CA1078308A - Hose construction - Google Patents
Hose constructionInfo
- Publication number
- CA1078308A CA1078308A CA272,191A CA272191A CA1078308A CA 1078308 A CA1078308 A CA 1078308A CA 272191 A CA272191 A CA 272191A CA 1078308 A CA1078308 A CA 1078308A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- hose
- core tube
- tenacity
- room temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
Abstract of the Disclosure A flexible reinforced hose for conveying fluids under a high pressure is disclosed. The hose includes a synthetic polymeric core tube, a first layer of fibrous reinforcing material having a tenacity of from 12 to 25 grams per denier, and a second layer of reinforcing material having a tenacity less than that of the first layer.
Description
l07s3a~
Bac~ground of the Invention Field of the Invention .' ':
This invention relates to flexible hydraulic hose, and more particularly to hydraulic hose which can withstand ~;
high pressure, maintain flexibility, and which can be -assembled to couplings designed for other hoses.
Description of the Prior Art Flexible hoses made of elastomeric or flexible plastic materials require reinforcement by material such as rk) ~- ~
10~ braided, helically wound, or knitted rayon, Dacro~, stainless steel wire, or the like when the hoses are to be used for conveying fluids under high pressure, such as hydraulic pressures over 1,000 psi. For small diameter hoses, such as hoses having an inner diameter of 1/4", one layer of reinforcement material may be sufficient to give the hose a burst strength of up to 6,000 psi, depending upon the extent of coverage provided by the reinforcement, and the reinforcement material used. For larger diameter hoses, such as hoses having an inner diameter larger than 1/4", more than one layer of reinforcement material is usually required to provide a high burst strength.
When two or more layers of reinforcement material are used, several problems arise. If the reinforcement material is steel wire applied at a conventional braid angle o~ approximately 54, the burst strength of the hose is high, however, there is little expansion or elongation of the reinforcement material, and upon application of internal fluid pressure to the hose, the first reinforcement layer does not stretch a sufficient amount to transfer a substantial . .
part o~ the load to the second reinforcement layer. In addition, the rigidity of the steel wire and the resultant resistance to elongation and expansion of the hose under hydraulic shock pressures results in the hose failing to cushion or dilssipate such shock pressures, which may have adverse effects on the other parts of the hydraulic system.
In contrast, if a fibrous non-metallic material (irq.,a ~774~) E such as Nylon 6/6, Dacro~, rayon, or the like is used as the reinforcement material, the expansion or elongation of the reinforcement material is higher, and when hydraulic shock pressures occurr the reinforcement material yields to a greater extent that steel wire and the insides of the hose may increase in volume to the extent that sluggish or spongy reaction of other components in the hydraulic system will occur.
An additional disadvantage of steel wire reinforce-ment is that the hose is stiff and relatively infleXible.
When a conventional fibrous non-metallic reinforcement rrqrk~
material such as ~ylon 6/6, Dacron~ rayon, or the like is used, the hose is more flexible but may be subject to excessive elongation or expansion.
The aforementioned problems were overcome in co-pending canadian patent application No. 224,898 filed on April 17, 1975 in the name of Parker-Hannifin Corporation by the use of two layers of a braided fibrous aromatic nylon yarn that is available from the E.I. duPOnt de Ne~mours Company under the trade mark Kevlar and which was formerly designated by duPont as Fiber B ~ylon. These two layers of Kevlar replace the other reinforcement layers used in the prior art. The use "~
. .
`` 1(~7830~
of two layers of Kevlar results in a relatively flexible hose having a very high burst strength and which can dissipate shock pressures without causing system sluggishness or spon-giness. The disadvantage of such a hose construction is that it is relatively expensive due to the high cost of the Kevlar material. However, because of the high strength of Kevlar, a single layer of Kevlar reinforcement material may provide suf-ficient strength for some applications that would otherwise require two layers of some other non-metallic reinforcement material. The use of a single layer of Kevlar in such an application minimizes the cost problem associated with this material, but results in a hose with a smaller total wall thickness than hoses using two layers of other reinforcement material. Thus, a hose using a single layer of Kevlar would require a different set of couplings than those used by hoses of another construction. In addition, the smaller wall thick-ness results in the hose having less resistance to kinking.
