RU14065U1 - METALLOPLASTIC HIGH PRESSURE CYLINDER (OPTIONS) - Google Patents

Abstract

Metal-plastic cylinder of a high pressure (options)

The metal-plastic high-pressure cylinder contains an internal liner made of seamless aluminum alloys and an external power shell of a high-strength fibrous polymer material - aramid fiber of the Armos type (CBM).

A relation is proposed for determining the thickness of the external power shell.

The power shell is an alternation of spiral and annular layers with a ratio of the thickness of the spiral layers to the thickness of the annular layers as 2/3.

3 n.p.

ESSAY

Description

Metal-plastic cylinder of a high pressure (options)

The utility model relates to the field of gas equipment, namely, to metal-plastic high-pressure cylinders (HP), used, in particular, in portable oxygen breathing apparatus of climbers, rescuers, in portable products of cryogenic and fire fighting equipment, where minimization of specific material consumption is essential ( d) a cylinder representing the ratio of the mass (M) of the cylinder to its capacity (V): d M / V,

Currently produced high-pressure metal-plastic cylinders (VD) contain an internal metal sealed liner and an external power plastic shell formed by winding on the surface of the liner a tow of high modulus fiber (for example, fiberglass, carbon fiber, aramid) impregnated with epoxy binders.

For example, a metal plastic cylinder of the IESIMech design is known, which contains a welded sealed steel liner and an external power plastic shell around the liner, such as a cocoon, made by longitudinally-transverse winding of fiberglass impregnated with epoxy binders (Automatic welding. No 9, 1995; B .E. Paton, MM Savitsky and others. Design and manufacturing technology of lightweight welded cylinders VD).

Also known is a metal-plastic cylinder VD containing a stamped-welded sealed steel liner and an external power

T O l E

Mlb: F17C 1/06

a plastic shell made of aramid fiber (RU, C1 2077682).

Welded and stamped-welded technologies make it possible to manufacture steel rails with sufficiently thin walls, thereby ensuring a relatively low specific material consumption (d) of the VD cylinder with a steel liner. However, welded and stamped-welded liners have a low resource in the number of loading cycles. which does not exceed several tens of hundreds.

Closest to the proposed technical solution is a metal-plastic cylinder VD, manufactured by SCI, USA, containing a seamless sealed aluminum liner and an external power plastic shell around the entire surface of the liner, made of either fiberglass or aramid fiber Kevlar brand (RU, C1 2077682),

Seamless liners provide a significantly higher resource in the number of loading cycles (more than 50,000) than welded or stamped - welded liners. At the same time, the use of aluminum alloys that are more ductile than steel makes it possible to fabricate by the method of deep drawing solid liners with sufficiently thin walls in order to provide a relatively low specific material consumption (d) of the VD cylinder.

In the above known constructions of metal-plastic cylinders VD, the minimization of specific material consumption is achieved by reducing the thickness of the walls of the metal liner. Moreover, with a decrease in the wall thickness of the metal liner, the bearing function

cylinder element are transferred from a metal liner to an external power plastic shell. The liner serves as a sealed cavity for gas, and the external plastic shell, formed by winding a tow of high modulus fiber (fiberglass, carbon fiber, aramid) impregnated with epoxy binders, almost completely accepts the power loads. Accordingly, the strength characteristics of the VD cylinders are provided to a greater extent by the plastic shell.

In this regard, the question arises of choosing the type of high-modulus fiber with high strength and elastic characteristics in combination with low density to ensure high strength characteristics of VD cylinders without increasing specific material consumption.

An analysis of the prior art does not reveal a preference for any particular type of known vysokomodulnogo fiber for the manufacture of the power shell of cylinders VD

For example, fiberglass is used in cylinders of the IES-Imech design, aramid fiber is used in cylinders described in patent RU, С1 2077682, and both fiberglass and aramid fiber are used in SCI cylinders, USA.

