JPH02548Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to the structure of a double jacket hose used for firefighting and the like. General fire hoses are made by forming a rubber or synthetic resin lining on the inner surface of a jacket woven into a cylindrical shape using fibers for warp and weft.
All kinds of cloth hoses are used. This cloth hose is light and flexible, can be rolled into a coil for compact transportation and storage, and has high pressure resistance, making it particularly suitable for fire fighting. Furthermore, for fire hoses that are used under particularly high pressure, double-jacketed hoses are used in order to improve pressure resistance and prevent reduction in pressure resistance due to external damage. In particular, in recent years, in order to prevent water damage caused by firefighting activities, spray water using high-pressure water has been proposed.
A double-jacketed hose with a small diameter of about mm is used. The double jacket hose is constructed by using the fabric hose as an inner tube hose, and fitting an outer jacket having a similar structure to the jacket on the outside thereof. Conventionally, the design concept of this type of double jacket hose was that the inner cylinder and outer cylinder jacket were in close contact with each other, and when pressure was applied to the double jacket hose, the inner cylinder jacket and the outer cylinder jacket were in contact with each other. It was considered preferable to use a material that could bear the pressure evenly. Therefore, normally, the inner diameter of the inner cylinder and the outer jacket of the outer cylinder are made to almost match, and when pressurizing, tension is applied equally to the weft threads of the jacket of the inner cylinder and the jacket of the outer cylinder, so that the pressure increases. Therefore, the tension force is increased equally in the inner cylinder and the outer cylinder jacket, and the design is such that the inner cylinder and the outer cylinder break at the same time when the jacket breaks. This type of fire hose was considered to be the most superior with the highest pressure resistance. By the way, in the past, double-jacketed hoses were often used mainly for large-diameter high-pressure hoses near pumps, but in recent years, as mentioned above, they have been used for small-diameter hoses for spraying water, When used nearby, hoses are often dragged along the ground.
Opportunities for injuries from sharp glass pieces, metal pieces, nails, etc. have increased. Conventionally, double jacketed hoses were thought to have good trauma resistance, but as they are exposed to more trauma, it has become clear that they are not as resistant to trauma as previously thought. . In other words, in a pressurized state, the weft threads of the inner jacket and outer jacket are under strong tension, and if a sharp piece of glass or the like comes into contact with this, the weft thread of the outer jacket can easily be cut. The damage easily extends to the jacket of the inner cylinder. The present invention was devised in view of the above circumstances, and it is an object of the present invention to provide a double jacket hose with improved trauma resistance by adjusting the diameters of the inner jacket and the outer jacket. It is. Therefore, in the present invention, in the double jacket hose, the inner tube hose and the outer tube jacket are not bonded together, and the inner diameter of the outer tube jacket when no pressure is applied or when pressurized is the same as that of the inner tube hose. The outer diameter is approximately equal to or slightly larger than the outer diameter when pressurized to the design working pressure of the double jacket hose alone, and the weft thread of the outer jacket is not tensioned when the double jacket hose is used. It is something to do. The drawing shows a double jacket hose of the present invention, where 1 is an inner tube hose, and 2 is a jacket of the inner tube hose. The jacket 2 is made by weaving warp yarns 3 and weft yarns 4 into a cylindrical shape, and 5 is an airtight lining bonded to the inner surface of the jacket. Reference numeral 6 denotes an outer jacket, which is made by weaving warp yarns 7 and weft yarns 8 into a cylindrical shape. Specific embodiments of the present invention will be described below. First, the jacket 2 of the inner cylinder hose 1 is used as the warp thread 3.
184 yarns made by twisting 8 strands of 20 count polyester spun yarn together, and 184 yarns made by pulling 2 yarns together, and the weft yarn was 10cm yarn made by twisting 3 strands of 1500d polyester filament yarn. It was woven by inserting 50 threads in between. Lining 5 is
An airtight film of a suitable rubber or synthetic resin is formed on the inner surface of the jacket 2 by a known method. The outer diameter of this inner cylinder hose 1 was 43.1 mm when pressurized to 0.5 Kg/cm ² , and the pressure resistance was 54 Kg/cm ² . When pressurized further, the outer diameter of the inner cylinder hose 1 changed as follows. Pressure (Kg/cm ² ) Outer diameter (mm) 0.5 43.1 2 43.4 5 43.9 10 44.7 16 45.6 20 46.2 The outer jacket 6 uses, as the warp 7, a thread made of six 20 count polyester spun yarns twisted together. 205 strands are used, with 8 wefts.
For this purpose, two strands of 1000 d polyester filament yarn were twisted together at a rate of 58 threads per 10 cm. Outer jacket 6 with the above configuration
, the inner diameter when pressurized with 0.5Kg/ ^cm2 is 48.0mm, respectively.
Three types of double jacket hose samples were prepared by weaving the hoses to a length of 46.0 mm and 43.5 mm, respectively, and fitting them to the outside of the inner cylinder hose 1. Next, each double jacket hose was subjected to a trauma test, and the change in breaking pressure before and after the test was measured. In this test, the method of applying trauma to the double jacket hose was as follows:
A 2 kg load is applied to a 5 mm long nail, and the nail is placed on the surface of a double jacket hose that has been applied with water pressure of 16 kg/cm ² , which is the designed working pressure, and the nail is placed in the longitudinal direction of the double jacket hose. This was repeated 10 times at the same location on the same double jacket hose. The results of the test were as shown in the table below.

