EP0624434A1 - Liquid gas quick connection - Google Patents

Abstract

1. In the case of liquid gas quick connections (couplings) for connecting the side valves of a tanker (tank wagon) to the liquid- and gas-phase charging arms for the charging and discharging of liquefied gases, with connecting flange with pipe piece and male part, union nut and sealing ring, according to the prior art, the object is to further improve the security of the closure system and to achieve reductions in the charging times. The innovation consists in a union nut/wrench combination with the following features: a) the union nut has an outer ring with holes passing in the axial direction through the same at specified distances from one another, b) an arcuate wrench part, corresponding in its dimensions approximately to a reference circle of the outer ring, has two pins whose dimensions and distances from one another on the wrench part are dimensioned so that on attachment of the wrench the pins positively engage in the holes of the union nut which are made in the outer ring, c) the wrench part merges at one end into a lever arm for actuation of the wrench in the form of a hand lever for loosening and tightening the union nut. <IMAGE>

Description

The invention relates to a liquid gas quick coupling as a connection of the side valves of a tank car with the loading arms of the liquid and gas phase for loading and unloading liquefied gases with a connecting flange with a tube piece and male part, union nut and sealing ring.

With such liquid gas quick couplings, the connections between the gas tank car and the stationary tanks are made. They have to meet certain safety requirements, which have to be taken into account for the transport and handling of dangerous goods by rail, e.g. type approval from the German Federal Railways or type examination from the TÜV. Individual parts for LPG quick couplings are supplied by relevant manufacturers as components and are u. a. described in DIN 26 031.

Liquid gases are to be understood in particular as ammonia and the hydrocarbons propane, propene, butane, butene and mixtures thereof.

The demand for unconditional security of the locking system on compressed gas tank wagons for the transport of liquefied gases has been followed in recent years by the demand for shorter loading and unloading times. Although the fittings in use were relatively safe, it is always desirable to improve usability and safety.

The conditions are explained below using the example of liquid gas loading in tank wagons. A tank car is filled via loading arms with a connector of 80 mm nominal diameter for the liquid phase and a connector of 50 mm nominal diameter for the gas phase for the purpose of gas oscillation between the stationary tank and tank car via the two side valves. For this purpose, the loading arms are attached and detached on the track scale, so that two flange connections of nominal widths 80 and 50 mm with a total of twelve M 16 screws, including insertion of the flange seals in the recess of the valves, have to be loosened or manufactured for each tank wagon is relatively time consuming.

The shortening of the assembly time on the track scale for the two loading arms fails due to the current constructions for the union nut with cams attached to the outer circumference and a suitable key for loosening them.

A key designed as a hand lever overlaps two cams on a partial circumference of the union nut when it is attached with a key part having a movable chain link such that the circumferential force required to release the threaded connection is transferred to the cams by means of leverage. The design of the key with a movable chain link should allow the key to be attached even if the cams of the union nuts are damaged or have burrs.

But even without such damage, the combination nut and wrench with a movable chain link is not clearly positive-locking but non-positive, which harbors the risk of slipping and injury to operating personnel. In addition, the strength of such keys is not sufficient. As a result of relaxation icing, the screw connection can become stronger, so that the clamping bracket of the key can tear when loosening such cam union nuts according to the prior art and the key is therefore unusable. This has the result that - although questionable and inadmissible for safety reasons - when difficulties arose, attempts were made to loosen or tighten the union nuts with a hammer by hitting the cams. Such violent effects led to burrs on the cams of the union nuts until they were completely unusable, in particular also through cracks and fatigue fractures on the material of the union nuts.

Because of these difficulties, for safety reasons, the practice has developed to dispense with cam nuts provided for fastening loading arms. Before loading the tank wagons on the track scale, the dummy covers DN 50 and DN 80 including the seal must be removed and the two loading arms including seal must be installed using 12 M 16 screws. After loading is complete, the loading arms are removed again and the blind covers are reinstalled after inserting another new seal.

This is where the task begins to improve the security of the locking system.

An additional subtask consists in a further reduction in loading and unloading times.

• a) die Überwurfmutter weist einen Außenkranz mit durch denselben in bestimmten Abständen voneinander in axialer Richtung geführten Bohrungen auf,
• b) ein bogenförmiges in seinen Abmessungen etwa einem Teilstück des Außenkranzes entsprechendes Schlüsselteil weist zwei Zapfen auf, deren Abmessungen und Abstände voneinander auf dem Schlüsselteil so bemessen sind, daß die Zapfen beim Ansetzen des Schlüssels formschlüssig in die angebrachten Bohrungen in dem Außenkranz der Überwurfmutter eingreifen,
• c) das Schlüsselteil geht an einem Ende in einen Hebelarm für die Betätigung des Schlüssels als Handhebel zum Lösen und Festziehen der Überwurfmutter über.