The present utility model is based on the task of creating a metal-plastic cylinder VD, in which the plastic shell would be made of such fiber and have such structural parameters that would ensure the maximum possible strength characteristics of the cylinder with the minimum weight of the shell.

The problem is solved in that in a metal-plastic high-pressure cylinder containing an internal metal liner and an external power shell of high-strength fibrous polymeric material, according to the proposed technical solution, the power shell is made of aramid fiber of the Armos or CBM type.

The studies conducted by the authors showed the feasibility of using organic fibers in VD cylinders, which have high strength and elastic characteristics in combination with a lower density (1.44 - 1.45 g / cm) compared to carbon (1.7 1.8 g / cm) and glass (2.5 - 2.7 g / cm) with fibers.

In addition, a comprehensive analysis of the physicomechanical characteristics of organic fibers produced in Russia and abroad, as well as model composite materials based on them, showed that the use of aramid fibers is most appropriate (from the point of view of achieving HP in cylinders with a minimum weight of maximum tensile strength) fiber type Armos.

The use of aramid fibers of the Armos type for the external reinforcing shell allows metal liners to be made with a minimum wall thickness, limited only by the technological conditions for ensuring the rigidity of the liner when winding the power shell, in order to reduce the specific material consumption of the VD tanks.

It is advisable to carry out a metal liner seamless, from aluminum alloys.

to make by the method of deep drawing one-piece liners with sufficiently thin walls.

The problem is also solved by the fact that in a metal-plastic high-pressure container containing an internal liner made seamless of aluminum alloy and an external power shell of high-strength fibrous polymer material, according to the proposed technical solution, the power shell has a thickness defined by the ratio:

PP Rep. - OmaxAi hn

"1u,„. - „,, -I-J I- TTJ .., j: -.

in construction

PP p-prab. - estimated breaking pressure for the cylinder;

p - minimum safety margin according to the "Rules for the design and safe operation of vessels operating under pressure. PB 10-11596;

Rrab - maximum working pressure;

RCP - the radius of the middle surface of the cylindrical part of the container;

omaxAi STRENGTH of aluminum alloy;

Nl - the thickness of the cylindrical wall of the liner;

OB construct - strength of the power shell realized in the design of the balloon (average integral over the entire thickness of the winding);

The proposed formula for determining the thickness of the power shell is derived from the condition that the power shell perceives almost the entire load at operating pressure.

spiral and annular layers with a ratio of the thickness of the spiral layers to the thickness of the annular layers as 2/3.

The proposed structural performance of the power shell is determined by the authors based on the experience of testing the strength of metal-plastic cylinders BG 6.8 - 30.4 TU 2296-003-03455343-99, consisting of a seamless liner made of aluminum alloy and an organoplastic shell.

In the future, the best embodiment of the proposed utility model will be described in detail with reference to the drawings, in which:

FIG. 1 depicts a metal-plastic cylinder VD, longitudinal

incision;

Figure 2 - scheme of reinforcing the power shell of aramid

Armos material.

High pressure metal-plastic cylinder | VD) contains an internal metal sealed liner 1 (Fig. 1) and a power shell 2, such as a “cocoon, made of high-strength fibrous polymer material, covering the entire outer surface of the liner 1.

The liner 1 is made seamless, from an aluminum alloy, for example, by deep rotational drawing. In order to minimize the specific material consumption (d) of the balloon, the wall thickness of the liner 1 is chosen as minimal as possible from the condition of ensuring the rigidity of the liner 1 when winding the power shell 2.

The power shell 2 is made by winding onto the liner 1 a high-strength fibrous polymer material impregnated with polymer binders, for example, epoxy resin.

Aramid fiber of the type “Armos.

Studies by the authors have shown the feasibility of using organic fibers compared to carbon and glass. This is due to the high strength and elastic characteristics of organic fibers in combination with a lower density (1.44 - 1.45 g / cm) compared to carbon (1.7 - 1.8 g / cm) and glass (2.5 - 2.7 g / cm) fibers.

