Knowledge Center
From selection to assembly, from standards to maintenance: sourced technical guides on hose and connection technology.
215 guides
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Construction of corrugated metal hoses
A corrugated metal hose is a type of hose that derives its flexibility from the corrugated structure of a metal tube wall. Fluid contact, pressure, temperature, motion and end fittings are evaluated together; the name s…
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Braid and pressure in metal hoses
The outer braid of a metal hose is part of the design for carrying the loads that arise under pressure. The number of braid layers does not on its own determine the pressure rating; the body, diameter, material, tempera…
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Vibration and fatigue in metal hoses
The vibration resistance of a metal hose cannot be demonstrated merely by passing a static pressure test. The direction, amplitude and frequency of motion, the live length and the stresses near the fitting are evaluated…
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Weld and document checks on metal hose ends
In a welded metal hose, the material document, weld fabrication and the finished assembly test are different pieces of evidence. A single certificate does not automatically cover all of these; the required documents mus…
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Static and dynamic installation of metal hoses
The static minimum bend radius is not automatically valid for dynamic use. In a dynamic application, the radius, live length and routing for the product's motion condition must be used; static and dynamic values are kep…
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Smooth-bore and convoluted PTFE hose
The choice between smooth-bore and convoluted PTFE hose is not made on the basis of flexibility alone. Flow and cleaning requirements, bending space, permeation, pressure and fitting construction are evaluated together;…
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The concept of static-dissipative PTFE hose
Antistatic PTFE is not considered to have the same electrical properties as an ordinary PTFE inner tube. The required electrical behavior must be clearly defined in the product code and manufacturer data, and verified t…
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Permeation and gas service in PTFE hose
Permeation is a behavior related to the ability of a fluid to pass through the hose material; it is not the same as a visible hole or a fitting leak. In gas transfer, the inner tube, gas type, pressure, temperature and …
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Evaluating temperature and pressure together in PTFE hose
The pressure and temperature limits of a PTFE assembly cannot be derived solely from the general properties of the PTFE polymer. The inner tube, reinforcement, end fitting, seal and the manufacturer's temperature-depend…
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Technical questions in fluoropolymer hose selection
For fluoropolymer hose selection, the process questions must be answered first: which fluid, which temperature, which pressure, what cleaning and what kind of motion? Choosing PTFE or another material name does not on i…
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Layered construction of composite hoses
A composite hose is a construction in which several film or fabric layers and support elements work together. It is not evaluated like a one-piece rubber hose; the inner and outer wire, layer materials and end assembly …
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Chemical and fuel service with composite hoses
When selecting a composite hose for chemical and fuel transfer, a 'chemical hose' or 'fuel hose' label alone is not sufficient. The composition of the fluid, layer and wire materials, cleaning condition, pressure and el…
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Electrical continuity in composite hoses
The electrical continuity of a composite hose is evaluated on the finished assembly using a defined measurement method. The acceptance limit is not a single number for all composite hoses; it must be taken from the manu…
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End fittings and assembly limits for composite hoses
The end assembly of a composite hose is not a generic fitting choice independent of the hose body. The hose series, layers, wire construction, fitting and assembly method must be verified together; haphazard re-tighteni…
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Storage and inspection of composite hoses
Storage and daily inspection of composite hoses must be planned so as to protect the wire and layer construction. Sharp bending, torsion, dragging and unsuitable cleaning are prevented; the manufacturer's criteria are u…
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How is the thread type identified on hydraulic fittings?
To identify a thread, the parallel or tapered form, thread pitch and diameter are examined together. The sealing method of the connection must also be defined separately. The fact that parts screw together for a few tur…
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The difference between BSPP and BSPT connections
BSPP refers to the parallel and BSPT to the tapered pipe thread family; looking the same in nominal size does not mean they have the same sealing method. Thread geometry, thread standard and the actual sealing surface o…
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Comparing NPT and NPTF definitions
NPT and NPTF are not the same thing. NPT is evaluated within the scope of the general-purpose pipe thread standard, and NPTF within the scope of the Dryseal design. Similar size and taper do not prove that the connectio…
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Identifying diameter and pitch on metric connections
A metric thread is defined by diameter and pitch; for example, the numbers in M18×1.5 state the nominal thread diameter and the pitch in millimeters. This information alone does not describe the fitting's seating surfac…
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Reading pitch on UN and UNF threads
In unified inch thread designations such as UN and UNF, the nominal diameter and the number of threads per inch are read together. Recognizing the thread family does not on its own determine whether the fitting is a JIC…
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Sealing surface of JIC flare connections
In a JIC 37° connection, the primary seal is provided by the mating of matching male and female conical metal surfaces; the thread mainly generates the clamping force. A thread that engages does not show that the conica…
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ORFS face seal connections
ORFS is a connection family that seals at the face with an O-ring. The flat face, O-ring groove, mating face and the correct seal work together; a matching thread size alone is not sufficient for a proper assembly.
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Series distinction in metric 24-degree connections
In 24° metric connections, the tube diameter, connection type and L/S series information are required in addition to the thread size. The light and heavy series names are not sufficient for selecting by appearance or fo…
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Distinguishing a BSP thread from a cone seating surface
A BSP thread identifies only the thread family of the connection; it does not on its own explain whether sealing is achieved with a flat seal, an O-ring, a cone seat or on the thread. For the correct fitting, the thread…
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The role of the O-ring in ORB port connections
O-ring boss is a design that seals with an O-ring in a parallel-threaded port connection. Unlike ORFS, sealing occurs in the port area; the port geometry and the seal must both be correct.
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Selecting straight and elbow fittings
The choice between straight and elbow fittings is made according to the layout on the machine and the natural route of the hose. Using an elbow can reduce forced bending; however, pressure loss, access, orientation and …
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Swivel nut fitting vs. rotary swivel joint
A nut that can turn during assembly and a swivel joint designed for continuous rotation during operation are not the same. When the term 'swivel fitting' is used, which movement is permitted must be verified from the ma…
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Checking for restriction in reducers and adapters
A reducer or adapter can resolve a geometric difference between two connections; however, it does not automatically equalize the pressure, material and sealing suitability of different parts. Each added part is evaluate…
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Defining the angular orientation of a hose with two elbows
On a hose with two elbows, the orientation of the ends relative to each other is an order detail as important as the length. If it is not clearly defined from which end and from which viewing direction the angle is meas…
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Selecting fitting material and plating
The material and plating of a fitting should not be selected on the basis of appearance or color. Fluid contact, the external environment, temperature, galvanic interaction and the manufacturer's mechanical limits are e…
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