Technical

Glossary

The most important terms around quick-release couplings, mould temperature control and seals – briefly explained.

B C D E F H I L M N O P Q R S T U V W

Back-up ring: Ring made of a harder material, e.g. PTFE, that sits next to an O-ring in the groove. At high pressure it prevents the O-ring from being pressed into the sealing gap and damaged (gap extrusion). Typical in hydraulic couplings.
BSP / G: British Standard Pipe – parallel Whitworth pipe thread with 55° flank angle to ISO 228-1, designated G in Germany. Read more →
BSPT / R: British Standard Pipe Taper – tapered Whitworth pipe thread to ISO 7-1, seals in the thread. Male thread R, female thread Rc. Read more →
Bulkhead fitting: Fitting that is passed through a wall or sheet and secured with a lock nut. This allows lines to be routed neatly and tightly through housing or machine walls. Read more →
Bulkhead plate: Plate in a housing or machine wall through which couplings or nipples are passed and fastened with a nut. This creates a fixed, clean connection point to the outside, e.g. on the temperature control unit. Versions with bulkhead connection (code SA) are available for mounting. Read more →
Burst pressure: Pressure at which a component fails. It is several times higher than the operating pressure – this margin is the safety reserve.
Cascade: Cascade injection moulding: the nozzles of a valve-gate hot runner open one after the other instead of simultaneously. This allows large or long parts to be filled without visible weld lines. The needles are usually actuated hydraulically or pneumatically – connected e.g. via the MPC multi coupling. Read more →
Chemical resistance: How much a seal material is changed by a medium. Rated from A (no to slight change) to D (not recommended). Read more →
Chiller: Cooling unit that brings cooling water to a low, constant temperature and pumps it through lines to the machine, to temperature control units or directly to the mould. Counterpart to the temperature control unit, which usually heats. Read more →
Circlip DIN 471 / DIN 472: Spring retaining ring that secures components axially. DIN 471 sits externally in a groove on a shaft or pin, DIN 472 internally in a groove in a bore. Fitted with circlip pliers.
Collector: Bar with one inlet and several outlets that distributes the medium to several circuits. At FLEXQ in brass, aluminium or stainless steel. Read more →
Connecting under pressure / residual pressure: If pressure is still present in the line, e.g. because trapped medium has heated up, the valves must be opened against this pressure when connecting. Many couplings are then difficult or impossible to connect. Remedy: depressurise the line before connecting or use couplings with pressure relief.
Connection size: Size of the thread or hose barb to which the part is connected, e.g. BSP 3/8" or hose Ø 13 mm. Read more →
Cooling circuit: A channel in the mould with supply and return. Two connections are needed per circuit. Read more →
Core pull: Movable core in the injection mould that forms undercuts or cross holes in the part and is pulled out before demoulding. Core pulls are usually actuated hydraulically – connected via hydraulic couplings, e.g. the HPF, PPT or SPF series. Read more →
Corrugated hose: Hose with a corrugated inner core made of fluoroplastic (PFA or PTFE) and a stainless steel braid. The corrugation makes it flexible and kink-resistant, the fluoroplastic core resistant to high temperatures and aggressive media. At FLEXQ the BTH-UF (PFA) and BTH-UFT (PTFE) series, with union nuts at both ends. Read more →
Coupling: The female part of a quick-release coupling with locking sleeve. First letter of the code in the part number: F. Read more →
Coupling profile: Shape of the plug connection, e.g. European profile (HPT), international profile (IPT) or French profile (MPT). Only identical profiles fit together. Read more →
Direction of flow: Direction in which the medium flows. Rule at FLEXQ: the nipple is at the start of the hose, the coupling at the end. Read more →
Ejector side: Moving half of the injection mould, where the parts are ejected. Counterpart to the nozzle side. Read more →
EPDM: Ethylene propylene diene rubber. Good resistance to water, hot water, steam and many acids, not suitable for mineral oils. FLEXQ code E. Read more →
European profile: The most widely used coupling profile in temperature control technology – especially for the connections on injection moulds in Europe. Couplings and nipples with European profile fit together across manufacturers, provided the profile and nominal size match. At FLEXQ the HPT series. Read more →
Extension: Tube between mould and coupling or nipple to reach deeper connections. Version "without thread": the customer cuts the thread.
Female thread: Thread inside the part that takes a male thread. Code in the part number F (BSP) or N (NPT). Read more →
FFKM: Perfluororubber (e.g. Kalrez®). Highest chemical resistance for very aggressive media. FLEXQ code W. Read more →