Organic fibers developed in Russia can be divided into two main classes. These are aramid fibers and polyimide fibers. Aramid fibers include: Armos, CBM, Terlon. To polyimide fibers: Arimid VM, ArimidT.

The following grades of aramid fibers were best known abroad: Kevlar-49 (DuPont, USA) and Twaron-2200 (Akzo Nobel, Netherlands).

Table 1 shows the comparative physical and mechanical characteristics of aramid and polyimide fibers according to the results of tests on tensile testing machines of the type 1958U-10-1, Textima-1505 (Zwick) and UMIV-Zm. Designations adopted 0 table: d, micron tensile strength of a monofilament based on 20mm, MPa; apv - tensile strength of a fiber bundle based on 120mm, MPa; Ev - Young's modulus for monofilament tension, GPa; 8p, is the tensile deformation of the monofilament,%; Tr, is the fiber softening temperature, determined from the creep tests of the fibers when scanning at a temperature of 5C / min, C;

Table analysis 1 shows that polyimide fibers, despite their rather high heat-resistant properties (Tr), are inferior to aramid fibers in strength and elastic characteristics and, therefore, cannot compete with aramid fibers when used in HP cylinders. In addition, the use of VD cylinders at temperatures not exceeding 60 ° C makes it doubly impractical to use heat-resistant and, therefore, more expensive polyimide fibers. monofilament diameter, microns; a.

Of the aramid fibers, the most interesting are fibers of the Armos and CBM type, which, when combined with Terlon, Kevlar - 49, Twaron - 2200 fibers, have higher elastic and strength characteristics. The highest, but fairly close to CBM, values of tensile strength of the Armos fiber.

Table 2 shows the test results of composite materials based on organic fibers and a binder EDT-10. Composite materials were tested in the form of microplastics and ring samples with a diameter of 14 mm,

Physico-mechanical characteristics of composite materials based on organic B07i; ifflH and epo | Seed binder EDT-10.

Designations adopted in the table; Tsdv - shear stress between the fiber and the matrix, characterizing the degree of adhesive interaction of the organic fiber to EDT-10, MPa; amp - strength on

table 2

An analysis of Table 2 shows that Armos fibers realize their strength characteristics to the greatest extent in unidirectional composite materials and are somewhat inferior to CBM fibers.

The adhesion characteristics of aramid fibers to EDT-10 are approximately the same and are in the range of 20-30 MPa, for polyimide fibers these figures are higher.

Thus, the above complex analysis of the physicomechanical characteristics of organic fibers produced in Russia and abroad, as well as model composite materials based on them, shows that the most appropriate (from the point of view of achieving HP in cylinders with a minimum weight of maximum tensile strength) is the use in cylinders VD aramid fibers of the Armos type,

In FIG. 2 shows a reinforcement scheme of a power shell 2 of a fibrous polymeric material, such as Armos, including the alternation of spiral layers 3 and annular layers 4, shown by solid and dashed lines, respectively. In this case, the annular layers 4 are applied only to the cylindrical part of the surface of the liner 1, and the spiral layers 3 are applied to the entire surface of the liner 1, with the exception of the technological poles used to fix the liner 1 in the winding machine. Another structure of the winding of the power shell is also possible, which is selected by known methods depending on the operational characteristics of the HP cylinder: operating pressure, capacity and size of the cylinder.

The external power shell perform a thickness determined by the formula:

Rr Per. - C maxAl l

hj; .. rde:

in construction

PP prab - estimated destructive pressure for the cylinder;

p - the minimum safety margin according to PB 10-115-96;

Rrab - maximum working pressure;

RCP - the radius of the middle surface of the cylindrical part of the container;

omaxAi - STRENGTH of aluminum alloy;

Ll is the thickness of the cylindrical wall of the liner;

OB construct - strength of the shell

(average integral over the entire thickness of the winding);

The proposed formula for determining the thickness of the power shell is derived

from the condition that almost the entire load at operating pressure

perceives the power shell.

