When installing the hose assembly to equipment and piping, it is necessary to pay attention to the following items.
１: Confirmation of storage period
Prior to use, the date of manufacture of the hose assembly should be checked, and if one year or more has passed since manufacture, necessary inspections and tests should be carried out in principle to ensure safety.Although it depends on storage conditions, usage conditions, etc., it is generally desirable not to use products that have been manufactured for two years or more.
２: Length setting
The length of the hose assembly should be adjusted so that it does not hang excessively and interfere with other parts when installed.In addition, taking into consideration expansion and contraction during pressurization, the hose assembly should be of an appropriate length so that it will not be subjected to tensile or other harmful loads, nor will it be bent below the specified minimum bending radius.
２-１: When using in a straight line
The length of the hose assembly should have a margin corresponding to the change in the length of the hose so that the hose assembly will not be subjected to abnormal tension when pressure is applied. .
* L = (１ + rate of change in length) x Y
L: Length of hose assembly
Y: Use straight line distance
L: Length of hose assembly
Y: Use straight line distance
２-２: When using by bending with both ends fixed
When both ends of the hose assembly are fixed and bent, the center distance between the parallel parts of both ends of the hose assembly bent into a U shape shall not be smaller than the sum of twice the specified minimum bend radius and the outer diameter of the hose.Also, his L-bent hose assembly provides the length of the straight part as much as possible, and adds the outer diameter dimension of the hose so that it does not bend sharply from the end of the joint. is as follows.
When bent into a U shape | When bent into an L shape |
L=π(r+D/2)+2A | L = π/2 (r + D/2) + 2A + i |
L : Free length of hose π: Circumference ratio r : Minimum bending radius of hose D: Maximum outer diameter of hose | L : Free length of hose π: Circumference ratio r : Minimum bending radius of hose D: Maximum outer diameter of hose i : Length of straight part of hose |
２-３: When one end moves
Required free length of hose when a portion of the U-bent hose assembly travels a distance T
L=π(r+D/２)+２A+T
L : Free length of hose
π: Circumference ratio
r : Minimum bending radius of hose
D: Maximum outer diameter of hose
T : Travel
L : Free length of hose
π: Circumference ratio
r : Minimum bending radius of hose
D: Maximum outer diameter of hose
T : Travel
hose Size | 6 | 9 | 12 | 15 | 19 | 25 | 32 | 38 | 50 |
-04 | -06 | -08 | -10 | -12 | -16 | -20 | -24 | -32 | |
mm | 30 | 40 | 40 | 60 | 70 | 80 | 100 | 120 | 140 |
３: Repeated bending
If the hose assembly undergoes repeated bending motions, the fatigue of the hose will increase and the service life will be shortened.
４: twist
If the hose assembly is repeatedly pressurized while it is twisted, deformation will occur in the vicinity of the end of the joint of the hose, which cannot absorb the twist, or in the reinforcing layer of the straight portion, which may cause the hose to burst or the joint to be twisted and loosened. increase.
When installing the hose assembly, care must be taken to ensure that it is not twisted and that the hose assembly does not become twisted during operation of the equipment.
When installing the hose assembly, care must be taken to ensure that it is not twisted and that the hose assembly does not become twisted during operation of the equipment.
４-１: Torsion due to joint thread type
Hose assemblies with screw seal type joints, such as R (PT) screws fixed at both ends, may twist during installation, so it is better to use joints with union nuts at one or both ends of the joint. good.
When installing, check the hose mark printed on the hose to see if it is twisted.
When installing, check the hose mark printed on the hose to see if it is twisted.
４-２: Torsion when bending in three dimensions
When the hose assembly is used by bending in three dimensions, twisting occurs when pressurized.
Especially when moving, since twisting occurs, use an accessory or the like to bend the hose assembly in the same plane to prevent twisting of the hose assembly.
Especially when moving, since twisting occurs, use an accessory or the like to bend the hose assembly in the same plane to prevent twisting of the hose assembly.
４-３: Torsion when one end moves
Twisting occurs when one end of a hose assembly attached in a U-bend moves in a plane different from the mounting plane of the hose assembly.
In this case, the hose assembly is installed in the moving direction of the moving equipment and piping to prevent twisting.
In this case, the hose assembly is installed in the moving direction of the moving equipment and piping to prevent twisting.