-S-ummary of the;Invention The present invention provides a solution to the aforementioned problems of hose strength, flexibility, dissi-pation of shock pressures, hydraulic system sluggishness, cost, utilization of existing couplings and kinking. This is accom-plished by providing a hose with a synthetic polymeric core tube, a first layer of Kevlar reinforcement material about the core tube, a second layer of some other less expensive fibrous reinforcement material over the Kevlar reinforcement material, and a sheath of synthetic polymeric material over the less expensive reinforcement material.
According to the present invention, there is provi-ded a high burst strength flexible composite reinforced hose for conveying fluids under pressure comprising a synthetic polymeric core tube, a first layer o fibrous reinforcing ~-material disposed adjacent the core tube having synthetic E
10783()8 .
filaments having a tenacity at room temperature of from 15 to about 25 grams per denier, and another layer of reinforcing material over the first layer and formed of composite fibers having a tenacity at room temperature less than that of said first layer.
Brief Descripti~n of the Drawings Figure 1 illustrates a side elevation, partly broken away in successive structural layers, of a hose made .........
-4a-E
.. . ............. .. ... ~ ~ . . .
. . .. . ...... . .. ~ ..... .
_ 5 - 1~7830~
in accordance with the present invention.
,:
Description of the Preferred Embodiment .
A hose constructed in accordance with this invention is illustrated in figure 1. This figure illustrates a hose 10 having a core tube 12 of synthetic polymeric material, a first layer of reinforcement material 14 comprising composite fibers, a second layer of reinforcement material 16 of composite fibers, and an outer sheath 18 of synthetic polymeric material. The material utilized to form the core tube 12 and the outer sheath 18 may be selected from any of the well-known synthetic polymers used in the hose :
industry to produce reinforced hoses, such as Nylon 6/66, Jc Jnc~rkJ ~
Nylon 11, Hytre~, polyurethane, or the like. The selection of the particular material used for the core tube and sheath will depend upon the end use and the properties desired of the hose. The material selected for the sheath 18 may be the same or different from the material chosen for the core tube 12.
The first reinforcing layer 14 is composed of Kevlar material which has a modulus of elasticity of between 400 and 500 grams per denier at room temperature and at least 300 grams per denier at 300F. Its tenacity is between 15 and 25 grams per denier at room temperature, and over 10 grams per denier at 260F. At room temperature, Kevlar has an elongation at break of about 4%. The density of the yarn is between 1.40 and 1.50 and the tensile strength is about 405,000 psi.
The second reinforcing layer 16 is composed of synthetic filaments having a tenacity lower than that of 30 E Kevlar, such as Nylon 6/6, rayon, or Dacron~C, whlch is 6- ~1~783()~3 `
:. ' either a polyethylene terephthalate ester or a polyalkylene terephthalate ester. These materials have a tenacity of about 7 to 11 grams per denier.
:
Both the first and second reinforcing layers may be either braided or helically wound. In the case of a ~-;helically wound reinforcement, one strand is helically wound ; on the core tube in one direction and another strand is helically wound over the first strand in the opposite direction and the two strands together comprise one layer of reinforcement material. The first reinforcing layer may or may not be bonded to the core tube and the second reinforsing layer may or may not be bonded to the first reinforcing layer and/or the sheath. However, in the preferred embodiment of the invention, there is no bon~
between the first and second reinforcing layers, but there is a bond between the second layer and the sheath. Any suitable method may be used for bonding the various layers together such as epoxy adhesives, polyurethane adhesives, or solvents.
The Kevlar yarn imparts greater radial and axial dimensional stability to the hose when subjected to fluid pressure than hoses having reinforcement layers of Nylon 6/6, -Dacron, rayon and other non-metallic fibrous materials heretofore used because it has a substantially higher modulus and a lower elastic elongation value than those other materials.
The lower elastic elongation, however, still permits sufficient expansion of the first reinforcement layer to allow some sharing of the load by the second reinforcement layer, but the expansion is less than that of Nylon 6/6, Dacron, rayon, or the like so that hydraulic system sluggishness or sponginess is minimi~ed.
107l~308 On the other hand, because the elastic elongation of Kevlar i5 substantially greater than that of steel wire, the expansion in volume under fluid pressure of the hose -having a Kevlar reinforcement layer is greater than that of a hose having a steel wire reinforcement layer. Thus, `~-a hose using Kevlar as the reinforcement material cushions or dissipates hydraulic shocks to a greater degree than a hose with steel reinforcement.