Fitting light / heavy: Series of compression fittings to DIN 2353 / ISO 8434-1: L (light) and S (heavy) with different threads per tube size. Read more →
FKM: Fluororubber (e.g. Viton®). Resistant to oils, fuels and high temperatures up to approx. +200 °C. FLEXQ code V. Read more →
Flat face: Coupling design with flat front faces. Practically no medium escapes when disconnecting, and hardly any air is trapped when connecting. Typical for hydraulics. Read more →
Flow curve (Δp curve): Diagram showing the pressure drop Δp (in bar) against the flow rate (in l/min), usually with logarithmic axes and one curve per nominal size. How to read it: find the flow rate on the horizontal axis, go up to the curve of the nominal size and read the pressure drop on the left. Read more →
Flow monitoring: Continuous measurement of the flow rate in each cooling circuit, usually with display and alarm. Blocked, scaled or incorrectly connected circuits are detected immediately, before they lead to rejects or longer cycle times. Further information can be found here ↗.
Flow rate: Quantity of medium flowing through the coupling per unit of time, usually in l/min. Depends on nominal size, profile and pressure drop. Read more →
Free flow: Coupling without shut-off valve – full cross-section and low pressure drop, but the medium runs out when disconnecting. Read more →
French profile: Coupling profile that is mainly used on moulds from France or from French mould makers. It is not compatible with the European profile or the international profile. At FLEXQ the MPT series. Read more →
HEX / spanner size: Dimension across the flats of the hexagon in mm – determines the right tool for screwing in.
Hose barb: Connection onto which a hose is pushed and secured with a clamp. Code H in the part number.
Hose clamp: Clamping ring that holds a hose tightly and securely on the hose barb. Depending on the application as worm-drive clamp (SS), T-bolt clamp (GBS), single-ear clamp (EOS, EEOS) or two-ear clamp (ZOS). The size depends on the outside diameter of the hose on the barb (clamping range). Read more →
Hydraulics: Power transmission with pressurised fluid, usually hydraulic oil, at high pressures of up to several hundred bar. In mould making e.g. for core pulls, ejectors and valve gates. Dedicated, pressure-resistant hydraulic couplings are used, often flat face. Read more →
International profile: Coupling profile that originally comes from the USA and is mainly used on moulds from the American region. It is not compatible with the European profile. At FLEXQ the IPT series. Read more →
ISO 16028: Standard for flat-face hydraulic quick-release couplings – at FLEXQ the HPF series. Read more →
ISO 7241-1 Series B: Standard for hydraulic quick-release couplings with ball locking – at FLEXQ the PPT series. Read more →
Liquid thread sealant: Liquid thread sealant that cures between the threads, sealing the thread and securing it against loosening. Alternative to PTFE tape, especially with vibration and for fast, clean assembly. Read more →
Machine side (MP): Part of the multi coupling at the machine or temperature control unit, with locking, usually fitted with couplings. Read more →
Male thread: Thread on the outside of the part, screwed into a female thread. Code in the part number e.g. M, R, O or T. Read more →
Mould side (FP): Part of the multi coupling on the mould, usually fitted with nipples. Counterpart to the machine side. Read more →
Mould temperature control: Targeted heating or cooling of the injection mould via cooling circuits – decisive for cycle time and part quality. Read more →
Multi coupling: Plate that connects many circuits simultaneously with one movement – fast mould changes without risk of mix-ups. Read more →
NBR: Nitrile rubber – standard seal at FLEXQ. Good for water, mineral oils and hydraulic oils, approx. −15 to +100 °C. Code N. Read more →
Nipple: The male part of a quick-release coupling that is plugged into the coupling. First letter of the code in the part number: M. Read more →
Nominal pressure (PN): Rated pressure level of a component in bar. It indicates the permissible pressure at room temperature and is used to select suitable components.
Nominal size (DN): Figure for the bore of the coupling in mm, e.g. DN 9. Determines flow rate and size.
Nozzle side: Fixed half of the injection mould on the injection nozzle side. Counterpart to the ejector side. Read more →
NPT: National Pipe Taper – American tapered pipe thread with 60° flank angle to ASME B1.20.1. Cannot be combined with BSP/BSPT. Read more →
Operating pressure: Maximum pressure to which a coupling may be subjected in continuous operation. It is at most the nominal pressure and may be lower at high temperatures.
Outlet: Direction in which the hose or line leaves the coupling: straight, 45° or 90°. Shown in the part number as suffix -45 or -90; no suffix means straight. Read more →
Parking plate: Holding plate at the machine on which the machine side of the multi coupling is placed when the mould is disconnected. Read more →
Parting line: Plane at which the two mould halves separate when opening.