４-４: Torsion when vibrating differently
Although it is a special case, when the joints at both ends of the hose assembly vibrate in different planes, premature damage may occur due to twisting. Separate it so that each part moves in its own plane.
５: Arrangement
Install the hose assembly carefully so that it does not interfere with other equipment, piping, etc. and cause wear or damage to hoses and joints.In addition, it should be arranged so that inspection and repair can be easily performed after installation.
６: protection
When installing the hose assembly, if it is unavoidably used in excess of the above items or the hose assembly regulations due to design or other reasons, it may cause premature damage. Is required.
６-１: In the case of a sharp bend
If the hose assembly bends sharply from the end of the fitting, or if the bend radius of the hose is smaller than the specified minimum bend radius of the hose assembly, use fittings to change the mounting angle or adjust the fitting. Sudden bends must be prevented by, for example, attaching protective springs to the bends in the hose from the assembly.
There should be no gap between the joint of the protection spring and the end of the hose.
There should be no gap between the joint of the protection spring and the end of the hose.
６-２: When twisting or sharp bending is unavoidable
If the hose assembly is twisted or sharply bent as described in ６-１, use a swivel joint to prevent the hose assembly from twisting or sharply bending.
６-３: When there is interference
If the hose assembly inevitably interferes with others, install a resin cover, exterior braid, protective spring, etc. to prevent injury due to interference, or fix the hose assembly using brackets, clamps, etc. to avoid interference. Appropriate interference prevention measures are required.
* The main examples and countermeasures in case of interference are shown.
① When piping a hose assembly, be sure to measure the bending radius at the point where pressure is applied to the hose.
Since the hose may move as the pressure rises, in order to suppress this change, the curved part of the hose is not fixed and protected with an exterior braid and protective spring.
② Do not allow the hose to hit sharp objects.
Prevent hose contact by installing clamps at short intervals.
③ Make sure that the hose does not hit the exercise equipment.
④ Avoid unnecessary contact of the entire hose
If the hoses are in contact with each other, it will cause injury and cause the hose to burst, so install a jig to avoid contact.
７: Installation of hose assembly
When using the hose assembly again after removing it for inspection or repair of equipment or circuits, pay attention to the following.
① If the hose is bent in the opposite direction to avoid bending and reinstalled, cracks will form in the rubber layer and the service life of the hose assembly will be drastically reduced.
② Use air to remove foreign matter from contact areas such as joint threads and seat surfaces, clean them, and reuse them.
② Use air to remove foreign matter from contact areas such as joint threads and seat surfaces, clean them, and reuse them.
８: Tightening torque of threaded joint
The tightening torque for the threads of union joints and union adapters with parallel pipe threads (G, old PF) is shown in the table below.
If screws are tightened with proper tightening torque, they will not loosen or leak during use.If fluid leaks from the seal, do not tighten it forcibly, and check the seat surface for dust or scratches.Forcibly tightening may damage the contact part of the joint.
The screw joint should be tightened with a torque wrench as securely as possible, with an appropriate tightening torque value, and when it is unavoidable for work, use a spanner specified by JIS, and do not use a monkey wrench.
In addition, it is necessary to consult with the assembly manufacturer regarding the tightening torque of other screws.
If screws are tightened with proper tightening torque, they will not loosen or leak during use.If fluid leaks from the seal, do not tighten it forcibly, and check the seat surface for dust or scratches.Forcibly tightening may damage the contact part of the joint.
The screw joint should be tightened with a torque wrench as securely as possible, with an appropriate tightening torque value, and when it is unavoidable for work, use a spanner specified by JIS, and do not use a monkey wrench.
In addition, it is necessary to consult with the assembly manufacturer regarding the tightening torque of other screws.
Table: G screw tightening torque
Call | pipeparallel Nominal of screw | tightening torque N・m | Applicable pressure range MPa |
5 · 6 | 1/4 | 25 | 34.5 |
8 · 9 | 3/8 | 34 | 34.5 |
12 | 1/2 | 64 | 34.5 |
15 · 19 | 3/4 | 132 | 27.5 |
25 | 1 | 196 | 27.5 |
32 | 11/4 | 225 | 17.0 |
38 | 11/2 | 255 | 10.5 |
50 | 2 | 316 | 10.5 |