In this case, a power shell 2 of Armos type aramid fiber wound on a liner, including alternating spiral and annular layers, has a ratio of the thickness of the spiral layers to the thickness of the annular layers as 2/3.

The following are examples of specific design parameters of the VD cylinders made in accordance with the calculations using the proposed methods.

Example 1. The initial data for the cylinder VD, consisting of a seamless liner and an external power shell of a high-modulus aramid fiber, type,

Rrab 310 kgf / cm; n - 2.6; RR 806 kgf / cm; h - 0.254 cm. Ov 17125 kgf / cm; OVKONSTR. 11417 kgf / cm; Rep, 7.4 cm.

In accordance with the above relations, the force shell of the VD cylinder has the following design parameters: the total shell thickness hs 0.47 cm, while the thickness of the spiral layers of the shell hen. 0.19 cm and the thickness of the annular layers of the shell Ic 0.28 cm; Rounded should take hz 5 mm, hen. 2 mm, bk 2 mm Example 2. The initial data is the same, except for the outer diameter of the liner, equal to 301 mm, i.e. Rep 15.6 cm. In this case, the external shell has the following design parameters: hs 11 mm, hon, 4.5 mm, bk. 6.5 mm. In this case, the cylinder VD will have a specific material consumption equal to 0.6 and strength Rp 806 kgf / cmR.

From the description given above, it is clear that the considered implementation options allow modification1I, obvious to a person skilled in the art and not going beyond the essence of the proposed technical solution, which is determined by the utility model formula given below.

Claims (8)

1. Metal-plastic high-pressure cylinder, containing an inner liner and an external power shell of high-strength fibrous polymer material, characterized in that the power shell is made of aramid fiber of the Armos type (CBM).  2. The metal-plastic cylinder according to claim 1, characterized in that the liner is made seamless from aluminum alloy. 3. The metal-plastic cylinder of high pressure according to claim 2, characterized in that the power shell has a thickness determined by the ratio

where P _p = nP _slave - estimated destructive pressure for the cylinder;
n is the minimum safety margin according to PB 10-115-96;
P _slave - maximum working pressure;
R _cf is the radius of the middle surface of the cylindrical part of the container;
σ _maxAl is the tensile strength of an aluminum alloy;
h _l - the thickness of the cylindrical wall of the liner;
σ _{B construction} - the strength of the power shell realized in the design of the cylinder (the average integral over the entire thickness of the winding).  4. A high pressure metal-plastic cylinder according to claim 3, characterized in that the power shell is an alternation of spiral and annular layers with a ratio of the thickness of the spiral layers to the thickness of the annular layers as 2/3. 5. A metal-plastic high-pressure cylinder containing an internal liner made of seamless aluminum alloy and an external power shell of high-strength fibrous polymer material, characterized in that the power shell has a thickness determined by the ratio

where P _p = nP _slave - estimated destructive pressure for the cylinder;
n is the minimum safety margin according to PB 10-115-96;
P _slave - maximum working pressure;
R _cf is the radius of the middle surface of the cylindrical part of the container;
σ _maxAl is the tensile strength of an aluminum alloy;
h _l - the thickness of the cylindrical wall of the liner;
σ _{B construction} - the strength of the power shell realized in the design of the cylinder (the average integral over the entire thickness of the winding).  6. The high pressure metal-plastic cylinder according to claim 5, characterized in that the power shell is made of aramid fiber of the Armos type (CBM).  7. A metal-plastic high-pressure cylinder containing an internal liner made of seamless aluminum alloy and an external power shell of high-strength fibrous polymer material, characterized in that the power shell is an alternation of spiral and annular layers with respect to the thickness of the spiral layers to the thickness of the annular layers like 2/3. 8. The high pressure metal-plastic cylinder according to claim 7, characterized in that the power shell is made of aramid fiber of the Armos type (CBM).