The object is achieved in that a union nut and key combination is provided with the following features:

• a) the union nut has an outer ring with bores which are guided through it at certain distances from one another in the axial direction,
• b) an arcuate key part corresponding in its dimensions to approximately a section of the outer ring has two pins, the dimensions and distances of which from one another on the key part are dimensioned such that the pins engage positively in the holes made in the outer ring of the union nut when the key is attached,
• c) the key part merges at one end into a lever arm for actuating the key as a hand lever for loosening and tightening the union nut.

The union nut according to the invention is advantageously provided with the same spacing of the bores in the outer ring even with different nominal diameters of associated pipe sections, for example 80 and 50 mm. This means that the same key fits for flanges of different nominal sizes.

Subject to type tests by the relevant technical monitoring bodies and type approvals by the rail operator, it is also possible to provide the side valves directly with a suitable threaded connection instead of the adapter pieces to be installed specially before the loading process. The side valves would be sealed during transport in both versions by means of a blind cover with a union nut.

Now the suitable transition pieces for filling with one-sided thread and flange can be installed when loading an entire train of, for example, 30 to 40 tank wagons while the previous tank wagon is being filled and before it is driven onto the track scale. This activity can range from that required to make the connections between the side valves and the reservoir via the loading arms responsible personnel are carried out in the time required to fill the previous tank car. In addition, due to shorter assembly times on the track scale, the loading time required for an entire train is reduced. There are corresponding processes for emptying. In the case of tank wagons with external long girders, correspondingly extended transition pieces can be installed, which enables unhindered connection of the loading arms on the track scale. Likewise, the transition pieces are removed again while the next tank car is being loaded and the valves are provided with blind covers for the subsequent transport.

When the combination according to the invention is introduced for all senders and receivers in Germany and in neighboring countries and all pressure gas tank wagons are equipped with transition pieces on the side valves, significant reductions in loading times or increases in loading quantities per unit of time can be achieved due to shorter assembly times.

In addition, four sealing rings (two seals each for gas and liquid phase connection piece) are saved per tank car loading.

In the case of CO₂ pressure tank wagons, valves of smaller dimensions than for the aforementioned liquid gases are required. However, the combination according to the invention can also be used advantageously here.

Further preferred features of the invention result from the following description of preferred exemplary embodiments. These exemplary embodiments are shown schematically in the accompanying drawing, which also illustrates the prior art already described.

Fig. 1:

das Prinzip der Umfülleitungen bei der Beladung eines Kesselwagens mit Druckgas

Fig. 2:

ein bekanntes System (Stand der Technik) eines Flansches mit Überwurfmutter (Nocken)

Fig. 3:

einen Vertikalschnitt durch ein Ausführungsbeispiel einer erfindungsgemäßen Schnellkupplung mit Dichtung und Anschlußstück

Fig. 4:

einen Vertikalschnitt durch ein Ausführungsbeispiel einer erfindungsgemäßen Überwurfmutter-Schlüssel-Kombination mit Draufsicht des Schlüssels

Fig. 5:

einen Vertikalschnitt durch ein Ausführungsbeispiel für eine Überwurfmutter als Drehteil sowie den Teil einer Seitenansicht von links.

The drawing shows:

Fig. 1:

the principle of the transfer lines when loading a tank wagon with compressed gas

Fig. 2:

a known system (prior art) of a flange with a union nut (cam)

Fig. 3:

a vertical section through an embodiment of a quick coupling according to the invention with seal and connector

Fig. 4:

a vertical section through an embodiment of a union nut and key combination according to the invention with a top view of the key

Fig. 5:

a vertical section through an embodiment of a union nut as a turned part and part of a side view from the left.

Claims (4)

LPG quick coupling as a connection between the side valves of a tank wagon and the loading arms of the liquid and gas phase for loading and unloading liquefied gases with a connecting flange with pipe section and male part, union nut and sealing ring, characterized by a union nut and key combination with the following features a) the union nut has an outer ring with bores which are guided through it at certain distances from one another in the axial direction, b) an arcuate key part corresponding in its dimensions to approximately a pitch circle of the outer ring has two pins, the dimensions and distances of which from one another on the key part are dimensioned such that the pins engage positively in the bores of the union nut provided in the outer ring when the key is attached, c) the key part merges at one end into a lever arm for actuating the key as a hand lever for loosening and tightening the union nut. LPG quick coupling according to claim 1 characterized by an equal spacing of the holes in the outer ring of flanges of different nominal sizes. Liquid gas quick coupling, characterized in that the side valves are provided instead of the connecting flange with pipe section and male part directly with a suitable threaded connection for a union nut designed according to the characterizing part of claim 1. Process for loading and unloading liquefied gases, characterized in that the connecting pieces of the liquid gas quick couplings on the side valves of a tank wagon are only completely supplemented by transition pieces with a union nut designed for the loading and unloading process.

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