Technical field The present invention relates to a method and a device at a pump, more specifically a method and a device for enclosing a pumping unit driven by an external power source, such as electromagnetic, electrical or pressurised.

Technical background Industrial pumps of different kinds are in most conventional cases equipment that the average engineers do not think much about. They are standard components that run until they brake down, it is just that simple. In certain industrial applications, however, requirements are extremely high, i.e. when pumping sensitive constituents like for instance highly corrosive, poisonous or explosive substances, simply clean water or when pumping in sensitive environments where so called clean-rooms are common and daily practice. Such pumps may not contain metallic components at all, at least not on their wet-side. These requirements in combination, i.e. non metallic pump components in combination with zero tolerance for leaks due the harmful and/ or valuable substances that are to be pumped, do not comply with one another. Previ- ously known pumps where metallic components are not allowed to get in contact with the pumped fluid, suffer from the same basic problem, namely that they are known to sooner or later start leaking. This has to do with the fact that all the pumping elements involved are to be manufactured from non-metallic materials and that such materials do not posses dimensional stability properties enough to make it possible for them to keep their exact original shape from time to time. Nevertheless pumps must in certain contexts be made from non-metallic materials, since otherwise the metallic components would contaminate the pumped products. Thus, if pumps are to be manufactured from non-metallic materials, i.e. plastics, doubtful dimensional stability is a problem that as of yet has not found its solution. Pumps of this known kind has until now normally been provided with mechanical bolt joints, including pin bolts or clamp bolt joints, to keep the respective parts together and the basis for the present invention lies in that it is believed that it is the combination of different materials that give rise to the problem.

It is therefore an object of the present invention to provide a method and a device at a pump, for instance a diaphragm or a double diaphragm pump, to keep the pump elements together and that even if the pump-elements themselves starts leaking, will keep the leaked amount to a minimum that in an almost failsafe manner will keep it enclosed and prevent it from reaching the surrounding environment.

According to the invention the pumping unit with connections thereto is contained snugly fit in a casing, ends of which in use are closed at one first end of the casing by the use of co-operating internal and external shoulders respectively, and at another, second end, by the use of a lid being compressed against said pumping unit and held in position by an internal cylindrical locking washer, arranged in an internal groove in the casing, thus keeping elements of the pump together.

By the proposed construction a completely hermetical containment of a pump is possible, thus making it possible to produce pumps of a less form stabile material combination and yet provide a completely safe product.

In a further developed embodiment of the invention the locking washer in its turn is being completely secured in place by a fixation ring member/washer, fitted in a suitably ring shaped groove in the bottom surface of the casing, between the locking washer and a shoulder provided on the outside of the lid. Hereby the locking washer is completely securely kept in place. The principle of locking the locking washer in this fashion safeguards any and all risks that the locking washer for any reason would let go of its engagement in its groove due to for instance vibrations from driving the pump inside the enclosure. The locking principle also gives rise to a possibility of stacking pump units enclosed in the proposed fashion atop of each other in order to inter alia save space in an industrial environment. This lastly mentioned feature may also be convenient in circumstances where large quantities are to be pumped. According to a further preferred and further developed embodiment of the invention the lid during fitting of said locking washer is compressed against the force of a rigid rubber spring, arranged between the bottom of the pumping unit and said lid. Using this principle represents a very smooth solution to provide an over time constant pressure that is easy to adapt to pumping of all kinds of different liquids, that may be extremely valuable and also harmful to the environment.

In yet a further developed embodiment of the invention the pumping unit is contained inside said casing using sealings between firstly the on the one end of the cylinder arranged shoulder and a shoulder on the pumping unit and secondly between the lid and the locking washer. By so doing an if possible even safer enclosed pumping unit is achieved that having once been enclosed in this sealed fashion is believed to be in service for an indefinite period of time extending for a period until the pumping unit gives in.

Brief description of the drawings

The invention will in the following be described in further detail, reference being given to a preferred embodiment example shown in the accompanying drawing figures, in which: Fig. 1 is a view with all parts separated of a diaphragm pump together with an enclosure thereto, and

Fig. 2 is an enlarged view with parts separated more in detail of a second end closure of an enclosure of a pump unit subject to being sealingly enclosed.

