Carefully inspect all hydraulic hose and fittings at regular intervals to ensure airworthiness. Investigate any proof 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 don't 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 entire line or, if the damaged section is localized, a fix section may be inserted. In replacing aircraft hose, always use tubing of the exact same size and material as the first line. Use the old tubing as a template when bending the new tube, unless it's too greatly damaged, where case a template may be produced from soft iron wire. Soft aluminum tubing (1100, 3003, or 5052) under half-inch outside diameter may be bent by hand. For all other tubing use a satisfactory hand or power tube-bending tool. Bend tubing carefully in order to avoid excessive flattening, kinking, or wrinkling. A little bit of flattening in bends is acceptable, but don't exceed 75 percent of the first outside diameter. Excessive flattening will cause fatigue failure of the hydraulic tube. When installing the replacement tubing line it down correctly with the mating part so that it isn't forced into alignment by tightening of the coupling nuts.
b. Hose couplings and Tube Connections. Many tube connections are created using flared tube ends with
standard connection fittings: AN-818 (MS 20818) nut and AN-819 (MS 20819) sleeve. In forming flares, cut 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 is tubing and type of fitting. A dual flare is applied to soft aluminum tubing 3/8-inch outside diameter and under, and just one flare on all other tubing. In making the connections, use hydraulic fluid as a lubricant and then tighten. Overtightening will damage the tube or fitting, that might result in a failure. Under-tightening may cause leakage which could create a system failure.
CAUTION: Mistaken usage of 45-degree automotive flare forming tools may end up 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 should be replaced; however, it may be repaired by cutting out the damaged section and inserting a tube area of the exact same size and material. Flare both ends of the undamaged and replacement tube sections and make the bond by using standard unions, sleeves, and tube nuts.If the damaged portion is short enough, omit the insert tube and repair by using one union and two sets of connection hose fittings. Best Bolting Tools Manufacturer.
d.Replacement of Flexible Hose. When replacement of flexible hose is necessary, utilize the same type, size, part number, and amount 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, which can be compatible. Refer 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 appropriate size, tape the hose tightly with masking tape and cut in the biggest market of the masking tape to stop fraying. The utilization of a mandrel will prevent cutting the interior of the hose when inserting the fittings. Install hose assemblies without twisting. A line shouldn't be stretched tight between two fittings as this will result in overstressing and eventual failure. The size of hose should be sufficient to offer about 5 to 8 percent slack. Avoid tight bends in flex lines as they could end up in failure. Never exceed the minimum bend radii.
(1) Teflon hose is used in many aircraft systems because it has superior qualities for many applications. Teflon is compounded from tetrafluoroethylene resin which can be unaffected by fluids normally used in aircraft. It has an operating selection of -65°F to 450 °F. For these reasons, Teflon hose is used 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 need extra care in handling. It has a tendency to assume a permanent set when subjected to high pressure or temperature. Do not attempt to straighten a line that has been in 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 material ball of proper size.The ball will not move across if the hose is distorted beyond limits.
(2) If the hose fittings are of the reusable type, an upgraded hose may be fabricated. When a hose assembly is removed, the ends should be tied, so your preformed shape is likely to be maintained.
(3) All flexible hose installations should be supported at least every 24 inches. Closer supports are preferred. They must be carefully routed and securely clamped in order 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 used in varied industrial activities today. Undoubtedly manufacturers of hydraulic machinery are taking keen fascination with producing the best machines, which are smartly designed, well manufactured and can give a reliable performance for a lot of 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 giving you any trouble sounds too good to be true. Even though the oil or filter is changed regularly, or even if the preventive maintenance program is followed, the device will probably stop at some point of time. This becomes much more dangerous when it happens in the midst of a creation process.
What do you do under this circumstance? It is much better to be equipped for such a situation so your work isn't stopped for an extended period of time. This is what is referred as troubleshooting your hydraulic machine. Presenting below some easy ways to hydraulic troubleshooting.
First of all, learn hydraulics, learn how they work since this is the best way you are able to handle a problem. Understand how all the tools work, how the device handles pressure, flow and direction, how they're connected to each other. Study the manufacturer's catalog. Gather just as much information regarding breakdowns, lists of components, pressure settings, testing points, how many actuators, pumps, valves are used in the system. TorcStark
Do not watch for the full time when the device is completely not working. In fact some precautions can be taken even though the device is in a working condition. All hydraulic machines operators must follow a
When actually the hydraulic machine stops working, do the following:
- Discover under what circumstances or what caused the device to are amiss?
- Was it at the start of the cycle?
- Talk to the device operator.
- Try to have just as much information as possible.
- Check the hydraulic schematics. Discover the road from the pump to the actuator. Which actuator or valve was working when the device stopped?
- Discover whether you will find any problems in some components like pumps, some directional valves, some flow controls, relief valves.
- Perform the flow and pressure test adding an additional element just like the relief valve following the pump, and etc until you're able to the cylinder.
Once you gather information, its time to act. In a nutshell, hydraulic problem solving is not 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 trusted valves that enable fluid to flow in one direction in a hydraulic system and prevent reversal of liquid flow. That is why the name the "check valve" ;.In other words, this revolutionary product is installed in a tube so your water does not flow backwards within the pipe. There's a mechanism within 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 surely is no flow of water backwards.
In a hydraulic check valve, you will find two openings. The inlet through that the hydraulic fluid enters and an outlet through that the fluid goes out. A good thing is 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 surely is proper functioning of the equipment.
There are different designs available in hydraulic valves like ball, plunger, swinging disc, and poppet. With regards to the application area, the size and shape varies. These check valves are used in industrial applications that need hydraulic pumps, like in automotive braking systems, vehicles, construction tools, including city water and sewer systems. They are used in systems where a backup of fluid could cause problems on a sizable scale.
Hydraulic valves are useful for different reasons such as for instance follows:
- The vital role they play is they prevent flooding when there is extreme back flow of water running through the pipes.
- They avoid the damage of the device from water flowing the wrong direction.
- When the device is turned off, the valve helps in preventing the fluid from flowing back in the wrong direction. In return, 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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