Knowledge Center
From selection to assembly, from standards to maintenance: sourced technical guides on hose and connection technology.
215 guides
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What information is needed to select a hose?
Hose selection does not start with diameter and pressure alone. The fluid, temperature, application, dimensions, pressure/vacuum and end connections must be defined together. STAMPED is a reminder used to gather this in…
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How are inside diameter, outside diameter and overall length defined?
Inside diameter denotes the flow path, outside diameter the outer envelope, and overall length the assembly length between two defined references. These three dimensions cannot be used interchangeably. The cut length of…
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The difference between working, test and burst pressure
Working pressure refers to the service limit, test pressure to a defined test condition, and burst pressure to a separate strength test. The burst value is not a usable working pressure; no single universal ratio is ass…
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How are fluid and ambient temperature distinguished?
Fluid temperature is the condition the hose sees from the inside, and ambient temperature the condition it sees from the outside. Both are assessed in selection. Continuous operation, short-term peak, start-up and clean…
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Selection differences between suction and discharge applications
A discharge hose must be suitable for internal pressure, while a suction hose must be suitable for the external-internal pressure difference in the application. A high positive working pressure rating is not a guarantee…
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How to prepare a technical hose request form
A technical request form should make the unknowns in the application visible rather than ask for a product name. Fluid, temperature, pressure/vacuum, dimensions, movement and end connections are the core fields. Unknown…
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Guide to writing a hose assembly technical specification
A hose assembly specification defines the service conditions, the hose model or performance requirement, the A/B ends, overall length, orientations and acceptance documents in the same revision. The phrase 'hose with fi…
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Deriving a correct order definition from a sample hose
When preparing an order from a sample, visible dimensions must be separated from unknown service conditions. A sample is valuable for investigating product identity; however, on its own it does not show why it was selec…
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How to compare technical equivalence in quotations
Quotations are technically meaningful only if they are compared on the basis of the same service condition, the same assembly scope and the same acceptance terms. Placing a price per meter directly next to the price of …
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Questions to ask when an equivalent product is requested
In an equivalence assessment, the requirements to be met are fixed first, and then it is shown with which document the candidate product meets them. The same diameter, a similar appearance or the same standard family do…
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Why inch-to-millimeter conversion is not a nominal size match
One inch is exactly 25.4 millimeters. This length conversion is not an actual diameter match for a nominal hose size or a pipe thread. In an order, keep the numerical conversion separate from the product size definition.
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DN, dash and nominal hose sizes
DN, dash and inch expressions are not the same kind of dimension. DN is a nominal size designation; in many hose families, dash is used as a size code in sixteenths of an inch. However, the meaning of the code must be v…
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How to read the markings on a hose
The layline is the identification and property marking on the outer surface of the hose. It may include manufacturer, series, nominal size, pressure or standard information; the content varies by product family. A photo…
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Measurement references for hose length and end connections
A length order must give a start and end reference along with the number. Fitting ends, sealing surfaces, elbow axes and bare hose ends can be different references. Unless the supplier and customer use the same referenc…
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Pressure units and the gauge vs. absolute pressure distinction
bar, MPa and psi are pressure units; the terms gauge and absolute indicate the reference of the pressure. Unit conversion does not change the reference. Especially in vacuum, gas and steam assessments, it must be clear …
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How does a wire braided hydraulic hose work?
In a wire braided hydraulic hose, the braided reinforcement around the inner tube helps carry the pressure load. Selection is not made by the number of braids alone; hose type, size, pressure, temperature, impulse condi…
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Differences between single and double wire braid
Single and double wire braid distinguish the construction of the reinforcement layers; on their own they do not indicate a specific working pressure. Comparisons should be made at the same size, and the products' actual…
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The selection logic for compact hydraulic hoses
Compact hydraulic hoses are designs that, in certain series, meet tighter installation requirements. For 'compact', the outside diameter, minimum bend radius and fitting system must be examined per product; it is not as…
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Using textile reinforced hydraulic lines
In textile reinforced hydraulic hoses, the load-bearing structure may consist of suitable fibers instead of metal wire. The pressures and fluids it is used with are determined per series. The term textile reinforcement …
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Selecting the outer cover of a hydraulic hose
The outer cover is selected for abrasion, weather, ozone, oil contact or other external effects. The fluid compatibility of the inner tube and the resistance of the outer cover are separate matters. A durable cover does…
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Where are spiral wire hydraulic hoses used?
In spiral wire hydraulic hoses, the reinforcement is formed with a wire arrangement different from braiding. This construction is seen in product families used in heavy hydraulic applications. For selection, the pressur…
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The constant pressure class approach for hydraulic hose
A constant pressure hose family means that the sizes within a defined product scope are offered according to a common working pressure class. It does not mean the pressure is kept constant inside the hose by itself. Tem…
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What does impulse performance mean?
Impulse resistance refers to performance under repeated pressure cycles. Passing a single hydrostatic test does not mean the same impulse life has been verified. A cycle count should only be compared together with the t…
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How to compare high flexibility claims
Flexibility is not measured by minimum bend radius alone. The force required to bend, limits for dynamic use, twisting behavior, weight and connection geometry also matter. The comparison should be made at the same size…
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When should braided and spiral construction be compared?
The choice between braided and spiral wire hose is made according to the pressure and impulse requirements of the application and the installation conditions. Neither construction is unconditionally superior to the othe…
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Selecting a hydraulic return line hose
A hydraulic return line should not be treated as equivalent to an ordinary liquid hose because of its seemingly low pressure. The fluid, temperature, flow rate, back pressures caused by filters and coolers, and transien…
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Vacuum resistance in a hydraulic suction line
A hydraulic suction hose must be suitable for the vacuum that will occur at the operating temperature and for the flow conditions. Being a high-pressure hose is not sufficient for suction. Collapse resistance, inside di…
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Checklist for water-based hydraulic fluids
With water-based hydraulic fluids, hose selection cannot be made based only on the phrase 'hydraulic oil compatible'. The fluid class, actual composition, temperature and manufacturer approval are decisive. The same hos…
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Compatibility in high-temperature hydraulic lines
In high-temperature hydraulic service, the conditions to be met jointly by the hose, fittings and seals must be defined. It is not assumed that the highest temperature and the highest pressure in the catalog apply at th…
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Using hydraulic hose in cold environments
For a hydraulic hose to be used at low temperature, not only the storage temperature but also cold bending and the operating condition must be verified. The behavior of the hose, seals and fluid are assessed together. F…
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