WO2010140913A1 - Bouteille métallo-composite à haute pression - Google Patents

Bouteille métallo-composite à haute pression Download PDF

Info

Publication number
WO2010140913A1
WO2010140913A1 PCT/RU2009/000274 RU2009000274W WO2010140913A1 WO 2010140913 A1 WO2010140913 A1 WO 2010140913A1 RU 2009000274 W RU2009000274 W RU 2009000274W WO 2010140913 A1 WO2010140913 A1 WO 2010140913A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
modulus
layers
group
information carrier
Prior art date
Application number
PCT/RU2009/000274
Other languages
English (en)
Russian (ru)
Inventor
Сергей Владимирович ЛУКЬЯНЕЦ
Николай Григорьевич МОРОЗ
Игорь Константинович ЛЕБЕДЕВ
Original Assignee
Lukyanets Sergei Vladimirovich
Moroz Nikolai Grigorievich
Lebedev Igor Konstantinovich
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Lukyanets Sergei Vladimirovich, Moroz Nikolai Grigorievich, Lebedev Igor Konstantinovich filed Critical Lukyanets Sergei Vladimirovich
Priority to PCT/RU2009/000274 priority Critical patent/WO2010140913A1/fr
Publication of WO2010140913A1 publication Critical patent/WO2010140913A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
    • F17C1/02—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge involving reinforcing arrangements
    • F17C1/04—Protecting sheathings
    • F17C1/06—Protecting sheathings built-up from wound-on bands or filamentary material, e.g. wires
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C1/00—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge
    • F17C1/16—Pressure vessels, e.g. gas cylinder, gas tank, replaceable cartridge constructed of plastics materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/01—Shape
    • F17C2201/0104—Shape cylindrical
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0602—Wall structures; Special features thereof
    • F17C2203/0604—Liners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0602—Wall structures; Special features thereof
    • F17C2203/0607—Coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0636—Metals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0658—Synthetics
    • F17C2203/066—Plastics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0658—Synthetics
    • F17C2203/0663—Synthetics in form of fibers or filaments
    • F17C2203/0665—Synthetics in form of fibers or filaments radially wound
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0658—Synthetics
    • F17C2203/0663—Synthetics in form of fibers or filaments
    • F17C2203/067—Synthetics in form of fibers or filaments helically wound
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0658—Synthetics
    • F17C2203/0663—Synthetics in form of fibers or filaments
    • F17C2203/0673—Polymers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2205/00—Vessel construction, in particular mounting arrangements, attachments or identifications means
    • F17C2205/05—Vessel or content identifications, e.g. labels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
    • F17C2223/035—High pressure (>10 bar)