Although the second reinforcing layer, which is of material other than Kevlar, shares part of the load, it also functions as a filler to increase the wall thickness of the hose so that the hose can be assembled to standard co~plings. (Use of a second layer of Xevlar to increase the wall tllickness so that the hose can be assembled to standard couplings is not economical because, as previously mentioned, Kevlar is more expensive than ~ylon 6/6, Dacron, rayon, or the like.) In addition, the second reinforcing layer prevents crushing of the Kevlar layer when the coupling is attached since it is not as brittle as Kevlar. Also, by reinforcing the hose structure, the second layer also minimizes hose kinking. It should be noted that the hose can be constructed with or without an outer sheath. When constructed without an outer sheath, the hose is very flexible since the material used for the second reinforcing layer is more flexible than that used for the outer sheath.
Variations of the present invention will be apparent to those having ordinary skill in the art and the invention -~
is limited only by the spirit and scope of the following claims.
Bac~ground of the Invention Field of the Invention .' ':
This invention relates to flexible hydraulic hose, and more particularly to hydraulic hose which can withstand ~;
high pressure, maintain flexibility, and which can be -assembled to couplings designed for other hoses.
Description of the Prior Art Flexible hoses made of elastomeric or flexible plastic materials require reinforcement by material such as rk) ~- ~
10~ braided, helically wound, or knitted rayon, Dacro~, stainless steel wire, or the like when the hoses are to be used for conveying fluids under high pressure, such as hydraulic pressures over 1,000 psi. For small diameter hoses, such as hoses having an inner diameter of 1/4", one layer of reinforcement material may be sufficient to give the hose a burst strength of up to 6,000 psi, depending upon the extent of coverage provided by the reinforcement, and the reinforcement material used. For larger diameter hoses, such as hoses having an inner diameter larger than 1/4", more than one layer of reinforcement material is usually required to provide a high burst strength.
When two or more layers of reinforcement material are used, several problems arise. If the reinforcement material is steel wire applied at a conventional braid angle o~ approximately 54, the burst strength of the hose is high, however, there is little expansion or elongation of the reinforcement material, and upon application of internal fluid pressure to the hose, the first reinforcement layer does not stretch a sufficient amount to transfer a substantial . .
part o~ the load to the second reinforcement layer. In addition, the rigidity of the steel wire and the resultant resistance to elongation and expansion of the hose under hydraulic shock pressures results in the hose failing to cushion or dilssipate such shock pressures, which may have adverse effects on the other parts of the hydraulic system.
In contrast, if a fibrous non-metallic material (irq.,a ~774~) E such as Nylon 6/6, Dacro~, rayon, or the like is used as the reinforcement material, the expansion or elongation of the reinforcement material is higher, and when hydraulic shock pressures occurr the reinforcement material yields to a greater extent that steel wire and the insides of the hose may increase in volume to the extent that sluggish or spongy reaction of other components in the hydraulic system will occur.
An additional disadvantage of steel wire reinforce-ment is that the hose is stiff and relatively infleXible.
When a conventional fibrous non-metallic reinforcement rrqrk~
material such as ~ylon 6/6, Dacron~ rayon, or the like is used, the hose is more flexible but may be subject to excessive elongation or expansion.
The aforementioned problems were overcome in co-pending canadian patent application No. 224,898 filed on April 17, 1975 in the name of Parker-Hannifin Corporation by the use of two layers of a braided fibrous aromatic nylon yarn that is available from the E.I. duPOnt de Ne~mours Company under the trade mark Kevlar and which was formerly designated by duPont as Fiber B ~ylon. These two layers of Kevlar replace the other reinforcement layers used in the prior art. The use "~
. .
`` 1(~7830~
of two layers of Kevlar results in a relatively flexible hose having a very high burst strength and which can dissipate shock pressures without causing system sluggishness or spon-giness. The disadvantage of such a hose construction is that it is relatively expensive due to the high cost of the Kevlar material. However, because of the high strength of Kevlar, a single layer of Kevlar reinforcement material may provide suf-ficient strength for some applications that would otherwise require two layers of some other non-metallic reinforcement material. The use of a single layer of Kevlar in such an application minimizes the cost problem associated with this material, but results in a hose with a smaller total wall thickness than hoses using two layers of other reinforcement material. Thus, a hose using a single layer of Kevlar would require a different set of couplings than those used by hoses of another construction. In addition, the smaller wall thick-ness results in the hose having less resistance to kinking.
