EP3505776B1 - Device with components exposed to an aqueous fluid - Google Patents

Description

The invention relates to a device with at least two components, of which at least one component is at least partially exposed to a water-containing fluid, such as an HFC fluid, with the features in the preamble of claim 1.

According to the DE 10 2009 035 810 A1 Because of their flame-retardant properties, water-containing fluids can be used with advantage in hydraulic systems of military vehicles instead of the commonly used combustible hydraulic oils, such as mineral oils or synthetic oils. Military land, water and aircraft vehicles, in particular armored personnel carriers, battle tanks or team transport vehicles, have assemblies that define their essential functions via hydraulically actuated actuation systems, such as travel drives, drives for the respective weapon systems or opening and closing systems for armored doors and the like more. In the event of a bombardment of such vehicles in combat situations, damage to a hydraulic system which uses hydraulic fluid as the operating medium instead of hydraulic oil represents a reduced risk of fire. As stated in the above-mentioned document, hydraulic fluid which is flame-resistant can be advantageous an HFC fluid, which is commercially available. This fluid is biological degradable and fulfills the requirements of DIN EN ISO 12922 for flame-retardant liquids. However, the advantage of the safety gain achieved when these fluids are used is offset by the disadvantage that the hydraulic components in question are endangered by the lack of chemical compatibility with the water-containing fluids used as working media. The steels of the hydraulic components used in the prior art are either galvanized or coated with a zinc-nickel alloy. Both zinc and zinc-nickel alloys are not compatible with HFC fluid, which can lead to corrosion problems, for example.

The DE 43 33 894 C1 shows a method for resin treatment of metal surfaces. A metal part is zinc phosphated.

Other devices go out of the DE 39 24 246 A1 , of the DE 10 2013 223 216 A1 , of the CN 105 483 761 A and the EP 2 224 148 A1 forth.

In view of these problems, the object of the invention is to provide a device which, while maintaining the safety gain due to reduced fire risk, is characterized by chemical compatibility with water-containing fluids, in particular with HFC fluid.

According to claim 1, this object is achieved in a device of the type mentioned in that a component made of steel material that is in contact with both the fluid and the ambient air or nitrogen is chemically nickel-plated, that a component made of steel material which is completely in contact with the fluid, in particular is statically installed and has gaps or seals to the adjacent component, is zinc-phosphated that a component formed from steel material which is completely in contact with the fluid and at least in one operating state is completely flushed by the fluid is is left bare and that a component formed from aluminum material is anodized, at least one valve being installed as a component in a valve block as the further component, the valve block consisting of an aluminum material and being anodized on its outside facing the environment, whereby at Surfaces of the components that have an electrical potential difference between a gap and an outer gap area and use sealing elements for sealing the gap with respect to the outer gap area, in order to avoid crevice corrosion for the respective component, anodizing aluminum material, chemically nickel-plating steel material, the phosphorus content in of the coating has at least 10%, or use stainless steel, with surfaces of the components without an electrical potential difference between a gap and an outer gap area, between which no fluid exchange takes place, and with Nutver runs in the respective component, which seal two adjacent fluid spaces with the fluid against one another, and with at least one component which can only be moved to a limited extent or is arranged in a stationary manner to avoid crevice corrosion, for the respective valve component to anodize aluminum material and to use zinc-phosphated steel material, and in the case of surfaces of the components which have an electrical potential difference between the gap and the outer gap area, when fluid is exchanged between the gap and the outer gap area and with groove profiles in at least one component which seal two adjacent fluid spaces from one another, and with at least one movable component to avoid crevice corrosion for the the respective component is intended to leave the aluminum material bare and to leave the steel material bare.

The compatibility of the device with HFC fluid can not only be achieved by appropriate surface coatings of the components used for construction, but can also be achieved with existing devices can be realized by retrofitting, by making existing assemblies HFC-compatible, for example by zinc phosphating or by galvanizing galvanized components and re-nickel-plating.

For surfaces of the components that are completely flushed with the fluid, to avoid surface corrosion, it can be provided for the respective component to leave aluminum material bare or anodize, to leave steel material bare or to zinc-phosphate or nickel-plate and to use stainless steel material.

Furthermore, in order to avoid contact corrosion, the surface of the valve block as the further component should be chosen larger than the surfaces of the components used in the valve block in the area of their engagement in the valve block.

In the arrangements for corrosion protection coatings, the arrangement advantageously is such that the layer thickness μ m and zinc phosphated steel material about 5 of the anodized aluminum material is at least 10 μ m, the chemically nickel-plated steel material is at least 10 μ m.

Fig. 1

eine stark vereinfacht und lediglich skizzenhaft gezeichnete Darstellung zweier Komponenten, die in einem korrosionsgefährdeten Bereich I sowohl mit HFC-Fluid als auch mit Luft oder Stickstoff in Kontakt sind;

Fig. 2 und 2a

der Fig. 1 entsprechende Darstellungen eines korrosionsgefährdeten Bereichs II, in dem die Komponenten vollständig mit dem Fluid in Kontakt und statisch angeordnet sind, wobei die Komponenten gegenseitig abgedichtet sind bzw. durch einen engen Spalt voneinander getrennt sind;

Fig. 3

eine entsprechend vereinfachte Darstellung eines korrosionsgefährdeten Bereichs III, in dem eine dynamisch angeordnete Komponente vollständig mit dem Fluid in Kontakt ist und ein Flüssigkeitsaustausch durch Umspülen stattfindet;

Fig. 4

einen Vertikalschnitt eines Ventilblocks mit eingesetzten Ventilkomponenten gemäß einem Ausführungsbeispiel der erfindungsgemäßen Vorrichtung, wobei die Bereiche I bis III, die unterschiedlichen Arten von Korrosion ausgesetzt sind, kenntlich gemacht sind;

Fig. 5 und 6

Längsschnitte der durch ein Druckbegrenzungsventil bzw. ein Senkbremsventil gebildeten Ventilkomponenten des Ausführungsbeispiels, wobei die korrosionsgefährdeten Bereiche I der Fig. 1 kenntlich gemacht sind;

Fig. 7 und 8

den Fig. 5 und 6 entsprechende Längsschnitte, wobei die korrosionsgefährdeten Bereiche II von Fig. 2 kenntlich gemacht sind; und

Fig. 9 und 10

Teillängsschnitte der durch ein Rückschlagventil bzw. das Senkbremsventil gebildeten Ventilkomponenten des Ausführungsbeispiels, wobei die korrosionsgefährdeten Bereiche III von Fig. 3 kenntlich gemacht sind.

The invention is explained in detail below with reference to the drawing. Show it:

Fig. 1

a greatly simplified and merely sketchy representation of two components that are in a corrosion-prone area I in contact with both HFC fluid and air or nitrogen;

2 and 2a

of the Fig. 1 corresponding representations of a corrosion-prone area II, in which the components are completely in contact with the fluid and are arranged statically, wherein the components are mutually sealed or are separated from one another by a narrow gap;

Fig. 3

a correspondingly simplified illustration of a region III at risk of corrosion, in which a dynamically arranged component is completely in contact with the fluid and a liquid exchange takes place by rinsing;

Fig. 4

a vertical section of a valve block with inserted valve components according to an embodiment of the device according to the invention, the areas I to III, which are exposed to different types of corrosion, identified.

5 and 6

Longitudinal sections of the valve components of the exemplary embodiment formed by a pressure limiting valve or a lowering brake valve, the regions I of the Fig. 1 are identified;

7 and 8

the 5 and 6 Corresponding longitudinal sections, the areas II from Fig. 2 are identified; and

9 and 10

Partial longitudinal sections of the valve components of the exemplary embodiment formed by a check valve or the lowering brake valve, the regions III of Fig. 3 are identified.