Definitions

  • the invention relates to the field of gas equipment, namely to metal composite pressure cylinders used, in particular, in portable oxygen breathing apparatus for climbers, rescuers, in portable products of cryogenic and fire fighting equipment, gas supply systems and other industries.
  • metal-composite high-pressure cylinders contain an internal thin-walled metal hermetic shell - a liner and an external power shell of composite material formed by winding high-modulus fiber bundles (e.g. carbon fiber) impregnated with a binder on the surface of the liner.
  • high-modulus fiber bundles e.g. carbon fiber
  • a high-pressure cylinder is known containing an external power shell made of composite material and an internal thin-walled sealed liner, and a label-passport of the cylinder is installed between the inner and outer layers of the power shell (see RU 69610 Ul, December 27, 2007).
  • the known solutions do not allow to solve the problem of absorption and reflection of light forming an image in the visible wavelength range, and thereby show that when using composite materials in the construction of a cylinder with a high absorption coefficient of light waves, the problem of qualitative communication of design information is not solved.
  • the technical result of the invention is the creation of a metal composite pressure cylinder, the design of which allows you to qualitatively apply information and save it throughout the life of the balloon with increased sharpness and contrast of its image while maintaining a low specific material consumption of the balloon.
  • the high-pressure cylinder contains a thin-walled closed sealing metal liner and an external power shell made of composite material formed by a combination groups of layers of high-modulus and low-modulus threads of reinforcing materials oriented in spiral and circumferential directions, while on the part of the cylindrical surface of the power shell in the structure of its wall, a cylindrical information carrier consisting of a layer of reflective material is installed between the group of layers of high-modulus and the group of layers of low-modulus threads of reinforcing materials, layer of light-absorbing material and the identification information frame located between them, and located on top of
  • a group of layers of low-modulus reinforcing threads impregnated with a polymeric binder forms a material with a higher optical density than the optical density of the carrier material and is additionally coated with an adhesive layer of an optically transparent paint coating.
  • glass fibers with a linear density of not higher than 600 tex can be used as a group of layers of low-modulus reinforcing threads.
  • the storage medium may further comprise a barrier or binder layer of material located between the inner layer of low-modulus reinforcing threads impregnated with a polymer binder and a two-component layer of reflective material.
  • the identification information frame of the information carrier may be made of paper.
  • the identification information frame of the information carrier can at least partially be made of polymer fibers, preferably polyamide fibers.
  • a luminescent coating layer containing an identification agent sensitive to UV light can be applied to the information frame of the information carrier.
  • Inorganic pigments reflecting infrared radiation can be applied to the information frame of the information carrier.
  • the information frame of the information carrier may include an optical brightener or a contrasting identification agent and a binder.
  • a polymer composition may be used, including an epoxy diane resin, a hardener and a filler in the form of titanium dioxide, zinc oxide or zinc oxide.
  • the layer of light-absorbing material may have an absorption coefficient of 10 5 / cm.
  • the storage medium may be provided with at least one security feature.
  • the security feature that the information carrier is provided with is selected from the group consisting of print, diffraction structures, metal coating, phosphors, thin-layer elements, liquid crystals, magnetic pigments, thermochromic substances, photochromic substances and dyes.
  • FIG. 1 shows a general view of a composite pressure balloon.
  • FIG. 2 is a schematic model of the wall of a cylinder with a storage medium.
  • the cylinder design contains the first 1 (layer of low-modulus reinforcing threads impregnated with a polymeric binder) and the second 2 (layer of high-modulus reinforcing threads of a power sheath impregnated with a polymeric binder) optical layers, each of which has an outer surface and an opposite inner surface, the profile of which is made in the form of an array of blurry pyramidal prisms.
  • the third and fourth layers have a low, and the first, second layers have a high refractive index.
  • the third layer is made of a material with an anomalous dispersion of the refractive index.
  • the design of the cylinder operates as follows. A ray of external light enters the first layer 1, which has a wavy surface close to the prismatic surface of a pyramidal shape. Due to the resonance diffraction effect, only a beam with a fixed angle of incidence and a given wavelength passes through a zigzag structure formed by the inner surfaces of the first and second layers, as well as the third and fourth thin optical layers, into the second layer with a prismatic outer surface.
  • This filtered light is reflected by the reflective layer 4 and passes back through the layered structure in the direction of the observer.
  • a layer of optically transparent coat 5 with a high purity of the outer surface is applied to the outer surface of the layer 1.
  • Light with different wavelengths and other angles of incidence is reflected from the zigzag multilayer structure and is scattered in different directions.
  • the multilayer structure of the claimed design functions as a polarizing filter, that is, only one linear state of light is passed through the structure.
  • Optimization of the transmission of transmitted light can be carried out by changing the thickness of the layers and the refractive indices of the used layer materials.
  • glass fibers with a linear density of not higher than 600 tex as a group of layers of low-modulus reinforcing yarns.
  • This material, impregnated with a polymer binder forms a layer 1 with surfaces in the form of blurry prisms and allows you to vary their sizes due to changes in the technological parameters of the winding.
  • the thickness of the threads, the width of the wound tape from these threads, the winding pattern, the formation of various variants of the wavy surface is possible.
  • a luminescent coating layer containing an identification agent sensitive to UV light or inorganic pigments reflecting infrared radiation for high-quality transmission and storage of information on the identification information frame.
  • an optical brightener or a contrasting identification agent and a binder into the information frame of the information medium, and also use a polymer composition including an epoxy diane resin, a hardener, and a filler in the form of titanium dioxide and zinc oxide as a material of the light-absorbing layer. or zinc oxide.
  • security features can be selected from the group including print, diffraction structures, metal coating, phosphors, thin-layer elements, liquid crystals, magnetic pigments, thermochromic substances, photochromic substances and dyes.
  • the invention is used in the field of gas equipment, namely in metal composite high-pressure cylinders used, in particular, in portable oxygen breathing apparatus of climbers, rescuers, in portable products of cryogenic and fire fighting equipment, gas supply systems and other industries.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

Le but de la présente invention est de pouvoir appliquer avec qualité des informations et de les conserver pendant toute la durée d'exploitation de la bouteille avec une plus grande définition et un meilleur contraste. Ce résultat peut être obtenu grâce à une bouteille à haute pression qui comprend une enveloppe métallique d'étanchéité fermée et à paroi fine et une enveloppe de force externe faite d'un matériau composite et formée par une combinaison de groupes de couches comprenant des fils à modules élevés et faibles de matériaux de renfort qui sont orientés dans des directions de spirale et de boucle. Un support d'informations cylindrique est monté sur une partie de la surface cylindrique de l'enveloppe de force dans la structure de sa paroi entre le groupe de couches de fils à module élevé et le groupe de couches de fils à faible module en matériaux de renfort, lequel support comprend une couche d'un matériau réfléchissant la lumière, un couche d'un matériau absorbant la lumière et une structure informative et d'identification disposée entre elles, tandis qu'est disposé sur le support d'informations un groupe de couches de fils de renfort à faible module imprégnés d'un liant polymère, lequel groupe forme un matériau ayant une densité optique supérieure à celle du matériau du support, et est en outre recouvert d'une couche adhésive d'un revêtement de type laque optiquement transparent.
PCT/RU2009/000274 2009-06-01 2009-06-01 Bouteille métallo-composite à haute pression WO2010140913A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/RU2009/000274 WO2010140913A1 (fr) 2009-06-01 2009-06-01 Bouteille métallo-composite à haute pression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/RU2009/000274 WO2010140913A1 (fr) 2009-06-01 2009-06-01 Bouteille métallo-composite à haute pression

Publications (1)

Publication Number Publication Date
WO2010140913A1 true WO2010140913A1 (fr) 2010-12-09

Family

ID=43297905

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/RU2009/000274 WO2010140913A1 (fr) 2009-06-01 2009-06-01 Bouteille métallo-composite à haute pression

Country Status (1)

Country Link
WO (1) WO2010140913A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010033623A1 (de) * 2010-08-06 2012-02-09 Daimler Ag Vorrichtung zum Speichern eines Mediums und Verfahren zum Herstellen einer solchen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4589562A (en) * 1981-05-04 1986-05-20 Fawley Norman Structures reinforced by a composite material
SU1749859A1 (ru) * 1988-08-30 1992-07-23 Проектно-Конструкторское Бюро Министерства Приборостроения, Средств Автоматизации И Систем Управления Устройство дл калибровани стрелочных электроизмерительных приборов
FR2850361A1 (fr) * 2003-01-24 2004-07-30 Henri Becu Dispositif pour visualiser les blessures, les impacts, les coups ou les chocs de tous ordres recus par une bouteille composite ou un reservoir composite
RU69610U1 (ru) * 2007-08-23 2007-12-27 Общество с ограниченной ответственностью научно-производственная фирма "Реал-Шторм" Композитный баллон высокого давления

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4589562A (en) * 1981-05-04 1986-05-20 Fawley Norman Structures reinforced by a composite material
SU1749859A1 (ru) * 1988-08-30 1992-07-23 Проектно-Конструкторское Бюро Министерства Приборостроения, Средств Автоматизации И Систем Управления Устройство дл калибровани стрелочных электроизмерительных приборов
FR2850361A1 (fr) * 2003-01-24 2004-07-30 Henri Becu Dispositif pour visualiser les blessures, les impacts, les coups ou les chocs de tous ordres recus par une bouteille composite ou un reservoir composite
RU69610U1 (ru) * 2007-08-23 2007-12-27 Общество с ограниченной ответственностью научно-производственная фирма "Реал-Шторм" Композитный баллон высокого давления

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010033623A1 (de) * 2010-08-06 2012-02-09 Daimler Ag Vorrichtung zum Speichern eines Mediums und Verfahren zum Herstellen einer solchen
DE102010033623B4 (de) * 2010-08-06 2012-02-16 Daimler Ag Vorrichtung zum Speichern eines Mediums und Verfahren zum Herstellen einer solchen

Similar Documents

Publication Publication Date Title
KR101512887B1 (ko) 광학체 및 그 제조 방법, 창재, 건구, 및 일사 차폐 장치
JP5508946B2 (ja) 光学体、窓材、建具、日射遮蔽装置、および建築物
KR101767680B1 (ko) 광학체 및 그 제조 방법, 일사 차폐 부재, 창재, 내장 부재 및 창호
JP6339053B2 (ja) 波長変換部材及びそれを備えたバックライトユニット、液晶表示装置
CN106133562B (zh) 波长转换片、背光单元以及荧光体用保护薄膜
US20170115437A1 (en) Optical device, sun screening apparatus, fitting, window material, and method of producing optical device
US20110310487A1 (en) Optical body, wall member, fitting, and solar shading device
EP2690472A2 (fr) Élément optique, matériau de fenêtre, ajustement et dispositif de protection d'isolation
JP2016122211A (ja) 波長変換シート用保護フィルム、波長変換シート及びバックライトユニット
WO2003050612A1 (fr) Ecran et procede de fabrication correspondant et systeme d'affichage d'image
SG177085A1 (en) Optical body, window member, fitting, and solar shading device
JP2012003025A (ja) 光学体、壁材、建具、日射遮蔽装置、および建築物
JP5662049B2 (ja) 光学体およびその製造方法、窓材、建具、ならびに日射遮蔽装置
JP5727718B2 (ja) 光学体およびその製造方法、窓材、建具、ならびに日射遮蔽装置
JP2011128512A (ja) 光学体およびその製造方法
KR20200066330A (ko) 형광체 보호 필름, 파장 변환 시트 및 발광 유닛
JP2016053742A (ja) 光学素子、日射遮蔽装置、建具、窓材および光学素子の製造方法
CN109641435B (zh) 荧光体保护膜、波长转换片及发光单元
JP2011164433A (ja) 光学体、窓材、建具、および日射遮蔽部材
US10734454B2 (en) Display stack including emissive display and color correction film
WO2010140913A1 (fr) Bouteille métallo-composite à haute pression
JP2019188721A (ja) 蛍光体保護フィルム及び波長変換シート並びに発光ユニット
RU103163U1 (ru) Металлокомпозитный баллон давления
WO2016051760A1 (fr) Élément de conversion de longueur d'onde, unité de rétroéclairage le comportant, et dispositif d'affichage à cristaux liquides
JP2004117480A (ja) 反射型スクリーン及びその製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09845595

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC

122 Ep: pct application non-entry in european phase

Ref document number: 09845595

Country of ref document: EP

Kind code of ref document: A1