Detailed description

In fig. 1 is shown a diaphragm pumping unit with its parts separated, the main parts thereof indicated with an A. Without in detail describing the pumping unit, it comprises the following co-operating components. The main parts of said pumping unit A are comprised of a center-block 1 provided with seats for diaphragms 2, 3 respectively at each circular end thereof, each one thereof supposed to work with compressed air on its one side and a medium to be pumped on its other side, such that both diaphragms work as a driving unit as is conventional on diaphragm pumps. A rod 4 connects the two diaphragms 2, 3. As is conventional with pumps of this kind, said center-block 1 is provided with all kinds of necessary sealings like O-rings 17, at least one air valve and different kinds of non return valves, necessary for the function of the pumping unit, however, not for the invention as such. As a consequence these parts are not further discussed in this context.

Said pump, however, comprise a top cover 5 and a bottom cover 6, each absolutely necessary for the function of the pumping unit, the main parts of which as mentioned above are indicated with an A. When fully assembled said pumping unit has the shape of a cylinder, apart from the fact that its circular upper border line on the top cover 5 is provided with a circularly and perpendicularly shaped recess 7a supposed to matingly be able to fit with a shoulder 7b at an utmost upper inner part of a cylindrical casing 8, in which the complete pumping unit is to be arranged in a sealed fashion.

The fully assembled pumping unit A is dimensioned to snugly fit inside so that it with some resistance can be slided into position into said casing 8 and when fully inserted in the casing will rest against said shoulder 7. The length of the cylindrical pumping unit is such that it will be completely contained inside the cylindrical casing 8. When mounting the pumping unit A in said cylindrical casing 8 also the bottom end of the cylinder must be closed. The lower end surface of the pumping unit is completely plain, except for possibly a recess or other machined pattern for the arrangement of a sealing at its perimeter.

As is better shown in Fig 2, a lid 9 is provided to close the casing 8 when the pumping unit has been properly inserted. Between the bottom end of the pumping unit A and the lid 9, a circular rubber spring 10 is arranged. The fit of the lid 9 is the same as that of the pumping unit inside the cylindrical casing 8. To keep the lid in place inside the cylindrical casing, one or more locking elements must be securely arranged inside the same number of grooves/recesses, preferably a locking washer 11 inside a groove (not shown), at the inner lower end part of said casing 8. For fitting thereof is required a compression of said rubber spring 10, situated on the inside of the lid 9. This is, however, fairly easily achieved by the use of a conventional industrial press. The rubber spring 10 is upon fitting arranged around a preferably machined shoulder 12 on the inner side of the lid 9.

On the other side of said lid 9 there is another shoulder denominated 13. The size thereof is at least that much smaller than the opening of said cylindrical casing 8, that there is room enough for fitting the locking washer 11 in its groove. On the same side of said lid 9 is in the version shown in Fig 2 arranged a sealing 16 for hermetically sealing the pumping unit twice. The reason why this is only shown here is that the sealing comes with an alternative embodiment of the invention for extreme purposes. Such a sealing 16 is in the same alternative embodiment also arranged at the other end of said pumping unit, thereby making it fully hermetically sealed in the casing 8.

Correctly fitting the locking element/-s 11 in its/their groove/-s leaves a circular space on the inside of the locking washer 11 into which a step-shaped ring-washer 14 is snugly fit. Rubber feet 15 are finally fixed in holes (not shown) on the lower outer surface of the lid 9. By said feet 15 the complete sealed unit, including the cylindrical casing 8 may stand upright without transferring its vibrations to its standing surface. There are preferably four such feet 15, which when fitted and the pump stands on them during service, effectively keeps the ring-washer 14 in its place unaffected by any vibrations.

Alternatively this ring-washer 14 may be omitted in a case where there is need for arranging more than one pump. The upper cover 5 are for such purposes designed to be able to replace said washer 14 and is for this purpose a bit higher than otherwise as well as shaped as a ring protrusion, whereby a very stabile mounting principle is established, allowing an infinite number of pumps to be stackable atop of each other, preferably clamped together by external elements (not shown).