-S-ummary of the;Invention The present invention provides a solution to the aforementioned problems of hose strength, flexibility, dissi-pation of shock pressures, hydraulic system sluggishness, cost, utilization of existing couplings and kinking. This is accom-plished by providing a hose with a synthetic polymeric core tube, a first layer of Kevlar reinforcement material about the core tube, a second layer of some other less expensive fibrous reinforcement material over the Kevlar reinforcement material, and a sheath of synthetic polymeric material over the less expensive reinforcement material.
According to the present invention, there is provi-ded a high burst strength flexible composite reinforced hose for conveying fluids under pressure comprising a synthetic polymeric core tube, a first layer o fibrous reinforcing ~-material disposed adjacent the core tube having synthetic E
10783()8 .
filaments having a tenacity at room temperature of from 15 to about 25 grams per denier, and another layer of reinforcing material over the first layer and formed of composite fibers having a tenacity at room temperature less than that of said first layer.
Brief Descripti~n of the Drawings Figure 1 illustrates a side elevation, partly broken away in successive structural layers, of a hose made .........
-4a-E
.. . ............. .. ... ~ ~ . . .
. . .. . ...... . .. ~ ..... .
_ 5 - 1~7830~
in accordance with the present invention.
,:
Description of the Preferred Embodiment .
A hose constructed in accordance with this invention is illustrated in figure 1. This figure illustrates a hose 10 having a core tube 12 of synthetic polymeric material, a first layer of reinforcement material 14 comprising composite fibers, a second layer of reinforcement material 16 of composite fibers, and an outer sheath 18 of synthetic polymeric material. The material utilized to form the core tube 12 and the outer sheath 18 may be selected from any of the well-known synthetic polymers used in the hose :
industry to produce reinforced hoses, such as Nylon 6/66, Jc Jnc~rkJ ~
Nylon 11, Hytre~, polyurethane, or the like. The selection of the particular material used for the core tube and sheath will depend upon the end use and the properties desired of the hose. The material selected for the sheath 18 may be the same or different from the material chosen for the core tube 12.
The first reinforcing layer 14 is composed of Kevlar material which has a modulus of elasticity of between 400 and 500 grams per denier at room temperature and at least 300 grams per denier at 300F. Its tenacity is between 15 and 25 grams per denier at room temperature, and over 10 grams per denier at 260F. At room temperature, Kevlar has an elongation at break of about 4%. The density of the yarn is between 1.40 and 1.50 and the tensile strength is about 405,000 psi.
The second reinforcing layer 16 is composed of synthetic filaments having a tenacity lower than that of 30 E Kevlar, such as Nylon 6/6, rayon, or Dacron~C, whlch is 6- ~1~783()~3 `
:. ' either a polyethylene terephthalate ester or a polyalkylene terephthalate ester. These materials have a tenacity of about 7 to 11 grams per denier.
:
Both the first and second reinforcing layers may be either braided or helically wound. In the case of a ~-;helically wound reinforcement, one strand is helically wound ; on the core tube in one direction and another strand is helically wound over the first strand in the opposite direction and the two strands together comprise one layer of reinforcement material. The first reinforcing layer may or may not be bonded to the core tube and the second reinforsing layer may or may not be bonded to the first reinforcing layer and/or the sheath. However, in the preferred embodiment of the invention, there is no bon~
between the first and second reinforcing layers, but there is a bond between the second layer and the sheath. Any suitable method may be used for bonding the various layers together such as epoxy adhesives, polyurethane adhesives, or solvents.
The Kevlar yarn imparts greater radial and axial dimensional stability to the hose when subjected to fluid pressure than hoses having reinforcement layers of Nylon 6/6, -Dacron, rayon and other non-metallic fibrous materials heretofore used because it has a substantially higher modulus and a lower elastic elongation value than those other materials.
The lower elastic elongation, however, still permits sufficient expansion of the first reinforcement layer to allow some sharing of the load by the second reinforcement layer, but the expansion is less than that of Nylon 6/6, Dacron, rayon, or the like so that hydraulic system sluggishness or sponginess is minimi~ed.