The Fig. 1 illustrates a region labeled I at risk of corrosion between two components 2, 4, 6, 8, each consisting of steel or aluminum, sealed against one another by means of a sealing element 5 and on the sides separated by the seal once with a water-containing fluid, such as HFC fluid, and on the other side with a gaseous medium 3, such as air or nitrogen. The Fig. 2 and 2a show of the statically arranged components 2, 4, 6, 8 a region II at risk of corrosion, in which the components which are statically arranged are completely in contact with the fluid and are sealed off from one another or separated from one another by a gap 7, the gap width thereof is less than 0.5 mm. The Fig. 3 shows a correspondingly simplified representation of a corrosion-prone area III, in which a dynamic component 9, which, as indicated by double arrow 11, is movable, is arranged between the static components 2, 4, 6, 8 and is completely washed by the fluid that is in operation the device is replaced.

With regard to the 4 to 10 The invention is explained in more detail using an exemplary embodiment in which a valve block 2, which consists of an aluminum material, is provided as a component. The valve block 2 has a pressure relief valve 4 for controlling an associated hydraulic system, which is otherwise not shown, and which is provided in an armored military vehicle, for example, for actuating the drive mechanism, drive for weapon systems or opening and closing systems for armored doors and the like Lowering brake valve 6 and a check valve 8 as further valve components. The valves 4, 6 and 8 are formed by valves in a cartridge construction and are screwed into the valve block 2 with a housing part 10 or 12 or 14 formed from a steel material and are connected with their fluid connections in connection with fluid guides 16 located in the valve block 2, 18 and 20. To control the passage of their fluid connections, the valves 4, 6 and 8 each have spring-loaded valve bodies, which are designated 22 and 24 in the pressure relief valve 4. The valve body associated with the lowering brake valve 6 is denoted by 26 and the valve body of the check valve 8 is denoted by 28. Since the valves 4, 6 and 8, moreover, of commercially available Construction, there is no need to go into their further structural details.

In the Fig. 4 are the areas of I at risk of corrosion Fig. 1 identified. These areas are, for example, the pressure relief valve 4 or the lowering brake valve 6, in the 5 and 6 with dotted circular lines. These are surfaces which have an electrical potential difference between a gap and an outer gap region, sealing elements 30, 32 and 34 being arranged which form the seal between the gap and the outer gap region. To reduce corrosion in these areas, aluminum materials must be anodized, steel materials chemically nickel-plated, the phosphorus content in the coating being at least 10%, or stainless steel must be used.

In Fig. 4 are also areas II at risk of corrosion Fig. 2 and 2a identified. These areas are, for example, as far as the pressure relief valve 4 and the lowering brake valve 6 are concerned 7 and 8 with dotted circular lines. The area II differs from the area I in that there is no potential difference between the gap and the outer gap area, components are completely in contact with the fluid and components are not or only slightly moved relative to one another, with no fluid exchange taking place in the gap 7. Adjacent fluid spaces are sealed off from one another by sealing elements 36 or 38 and 40. To reduce corrosion in these areas, aluminum materials must be anodized, steel materials zinc phosphated or chemically nickel-plated, the phosphorus content in the coating being at least 10%, or stainless steel must be used.

In Fig. 4 are also areas III at risk of corrosion Fig. 3 identified. These areas are what, for example, the check valve 4 and the lowering brake valve 6, in the Fig. 9 or 10 with dash-dotted circular lines. Area III is corrosion-prone areas of the valve components that are completely in contact with the fluid, components (component 9) being moved towards one another and fluid exchange taking place in the gap that may be present. As in Fig. 9 specified, this is the area between the movable valve body 28 and the valve inner housing 42 in the check valve 8. In the lowering brake valve 6 ( Fig. 10 ), these are the gap areas between the valve inner housing 42 and the movable valve piston 26, which are sealed with the sealing elements 36, 38 and 40, and a gap region 44 near the screwing end of the inner housing 42 Leaving aluminum materials bright or anodizing them, as well as leaving respective steel materials bright, zinc phosphated or chemically nickel-plated, with the phosphorus content in the coating being at least 10%, or stainless steel must be used.