[Table] In a sample in which the inner diameter of the outer cylinder jacket 6 is 48.0 mm, the outer diameter of the inner cylinder hose 1 when pressurized with 16 kg/cm ² is 45.6 mm, so even in the pressurized state, the inner cylinder hose 1 is The outer surface does not line up with the inner surface of the outer cylinder jacket 6, and the outer cylinder jacket 6 is loosely fitted to the inner cylinder hose 1.
I haven't felt any tension at all. In this sample, despite the severe trauma test described above, the rupture pressure before the test hardly decreased even after the test. In addition, in a sample in which the inner diameter of the outer jacket 6 is 46.0 mm, when the double jacket hose is pressurized, the inner jacket 1 and the outer jacket 6 are barely in close contact, and the outer jacket 6 is almost in contact with each other. Although it is in a state of expanded pressure into a cylindrical shape, there is almost no tension. In this double jacket hose, the bursting pressure before the trauma test is higher than in the previous example, so although the drop in bursting pressure due to the trauma test is slightly larger, the bursting pressure after the test is about the same as the previous example. be. On the other hand, the inner diameter of the outer cylinder jacket 6 is 43.5 mm.
The sample has the same structure as a conventional double jacket hose, and the inner tube hose 1 and the outer tube jacket 6 are in close contact even when no pressure is applied, and when the pressure is applied, the outer tube jacket 6 is closed due to the internal pressure. I'm in a tense state. In the double jacket hose of this example, the outer jacket 6 also bears the pressure resistance along with the inner jacket 1, so the burst pressure before the trauma test is the highest among the three types of samples, but the fracture pressure decreases due to the trauma test. is the most remarkable, and the breaking pressure after the test is the lowest among the three types of samples, and is even lower than the breaking pressure of the inner cylinder hose 1 alone. That is, in this sample, it is clear that the external damage penetrated through the outer jacket 6 and reached the inner hose 1. As is clear from the above description, in the first two examples, which are embodiments of the present invention, the withstand pressure before receiving trauma is lower than in the third example, which is a conventional example, but It is not easily damaged by glass pieces, metal pieces, nails, etc., and its pressure resistance does not decrease.
This double-jacketed hose is especially suitable for use as a firefighting hose near the tip of the tube, which is used while dragging on rough ground. In the present invention, it is necessary that the weft thread of the outer jacket is not under tension when the hose is pressurized to the operating pressure. The tension in the weft thread makes it extremely easy to break the weft thread when it comes into contact with a sharp piece of glass or metal. Therefore, when the hose is not pressurized or pressurized at low pressure, the inner diameter of the outer jacket must be larger than the outer diameter of the inner jacket, and the inner diameter of the inner jacket alone can exceed the working pressure of a double jacket hose. It is preferable that the outer diameter is approximately equal to or slightly larger than the outer diameter when pressurized. To be specific about a double jacket hose that uses polyester filament yarn as the normal weft thread, the inner diameter of the outer jacket when no pressure is applied is about 4 to 15 degrees larger than the outer diameter of the inner jacket when no pressure is applied. For a hose with a nominal diameter of 40 mm, it is appropriate that the difference be approximately 2 to 6 mm. Although the double-jacket hose of the present invention has a lower pressure resistance before being subjected to external injury than the conventional double-jacket hose, this cannot be said to be a drawback. In other words, with conventional hoses, even after the withstand pressure has decreased due to external injury, etc., in order to ensure sufficient withstand pressure to withstand use, a breaking pressure that is much higher than the operating pressure is required. Therefore, in the present invention, since the drop in the breaking pressure due to external trauma is small, there is no need to make the breaking pressure higher than necessary.

[Brief explanation of the drawing]

The drawing is a partially cutaway perspective view of the double jacket hose of the present invention. 1... Inner tube hose, 2... Jacket, 5...
Lining, 6...outer jacket.

Claims (1)

[Scope of utility model registration request] A double jacket hose made by fitting an outer jacket made of fibers woven into a cylinder on the outside of an inner jacket made of an inner jacket made of fibers woven into a cylinder and lined with rubber or synthetic resin on the inner surface. In this case, the inner tube hose and the outer tube jacket are not bonded, and the inner diameter of the outer tube jacket when no pressure is applied or when pressurized at low pressure is such that the inner tube hose alone does not meet the design working pressure of the double jacket hose. Approximately equal to or slightly larger than the outer diameter when pressurized,
A double jacket hose, characterized in that the weft of the outer jacket is not tensioned when the double jacket hose is used.