107l~308 On the other hand, because the elastic elongation of Kevlar i5 substantially greater than that of steel wire, the expansion in volume under fluid pressure of the hose -having a Kevlar reinforcement layer is greater than that of a hose having a steel wire reinforcement layer. Thus, `~-a hose using Kevlar as the reinforcement material cushions or dissipates hydraulic shocks to a greater degree than a hose with steel reinforcement.
Although the second reinforcing layer, which is of material other than Kevlar, shares part of the load, it also functions as a filler to increase the wall thickness of the hose so that the hose can be assembled to standard co~plings. (Use of a second layer of Xevlar to increase the wall tllickness so that the hose can be assembled to standard couplings is not economical because, as previously mentioned, Kevlar is more expensive than ~ylon 6/6, Dacron, rayon, or the like.) In addition, the second reinforcing layer prevents crushing of the Kevlar layer when the coupling is attached since it is not as brittle as Kevlar. Also, by reinforcing the hose structure, the second layer also minimizes hose kinking. It should be noted that the hose can be constructed with or without an outer sheath. When constructed without an outer sheath, the hose is very flexible since the material used for the second reinforcing layer is more flexible than that used for the outer sheath.
Variations of the present invention will be apparent to those having ordinary skill in the art and the invention -~
is limited only by the spirit and scope of the following claims.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A high burst strength flexible composite reinforced hose for conveying fluids under pressure compri-sing a synthetic polymeric core tube, a first layer of fibrous reinforcing material disposed adjacent the core tube having synthetic filaments having a tenacity at room tempera-ture of from 15 to about 25 grams per denier, and another layer of reinforcing material over the first layer and formed of composite fibers having a tenacity at room temperature less than that of said first layer.
2. The synthetic hose of Claim 1, in which there is a synthetic polymeric sheath covering the reinforcing material.
3. The composite hose of Claim 2, wherein the layer of reinforcing material adjacent to the core tube is braided aromatic polyamide filament having a tenacity at room temperature of 25 grams per denier and the other layer is braided and has filaments of poly (ethylene terephthalate) ester or nylon.
4. The composite hose of Claim 2, having a core tube, a first layer of the said fibrous material adjacent to the core tube, a braided layer of poly (ethylene terephtha-late) ester covering the said first layer and a polyurethane sheath.
5. The hose of Claim 2, wherein one or more layers of the said fibrous material are disposed about the core tube and said another reinforcing layer comprising poly (alkylene terephthalate) ester is disposed between the said fibrous material and the sheath.
6. The composite hose of Claim 2, wherein a plural-ity of layers of reinforcing fibers are disposed about the core tube and at least one of the layers is formed of composite fibers having a tenacity at room temperature of from about 7 to 11 grams per denier and another layer con-sists of fibers having a tenacity at room temperature of from 15 to 25 grams per denier and an elongation at break of about 2% to about 7%.
7. A high burst strength flexible composite hose for conveying fluids under pressure comprising a nylon core tube, and a fibrous reinforcing material which is disposed about the core tube and which comprises a braided layer of aromatic polyamide fibers having synthetic filaments having a tenacity at room temperature of from 15 to 25 grams per denier with an elongation at break of about 2% to about 7%, and a braided layer of poly (ethylene terephthalate) ester or nylon having a tenacity at room temperature less than that of said layer of aromatic polyamide fibers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA272,191A CA1078308A (en) | 1977-02-21 | 1977-02-21 | Hose construction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA272,191A CA1078308A (en) | 1977-02-21 | 1977-02-21 | Hose construction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078308A true CA1078308A (en) | 1980-05-27 |
Family
ID=4107973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA272,191A Expired CA1078308A (en) | 1977-02-21 | 1977-02-21 | Hose construction |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1078308A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5156785A (en) * | 1991-07-10 | 1992-10-20 | Cordis Corporation | Extruded tubing and catheters having increased rotational stiffness |
| US5248305A (en) * | 1989-08-04 | 1993-09-28 | Cordis Corporation | Extruded tubing and catheters having helical liquid crystal fibrils |
-
1977
- 1977-02-21 CA CA272,191A patent/CA1078308A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5248305A (en) * | 1989-08-04 | 1993-09-28 | Cordis Corporation | Extruded tubing and catheters having helical liquid crystal fibrils |
| US5156785A (en) * | 1991-07-10 | 1992-10-20 | Cordis Corporation | Extruded tubing and catheters having increased rotational stiffness |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |