physics

Hose coupling

Hose coupling is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hose coupling rather than just read about it. In short: A hose coupling is a connector on the end of a hose to connect (or couple) it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel, brass, stainless steel, aluminium or plastic.

Key takeaways

Hose coupling belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hose coupling to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hose coupling from memory before moving on to harder problems.

Reference excerpt

A hose coupling is a connector on the end of a hose to connect (or couple) it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel, brass, stainless steel, aluminium or plastic. Due to the great variety of the designs and the number of countries in which they were created, it is difficult to trace the origin of many. Patents that cover designs similar to those below include:

1876: Hose-coupling, No. 175,232. Coupling for hose and pipe. US 894900 A 1915: Coupling. US 1248558 A 1931: Coupling. US 1947593 A (claw-types)

Threaded coupler types

Garden hose thread See Garden hose thread. See also Hoselink and Hozelock plastic click-on connectors.

GFR NF E 29-579 GFR

Ground joint A "boss" ground joint coupling valve hose coupling, primarily used for compressed air or steam. It consists of a stem, wing nut and spud. It seals as a soft copper seat located in the spud is drawn against the stem by tightening the wing nut.

Holedall Holedall (a.k.a. Mulconry, Scovill, or Rostra) dock hose couplings are built to the BS EN 1765:2004 "Rubber hose assemblies for oil suction and discharge services Specification for the assemblies", commonly known as dock hoses. These are internally swaged hose couplings and commonly found on larger diameter fuel oil hoses used in higher pressure applications or where the hose is exposed to higher end pull, e.g., Oil Suction & Discharge (OS&D) hose). They are installed with special hydraulic ram machinery and special dies. Holedall IX internally expanded (internally swaged) hose coupling is used in higher pressure applications, or where the hose is exposed to higher end pull, or where a full flow is required. They are installed with special hydraulic drawbar machinery, using special pull plugs.

National Hose thread (NH), also known as National Standard Thread (NST). It is the most common type of fire hose coupling used in the United States. The male and female straight (non-tapered) threads screw together and the connection is sealed with a gasket. The type of threaded coupling with a pin-lug swivel used on fire hoses was first manufactured prior to 1873 in the U.S.:

Unknown patent by Charles W. Emery, dated July 11, 1865, 1874: Hose-couplings, No. 149,029 by W. A. Caswell 1874: Hose-couplings, No. 149,441 by W. A. Caswell, describes a method of casting the hose tail inside the coupler, so that it can pivot but not be detached. 1876: Hose-coupling, No. 175,232. Despite the age of these couplings, incompatibilities still exist.

UNI UNI Fire Fittings are used in Italy, and available in several sizes, including UNI 25, UNI 45, and UNI 70.

BS336 The suction hoses and pump intakes of UK fire appliances use a round thread form of 3 threads per inch and either 4 or 5-1/2 inches diameter. The male and female threads fit quite loosely so that they can be assembled quickly even when dirty. A rubber washer forms the seal.

Non-threaded gendered coupler types

Camlock

A camlock, also called cam and groove, is a quick connect fluid transfer hose coupling that consists of a male "adapter" and female "coupler". The adapter has a groove on the outside that is engaged by the "cam arms" on the outside of the coupler to effect a seal against the gasket inside the "coupler". They are commonly used for petroleum or chemical applications. Specified by Mil-C-27487 / A-A-59326A / EN 14420-7 / DIN 2828.

Perrot Cardan coupling Similar in appearance to Bauer couplings, but not compatible with them. Used in agricultural, irrigation, cleaning, and construction industries, but most commonly for water, mortar, bitumen, and bulk products.

British instantaneous coupling

Also called John Morris Coupling, BS336 Instantaneous fire couplings are similar in design to the camlock fittings, and are used by UK, Irish, New Zealand, Indian and Hong Kong fire brigades. They are available in two sizes: 1+1⁄2-inch INST (FETA, only available with 38 mm hose tails) and 2+1⁄2-inch INST (BS336).

Hozelock In 1959 Hozelock Ltd in the United Kingdom invented and patented the international standard plastic, click-on style, push-fit hose end connector now used with garden hoses. The concept was developed to replace metal hose end connectors in coal mines, which were prone to cause static sparks and the possibility of methane gas explosions. All-metal versions of the connector (and compatible with the plastic versions) are now in common use for garden hoses. The system is now universally used by gardeners throughout the world. The Hozelock brand adapters are typically available with BSP threads. There are two different sizes of the connectors available, with the larger one being rare and mainly used on +3⁄4-inch hoses.

Leverlock A cam and lock-like coupler, used in the agricultural industry. Also known by the brand names of manufacturers, including Bauer, Perrot, and Miller/Ferrari. Available in sizes ranging from 2-inch to 12-inch.

Machino A Japanese quick connect and disconnect coupling used on fire hoses in Japan and defined by JIS B9911; available in several sizes: 25A (1-inch), 40A (1+1⁄2-inch), 50A (2+1⁄2-inch), 65A (2" ), 75A (3-inch).

Tankwagen flange couplings A.k.a. TW couplings, or tanker couplings, these were originally defined by DIN 28450, but are now specified by EN ISO 14420-6. The couplings are widely used in the petrochemical, chemical, and food industries.

Quick-connect garden hose couplings A variety of manufacturers sell the same style quick-connect garden hose coupling. The design is similar in concept to the plastic Hozelock design, in that the female coupling has a spring-loaded outside barrel that locks onto the male coupling, but both couplers are usually made of brass and the male coupling lacks the rubber O-ring found on the Hozelock couplers.

Non-threaded genderless coupler types Many of these couplings are of the so-called "claw" type. Some of the information below has been taken from commercial product catalogs and specifications.

Air King The "Air King" universal air hose coupling, also known as a "Chicago style" fitting, is malleable iron or brass "quarter turn" "sexless coupling" usually found on large pneumatic tools like jackhammers. The fitting is considered "universal", because a common two-lug head is used on all sizes ranging from 0.25 to 1 inch (6 to 25 mm).

Barcelona

… excerpt ends here. Continue reading the full article.

Illustrations

Hozelock-compatible garden hose couplers (Gardena brand)

Perrot-brand Bauer-style hose couplings

Worked examples

Example 1 — a first encounter with Hose coupling

Start with the simplest possible case. Write down what Hose coupling claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hose coupling before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hose coupling ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hose coupling

In research: Hose coupling appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hose coupling in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hose coupling is common in secondary-school and first-year university syllabi. It links to neighbouring topics Firefighting equipment, Hoses, Seals (mechanical), so understanding it makes those chapters shorter.
In everyday life: Look for Hose coupling outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hose coupling in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hose coupling means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hose coupling out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hose coupling in simple terms?

Why does Hose coupling matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hose coupling?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hose coupling.