For the corrosion-reducing coatings, the layer thicknesses of the anodized aluminum material can advantageously be at least 10 μm and in the case of chemically nickel-plated steel material, the phosphorus content in the coating being at least 10%, being at least 10 μm .

Claims (4)

1. Device with at least two components (2, 4, 6, 8), of which at least one component (2, 4, 6, 8) is at least partially exposed to an aqueous fluid, such as an HFC-Fluid, and can be fixed in a housing (2) as an additional component, wherein

   - one component (4, 6, 8) made from steel material, which is in contact both with the fluid and with the ambient air or nitrogen (Fig. 1), is chemically nickel-plated;

   - one component (2, 4, 6, 8) made from steel material, which is completely in contact with the fluid, is in particular installed statically and comprises gaps (7), particularly measuring < 0.5 mm, or seals (5) between it and the adjacent component (4, 6), is coated with zinc phosphate;

   - one component (4, 6) made from steel material, which is completely in contact with the fluid and is completely surrounded by the fluid in an operating state, is left uncoated; and

   - one component (2) made from aluminium material is anodised,

   characterised
   in that at least one valve (4, 6, 8) is installed as a component in a valve block (2) as the additional component;
   in that the valve block (2) is made from an aluminium material and is anodised on its outer side facing the environment;
   in that, on surfaces of the components (2, 4, 6, 8) having an electrical potential difference between a gap and an outer gap region and using sealing elements (30, 32, 34, 36, 38, 40) to seal the gap from the outer gap region, the following measures are proposed to avoid crevice corrosion for the respective component (2, 4, 6, 8):

   - anodising aluminium material,

   - chemically nickel-plating steel material, the phosphorus content in the coating amounting to at least 10%, or

   - using stainless steel;

   in that, on surfaces of the components (2, 4, 6, 8) that do not have an electrical potential difference between a gap and an outer gap region, between which there is no fluid exchange, and with groove runs in the respective component (2, 4, 6, 8), which seal two adjacent fluid chambers with the fluid against one another, and with at least one component (2, 4, 6, 8) which is arranged such that it is stationary or has only limited mobility, the following measures are proposed to avoid crevice corrosion for the respective valve component (2, 4, 6, 8):

   - anodising aluminium material and

   - using steel material with a zinc phosphate coating; and

   in that, on surfaces of the components (4, 6, 8) having an electrical potential difference between gap and outer gap region, when fluid is exchanged between the gap and the outer region and with groove runs in at least one component (4, 6, 8), which seal two adjacent fluid chambers against one another, and with at least one movable component (22, 24, 26, 28), the following measures are proposed to avoid crevice corrosion for the respective component (4, 6, 8):

   - leaving the aluminium material uncoated and

   - leaving the steel material uncoated.
2. Device according to claim 1, characterised in that, on surfaces of the components (2, 4, 6, 8) that are completely surrounded by the fluid, the following measures are proposed to avoid surface corrosion for the respective component (2, 4, 6, 8):

   - leaving the aluminium material uncoated or anodising the aluminium material, and

   - leaving the steel material uncoated, or coating with zinc phosphate or nickel plating;

   - using stainless steel material.
3. Valve device according to either claim 1 or claim 2, characterised in that, to prevent contact corrosion, the surface area of the valve block (2) as the additional component is selected such that it is larger than the surface areas of the components (4, 6, 8) used in the valve block (2) in the region where they engage in the valve block (2).
4. Device according to any one of the preceding claims, characterised in that the coating thickness

   - of the anodised aluminium material is at least 10 µm;

   - of the chemically nickel-plated steel material is at least 10 µm; and

   - of the zinc phosphate-coated steel material is approximately 5 µm.

Images