Field of the Invention

The invention relates to an apparatus arranged for providing a liquid medium from a storage container to a system connected downstream the apparatus.

Background of the Invention

Some liquid mediums stored in storage containers are hazardous liquids. Therefore the need for a quasi-closed system is strongly given. One aspect is a protection against overflow of liquid medium in case of overpressure.

Apparatuses arranged for providing a liquid medium from a storage container to a downstream device have previously been disclosed. One example of such an apparatus is shown in DE 32 09 689 Al. This document describes a system with a fuel dispenser for liquefied petroleum gas (LPG) and an apparatus arranged for providing the LPG from a storage container to said fuel dispenser. The apparatus comprises (i) an extraction probe for extracting LPG out of the storage container, and (ii) a suction and pressure pump for sucking the LPG through the extraction probe and for feeding the fuel dispenser. The extraction probe is arranged for extending into the interior of said storage container and comprises at its inlet a valve unit with a non-return valve and an overpressure valve. Due to the non-return valve function of the valve unit at the inlet of the extraction probe the apparatus is a closed system. Because the density of LPG changes rapidly even for moderate temperature changes, in case of a predefined overpressure within the suction line and extraction probe the overpressure valve of the valve unit opens directly into the storage container.

Another reason for overpressure in the suction line and extraction probe is a pressure surge coming from/via the pump. This pressure surge can be caused by the pressure stroke of the pump in combination with a counter-pressure at the pressure side of the pump. These kind of pressure surges often occur when some kind of liquid detergents are pumped. Therefore, the object underlying the present invention is to provide an apparatus that overcomes difficulties in the context of the aforementioned pressure surges coming from/via the pump.

Summary of the Invention

This object is achieved by the invention as defined by the independent claim 1. The dependent claims detail advantageous embodiments of the invention.

According to various aspects of the invention, the apparatus is arranged for providing a liquid medium from a storage container to a system connected downstream the apparatus. The apparatus comprises:

(i) an extraction probe for extracting liquid medium out of the storage container, wherein the extraction probe is adapted for being inserted into said storage container;

(ii) a pump for pumping the liquid medium from the storage container to the system; (iii) a suction line fluidically connecting the extraction probe with the pump; and

(iv) a valve unit located at the pump side of the suction line, which valve unit comprises a non-return valve and an overpressure valve, wherein said overpressure valve opens towards the extraction probe side of the suction line in case of a predefined overpressure. The valve unit is a safety component for inline overpressure discharge. In an embodiment this valve unit is adapted for direct mounting on the pump.

In other words, the apparatus according to these aspects of the invention is an apparatus adapted for releasing overpressure on the suction side of the pump via the suction line and the extraction probe.

In another embodiment a valve of the pump located at the suction side of the pump is provided by the non-return valve of the valve unit.

According to an embodiment of the present invention, the pump is a reciprocating pump with a valve located at its suction side and a valve located at its pressure side. The reciprocating pump can, e.g., be a piston pump. In an embodiment the reciprocating pump is a diaphragm pump. This kind of pump is often used for these kinds of apparatusi, especially for hazardous liquid media.

In accordance with another aspect of the present invention, the apparatus comprises a suction lance forming the extraction probe and the extraction probe side of the suction line.

According to another embodiment of the present invention, the apparatus further comprises a flowmeter, which is located upstream of the valve unit located at the pump side of the suction line.

In accordance with yet another aspect of the present invention, the apparatus further comprises a second valve unit located at the extracting probe side of the suction line or in the extracting probe itself, which valve unit comprises a non-return valve and an overpressure valve, wherein said overpressure valve opens towards the storage container in case of a predefined overpressure. Preferably, this second valve unit is located in the suction lance.

Another embodiment of the present invention provides the valve unit or at least one of the valve units comprises a locking body, a displaceably mounted support unit for supporting the locking body, and a counter pressure element of the overpressure valve.

In an embodiment the counter pressure element of the overpressure valve is a spring device which may be a compression spring.

In general, the locking body may have any kind of shape, like e.g. disc-shaped, cone- shaped, etc. According to yet another embodiment of the present invention, the locking body is in the form of a ball (ball-shaped). The corresponding support unit of this ball shaped locking body may be a ball seat.

According to yet another embodiment of the present invention, the displaceably mounted support unit itself is supported on the counter pressure element.