PFA: Perfluoroalkoxy polymer – a fluoroplastic with very high chemical resistance, usable up to approx. +200 °C in FLEXQ corrugated hoses. Can be processed like a thermoplastic. Core of the BTH-UF series. Read more →
Pneumatics: Power transmission with compressed air, usually up to approx. 10 bar. In mould making e.g. for valve gates, valves and blow-off. Suitable FLEXQ couplings include the PBP push-button coupling. Read more →
Pressure drop: Loss of pressure when flowing through coupling and nipple. The larger the nominal size and free cross-section, the lower the pressure drop.
Pressure relief (pressure eliminator): Feature in the coupling that releases trapped residual pressure so that the coupling can be connected despite residual pressure. At FLEXQ as option P, e.g. on the hydraulic series SPF and SXF. Read more →
PTFE: Polytetrafluoroethylene (known as Teflon®) – fluoroplastic with almost universal chemical resistance and very low friction, usable up to approx. +260 °C. Core of the BTH-UFT series, also used as thread sealing tape and seal material (code T / TD). Read more →
PTFE tape: Thread sealing tape made of PTFE, wound clockwise onto the male thread before screwing in. Reliably seals parallel and tapered pipe threads. Read more →
Push-button coupling: Coupling that is released by pressing a button instead of pulling back the sleeve. This allows easy one-handed operation, even in places that are difficult to reach. At FLEXQ the series PBW for fluids, PBP for pneumatics and PBH for hydraulics. Read more →
Push-in barb: Barb for push-on hoses that holds securely without a clamp. Code P in the part number.
Push-on hose: Hose that is pushed onto a push-in barb without a clamp.
Push-pull: Coupling design that locks by pushing in and releases again by pulling the sleeve. Read more →
Quick-release coupling: Connection of coupling and nipple that can be connected and disconnected in seconds without tools. Read more →
Return: Line in which the medium flows back from the mould to the temperature control unit – usually marked red.
Return collector: Collector bar that brings several returns together. Often mounted on the mould together with a collector for the supply. Read more →
Safety lock: Additional lock against unintentional disconnection, e.g. due to knocks, pulling on the hose or vibration – important with hot media, high pressure and moving moulds. FLEXQ offers three versions: S – bayonet lock on the sliding sleeve with a ball; to disconnect, the sleeve is first turned until the ball leaves the locking position, then pushed back. SR – lock with a nut that is turned against the sleeve and blocks its sliding movement; to disconnect, the nut is turned back. SL – safety lock on the locking block of the multi coupling: the lever can only be turned in the opening direction after it has been pulled upwards. The code is at the end of the part number. Read more →
Seal material: Elastomer of the seals in coupling and nipple. At FLEXQ: NBR (standard), EPDM, FKM/Viton® and FFKM/Kalrez®. Selected according to medium and temperature. Read more →
Single-ear clamp: Hose clamp with one "ear" that is pressed together with pliers. Narrow, clamps evenly all round and has no protruding screw. At FLEXQ as EOS (without inner ring) and EEOS (with inner ring, protects the hose). Read more →
Stainless steel VA / V4 / IA: Stainless steel versions at FLEXQ: VA = V2A (1.4301, standard), V4 = 1.4305, IA = stainless steel S4. The code is at the end of the part number. Read more →
Supply: Line in which the medium flows from the temperature control unit to the mould – usually marked blue.
T-bolt clamp: Robust hose clamp with bolt and nut that produces a high, even contact pressure. For larger hoses, higher pressures and temperatures. At FLEXQ series GBS. Read more →
Tap drill hole: Hole drilled before tapping a female thread. Diameter for each thread in the thread table. Read more →
Temperature control unit: Unit that keeps the mould at a constant temperature using water or oil. Read more →
Test pressure: Pressure applied briefly to a component during testing to prove tightness and strength. It is higher than the operating pressure and not intended for continuous operation.
Thread code: Numerical code for the thread size in the part number: 18 = 1/8", 14 = 1/4", 38 = 3/8", 12 = 1/2", 34 = 3/4", 10 = 1". Metric e.g. 1415 = M14 × 1.5. Read more →
Two-ear clamp: Hose clamp with two ears that is pressed together with pliers. At FLEXQ as ZOS, also in stainless steel (IA). Read more →
Union nut: Nut with female thread on the hose end or on a fitting, e.g. on corrugated hoses. Read more →
Valve: Shut-off valve in coupling or nipple that closes when disconnecting. Third letter in the part number: B = with valve, F = without valve. Read more →
Worm-drive clamp: Hose clamp with perforated band and screw, tightened with a screwdriver or socket. Wide clamping range, releasable and re-tightenable – the classic for water hoses. At FLEXQ series SS, also in stainless steel (IA). Read more →

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