Leak

A leak or a leak is a hole in a product or in technical systems, can undesirably enter or exit through the solids, liquids or gases. A leak can result in the failure of an entire technical system. A measure of the extent of any leakage, the leakage rate (see tightness).

• 5.1 Defined leak sizes
• 5.2 Undefined leak sizes

Relationship between hole size and leak rate

Tightness in the technical sense means only " free from leaks according to the technical field of use ". A closer look at the provided requirements for technical systems are very different.

For the relationship between the hole size and the associated leakage rate the following rough estimates apply:

Types of leaks

Leaks are divided according to the type of characteristics into the following groups:

• Hole leakage ( clearly visible )
• Turbulent - leakage ( whistling gas leakage)
• Laminar leakage (leakage in detachable or non-detachable connections, such as in flanges, welds, etc.)
• Molecular leakage (including pores leakage, leakage caused by the finest pores, or injury in the polycrystalline structure of the material )
• Virtual leakage (apparent leakage, caused by the evaporation of liquids or by outgassing )
• Kalt-/Warmleckagen (reversible leakage that occur only under extreme temperature stresses )
• Valve leakage or folding leakage (leakage with preferential flow direction)
• Lambda leakage (leakage that occur in the liquefaction of helium)

No leakage in the classical sense is the material-specific gas permeability ( permeation) of a material.

Ship leak

A leak (hole) in a vessel leads to the penetration of water into the ship's interior. When a leak below the water line, the water penetrates through the acting from the outside water pressure. When heeling of the ship, a leakage and above the waterline by submersion under the water level to prevent water entry. Through open or embarked hatches or windows or through leaks in the hull water can penetrate ( " flooding "). Even heavy rain and waves can cause a larger flooding depending on the location of the leak.

The penetrating water can affect the stability of the ship or bring it to sink.

Leakage current

The leakage current (the amount of water flowing per unit of time ) is measured in liters / minute or cubic meters / hour.

Crucial to the leakage current are:

The leakage current is the greater, the lower the leakage is below the water level, the greater the leakage, the greater the diameter and Einschnürzahl (the round hole ) is. From the buoyancy of the vessel and the leakage current can be calculated how long a ship floating in theory or (if it will not capsize before).

Causes

Causes can be:

Leakage control

For small leaks the penetrated water can be pumped out with a bilge pump or scooped out with a bilge bucket. It is crucial that the amount of inflow is as small as the pump power. Even if the pump power is smaller, it delays the net leakage current and extends the time available for leak detection and seal. An effective measure is the ship to heel so that doing the leak comes to lie as high as possible, ideally above the water level. For small leaks, it is also effective to seal immediately with a body part the hole by contrast pressures.

Large ships are divided by locks in watertight chambers inside. If the locks of the damaged chamber are closed, the ship can be further maneuverable even with a flooded chamber.

Goal of any leakage reduction is the possible permanent closure of the leak, for example by pressing a counter plate and wedging it with wood or metal supports.

Leak on boat

Licking a dinghy, so for now escapes only air from a chamber. It sinks until the remaining buoyancy chambers all being less than the weight of boat plus charge.

Leak in pneumatic tires

Leaks in air tires ( with or without inner tube) may behave very differently. An engaging foreign bodies, the leak at rest or a certain route long seal. Small leaks can almost completely close at sufficiently abgesunkenem pressure. A leak can be glued with a special sealing liquid from the inside or repaired tubular tires with a patch on the tube.

Leak size

The Störfallverordnung sets defined and undefined leak sizes.

Defined leak sizes

Emissions over the following defined leak sizes:

• A hose demolition when transferring
• When blowing off through the safety valve
• Breaking the rupture disk
• Overcrowding in the tank pit
• The failure of a flange

Undefined leak sizes

• Plan view of a weld seam of a tube or in the wall of a container.
• Broken water pipe or a general burst pipe ( sewer pipes )
• Bursting a hose