In accordance with yet another aspect of the present invention, the locking body is the locking element of the non-return valve and the arrangement of the locking body and the support unit supporting the locking body is the locking element of the overpressure valve.

Another embodiment of the present invention provides the valve unit or at least one of the valve units comprises a first seal element sealing a passage between the locking body and the support unit and a second seal element sealing a passage between the support unit and a sleeve.

According to yet another embodiment of the present invention, each of the seal elements is formed as a torus- or donut-shaped seal ring. The profile of this seal ring can be circular, n-angular, X-shaped, etc. One embodiment provides one of the seal rings located radially inside the other seal ring (with or without an axial shift).

Detailed Description of the Invention

Additional details, features, characteristics and advantages of the object of the invention are disclosed in the figures and the following description of the respective figures, which - in exemplary fashion - show one embodiment and an example of a dispensing system according to the invention. In the drawings:

Fig. 1 shows an apparatus for providing a liquid medium from a storage container according to several preferred embodiments of the invention; and

Fig. 2 shows a suction lance of the apparatus shown in fig. 1, which suction lance comprises a valve unit with non-return valve and an overpressure valve;

Fig. 3A shows the function of the valve units in the normal suction situation during operation of the apparatus;

Fig. 3B shows the non-return valve function of the valve units;

Fig. 3C shows the overpressure valve function of the valve units; and

Fig. 4 shows an alternative design of the valve unit(s).

The illustration in Fig. 1 shows an apparatus 10 -a dosing apparatus, to be more precise- arranged for providing a liquid medium stored in a storage container 12 to a system (not shown) connected downstream the apparatus 10. The storage container 12 can be a canister, a barrel or another container. The apparatus 10 comprises the following main components: a pump 14, an extraction probe 16 (shown in Fig. 2) providing an inlet for liquid medium and a suction line 18 fluidically connecting the pump 14 with the extraction probe 16. The pressure side of the pump 14 is connectable with the system to be supplied with the liquid medium via a feeding line 20. The pump 14 therefore is a pump for pumping the liquid medium from the storage container 12 to the system, especially a dosing pump. The pump 14 of the apparatus 10 shown here is a reciprocating pump, or more precisely a diaphragm pump. The apparatus 10 further comprises a first valve unit 22 located in a first section 24 of the suction line 18 at the pump side (of the suction line 18) and a suction lance 26. This suction lance 26 forms the extraction probe 16 and a second section 28 of the suction line 18 at the extraction probe side (of the suction line 18). Further on, the suction lance 26 comprises a second valve unit 30 located in the second section 28 of the suction line 18. The apparatus 10 shown in fig. 1 is mounted in a rack and further comprises a flowmeter 32 located in a third section 34 of the suction line 18 between the first and the second section 24, 28.

On the left side of fig. 2 the suction lance 26 is shown in a side view. The lower part of the suction lance 26 is the extraction probe 16 for extracting the liquid medium out of the storage container 12. The extraction probe 16 is adapted for being inserted into the storage container 12. The upper part of the suction lance 26 forms the second section 28 of the suction line 18 ending towards the third section 34 by means of an elbow 36.

On the right side of fig. 2 the second valve unit 30 located in the second section 28 of the suction line 18 is shown in a sectional view. The second valve unit 30 has the same structure like the (first) valve unit 22. Each of these valve units 22, 30 comprises a non-return valve 38 and an overpressure valve 40. While the overpressure valve 40 of the valve unit 22 opens towards the extraction probe side of the suction line 18 in case of a predefined overpressure the overpressure valve 40 of the second valve unit 30 opens towards the extraction probe 16 and the storage container 12 in case of a predefined overpressure. The non-return valve 38 and the overpressure valve 40 of the valve unit 22, 30 are arranged in line.

The second valve unit 30 (as well as the valve unit 22) comprises a locking body 42, a displaceably mounted support unit 44 for supporting the locking body 42, a counter pressure element 46, a first seal element 48 for sealing a passage A between the locking body 42 and the support unit 44 and a second seal element 50 for sealing a passage between the support unit 44 and a sleeve element 52. The locking body 42 is in the form of a ball (ball- shaped). Each of the seal elements 48, 50 is formed as a torus-shaped seal ring (O-ring). The first seal element 48 is located radially inside the second seal element with an axial shift. The locking body 42 is the locking element of the non-return valve 38 and the arrangement of the locking body 42 together with the support unit 44 is the locking element of the overpressure valve 40.

In the following the function of each of the valve units 22, 30 is demonstrated with the example of the valve unit 22.

Fig. 3A shows the function of the valve units 22, 30 in the normal suction situation during operation of the apparatus 10. In this situation the counter pressure element 46 (not shown in this fig.) holds the support unit 44 in a normal position in which the second sealing element 50 seals the passage between the outside of the support unit 44 and the inside of the sleeve element 52 provided by a housing 54 of the valve unit 22, which housing 54 encloses the other elements 42, 44, 46, 48, 50 of the valve unit 22. Due to the suction of the pump 14 (represented by the arrow 56 pointing in the direction of the pump) the locking body 42 is moved towards the pump 14 (lifted) and releases the passage A between the support unit 44 and the locking body 42 and liquid medium coming via the suction line 18 from the container 12 can be sucked in by the pump 14.

Fig. 3B shows the non-return valve function of the valve units 22, 30. In case of a pressure surges below a given limit (represented by a narrow arrow 58 pointing in the direction of the extraction probe/container) the counter pressure element 46 still holds the support unit 44 in the normal position in which the second sealing element 50 seals the passage between the outside of the support unit 44 and the inside of the sleeve element 52 provided by a housing 54 of the valve unit 22. Due to the pressure surges (represented by the arrow 58) the locking body 42 is pressed back into support unit 44 and the first seal element 48 seals the passage between the locking body 42 and the support unit 44. Consequently, the flow of liquid medium is completely blocked and comes to a standstill. The aforementioned pressure limit of a predefined overpressure can be, e.g., p = 5 bar. The pressure limit is given by the spring constant of the compression spring.

Fig. 3C shows the overpressure valve function of the valve units 22, 30. In case of a pressure surges above the given limit (represented by a broad arrow 58 pointing in the direction of the extraction probe/container) the locking body 42 is still pressed into support unit 44 and the first seal element 48 seals the passage between the locking body 42 and the support unit 44. In addition, the pressure given by the pressure surges is high enough to deform the counter pressure element 46. The arrangement of the support unit 44 and the locking body 42 pressed into the support unit 44 is now moved in opposite direction towards the extraction probe/container and releases the passage B between the support unit 44 and the sleeve element 52. At this point liquid medium coming from/via the pump 14 can be released via the passage B within the valve unit 22, the suction line 18 and the extraction probe 16 back to the container 12 (arrow 60).

Using the apparatus 10 shown in fig. 1 including the two valve units 22, 30 as well as the flowmeter 32 located in the suction line 18 between said two valve units 22, 30, it is possible to register onwards pressure pulses (in direction of arrow 56) as well as backwards pressure pulses (in direction of arrow 58). The flowmeter 32 can preferably be an Oval Gear Meter like the OGM PLUS distributed by ECOLAB. With this setup it is possible to detect an overflow directly in the suction line 18 (not like an undefined leakage in a sump). Further on it is possible to detect insufficient dosing size immediately and quantitatively. To process the signals (recurring on- and backward flow) an implementation in a control unit is desirable.

The use of the aforementioned apparatus 10 has the following advantages:

Safety for customer and equipment, e.g. low maximum pressures in pump heads and lines and no contact with unprotected backflow chemicals or other harmful liquid media.

Quality and process stability: New opportunity to detect backflow immediately with

OGM PLUS by the control unit.

Fig. 4 shows an alternative design of the valve unit 22. While the non-return valve 38 and the overpressure valve 40 of the valve units 22, 30 shown in figs. 2 and 3A-C are arranged in line (coaxially), the non-return valve(s) 38 and the overpressure valve 40 of the valve unit 22 shown in fig. 4 are arranged in parallel. One section of the main fluid path of the valve unit 22 is split into two parallel running fluid paths 62, 64. The first fluid path 62 comprises a serial arrangement of two non-return valves 38 and the second fluid path comprises the overpressure valve 40. Alternatively, the first fluid path 62 could comprise a single non-return valve 38.

With the embodiment of the valve unit 22, 30 shown in fig. 4 each of the valves (nonreturn valve(s) 38 and overpressure valve 40) has its own locking body 42 and a corresponding support unit 44. Each of the locking bodies 42 is in the form of a ball. In contrast to the valve unit 22, 30 shown in figs. 2 and 3A-C, the support units 44 of this embodiment do not need to be displaceably mounted support units 44. They can be fixed support units 44.

It should be noted that, as used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.