Knowledge Center
From selection to assembly, from standards to maintenance: sourced technical guides on hose and connection technology.
215 guides
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How does a Camlock coupling work and where are its limits?
A Camlock or cam and groove coupling is a quick-connect family in which an adapter and a coupler are joined by means of arms. The correct size, seal, material and service limit are selected together; the fact that the c…
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Specifying types of cam and groove couplings in orders
Camlock type letters describe whether the coupling is an adapter or a coupler and whether the other end is threaded or has a hose shank. In addition to the type letter, the size, thread standard, material, seal and appl…
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Flat-face hydraulic quick couplings
A flat-face hydraulic quick coupling uses an interface that makes the connection face easier to clean. A low-spillage objective or a flat face does not mean that every model can be connected and disconnected under press…
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Poppet-type hydraulic quick couplings
In valved quick couplings, the internal valves are part of fluid control when disconnected. The presence of a valve is not a guarantee of zero spillage, zero air inclusion or connection under pressure; the coupling seri…
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Selection questions for dry disconnect couplings
A dry disconnect coupling is a design that manages the connection and valve movement together in order to limit fluid release during disconnection. Dry disconnection is not the same function as a safety breakaway coupli…
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Identifying the series of hydraulic flange connections
In a hydraulic four-bolt flange, the hose flange head, clamp parts, O-ring, port face and bolts work together. Merely seeing the flange head diameter or four holes does not mean that the correct series and assembly have…
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How to distinguish Code 61 from Code 62
Code 61 and Code 62 are different series designations for hydraulic flange connections; the same nominal hose size does not show that they are interchangeable. The flange head, hole pattern, bolts, seal and the product'…
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Why PN and Class flange designations are not the same
PN and Class are designations used in different flange classification systems; Class 150 does not directly mean 150 psi. The permissible pressure is determined from the relevant standard table together with material and…
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Dimensional references for hygienic clamp connections
In a hygienic clamp connection, the clamp outside diameter, tube diameter and flow bore are different dimensions. For a correct match, the connection standard, series, ferrule geometry, gasket and clamp must be defined …
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Order information for DIN hygienic fittings
In a DIN 11851 type hygienic fitting, the nut, connection ends and seal together form a system. Ordering only by the round nut or the nominal diameter is not sufficient for correct geometry and cleanability.
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Hose clamp types and their limits of use
Clamp selection is not just a matter of finding a band that fits the hose outside diameter. The hose construction, hose shank, pressure or vacuum, temperature, material and the manufacturer's assembly method must be eva…
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Band and diameter range of worm drive clamps
With a worm drive clamp, selection starts with the outside diameter of the hose on the fitting falling within the appropriate clamping range; however, band construction, material, position and the manufacturer's torque …
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Selection checklist for heavy-duty clamps
A heavy-duty clamp may offer a different clamping and housing construction for certain applications; however, its name does not show that it can be used on all high-pressure or steam hoses. The combination verified with…
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What is a spring-tension clamp used for?
A spring-loaded or constant-tension clamp may be designed to accommodate diameter changes in the assembly within a certain working range. This feature does not resolve all causes of loosening; the correct diameter, spri…
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Why is clamp tightening torque product-specific?
Clamp or fitting torque depends on the product code, size, material and assembly condition concerned. A safe torque should not be determined by looking at the screw diameter or by taking a value from another brand's tab…
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How should NBR, EPDM and SBR be compared?
NBR, EPDM and SBR are different elastomer families. NBR may be investigated for oil contact, EPDM for outdoor exposure and certain water applications, and SBR for general mechanical and abrasion requirements; however, t…
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FKM, IIR and CR material families
FKM, IIR and CR denote different elastomer families; they cannot be used as if they were a single 'special rubber' class. Selection must be based on permeation, weathering, deformation and actual compound data in additi…
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Selection questions for UHMWPE and XLPE inner tubes
UHMWPE and XLPE are related to polyethylene but are different structural designations. UHMWPE refers to ultra-high molecular weight and XLPE to a cross-linked structure; no common pressure, temperature or chemical compa…
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Why a material name alone is not compatibility approval
The general chemical resistance of a material is not approval for the use of all hoses or fittings that contain that material. Compatibility is verified together with the actual product, fluid mixture, temperature, conc…
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Seal material, hardness and compound designation
Seal hardness and seal material are not the same information. Different hardnesses and formulations within the same elastomer family can behave differently; the correct seal is selected together with the connection geom…
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How does the stainless steel grade affect fitting selection?
Stainless steel is a family of materials; 304, 316 and other grades do not behave the same in every environment. Fluid, chlorides, temperature, stress and connection geometry are evaluated together; the word 'stainless'…
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Surface coatings on carbon steel fittings
On a coated carbon steel fitting, the coating is part of the resistance to the external environment; it does not replace the base material or the connection geometry. The coating type and test conditions must be evaluat…
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Fluid compatibility of brass fittings
When selecting a brass fitting, not only machinability or price but also the alloy, fluid, temperature and the documentation requirements of the application are evaluated. The name 'brass' is not a blanket declaration o…
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Corrosion when dissimilar metals are used together
Galvanic corrosion is a corrosion mechanism that can occur between dissimilar metals in electrical contact in a suitable electrolyte. Knowing only the names of the two metals is not enough to decide definitively whether…
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Protecting connections in salty and humid environments
In salty and humid environments, compatibility with the internal fluid is not sufficient for hose connections. External corrosion, moisture accumulation in crevices, dissimilar metal contacts and areas hidden under prot…
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Conductive, antistatic and insulating hoses: the differences
The terms conductive, antistatic and insulating do not mean the same thing. It should be stated which electrical property is defined by which test method and product standard; a single resistance range should not be ass…
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What does end-to-end electrical continuity mean?
End-to-end electrical continuity is evaluated between defined connection points on the completed hose assembly. Information given about the hose body or the metal reinforcement does not replace the measurement result fo…
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Is a metal helix proof of grounding?
A metal helix or braid is not in itself a verified grounding connection. How the metal contacts the ends, the continuity path and the application criteria must be clearly defined and measured; visible wire is not suffic…
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What information does an electrical resistance measurement record need?
An electrical resistance measurement record should contain the assembly identification, measurement points, method, instrument, conditions, result and acceptance source. An ohm value or a 'passed' statement alone is not…
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Gathering information for hose selection in explosive atmospheres
Hose selection for an explosive atmosphere is not completed simply by asking for an antistatic product. The gas or dust hazard of the area, process conditions, electrical requirements, hot surfaces and the use of the en…
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