relief valves.
- Perform the flow and pressure test adding one more element just like the relief valve after the pump, and so on until you can the cylinder.
As soon as you gather information, its time for you to act. In a nutshell, hydraulic problem solving is not just a quite simple task, but with proper familiarity with hydraulics, with full machine information and equipment, troubleshooting becomes easier and faster.
All About Hydraulic Check Valves
Hydraulic check valves are the absolute most widely used valves that allow fluid to flow in one direction in a hydraulic system and prevent reversal of liquid flow. That's why the name the "check valve" ;.Put simply, this revolutionary product is installed in a pipe so that the water doesn't flow backwards inside the pipe. There is a mechanism inside the pipe which moves based on the flow of the water towards the valve, and when required, the mechanism plugs up the valve opening so that there's no flow of water backwards.
In a hydraulic check valve, you will find two openings. The inlet through which the hydraulic fluid enters and a store through which the fluid goes out. The best thing is which they operate automatically. They work in relation with hydraulic pumps, motors and cylinders. The valves control the flow and pressure of the fluid so that there's proper functioning of the equipment.
You will find different designs for sale in hydraulic valves like ball, plunger, swinging disc, and poppet. Depending on the application area, the size and shape varies. These check valves are found in industrial applications that want hydraulic pumps, like in automotive braking systems, vehicles, construction tools, including city water and sewer systems. They are found in systems where a backup of fluid could create problems on a large scale.
Hydraulic valves are employed for different reasons such as follows:
- The vital role they play is which they prevent flooding when there is extreme back flow of water running through the pipes.
- They avoid the damage of the equipment from water flowing the incorrect direction.
- When the equipment is turned off, the valve helps in steering clear of the fluid from flowing back in the incorrect direction. In exchange, they save power and also protect the pipes from water damage.
- They allow liquid flow in one direction.
- They control fluid pressure.
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