GB2097927A - Liquid level indication - Google Patents

Abstract

Apparatus (10) for separating water from fuel includes an electrical water level indicating device (31) suspended with a deflecting shield (16) from a cover element (11). The device (31) comprises a reed switch (35) cooperating with a float (38). Liquid enters the apparatus through inlet (12) and impinges on the shield (16). Fuel leaves through outlet (13) and separated water remains in the container (15). <IMAGE>

Description

SPECIFICATiON An apparatus for purifying fuel comprising an electrical water level indicating device State of the art The invention originates from an apparatus for purifying fuel comprising an electrical water level indicating device according to the preamble to the main claim, Such an apparatus is already known from German OS 3 009 899 in which a water storage space is formed in a housing below a filter element. At the base of the housing a relatively large opening is located into which is screwed a plug in which is arranged a water discharge device and a pulse generator for the water level indicating device. Moreover, a float is guided on a rod-like component of the pulse generator. The disadvantage with this apparatus is that, as a result of the large volume of the filter insert, little room remains for the water storage space.

Furthermore, the housing of the apparatus must have a relatively large opening in order to accommodate the plug provided with its additional devices. Thus, an already provided housing cannot be used with this apparatus. A further disadvantage is that, in this case, an automatically operating throttle device is provided which prevents a discharge of fuel from the filter during the discharge of the water collected in the water storage space. In many cases, it can be a disadvantage in practice that the electrical connecting cables lead into the housing of the purifier from below and are thus quite inaccessible with unfavourable constructional arrangements of the apparatus. Furthermore, it is unfavourable that, in this instance, parts of the water level indicating device are arranged on a component which must often be exchanged, namely an exchangeable filter.Thus, the danger of damage to the water level indicating device is relatively great. Because of the guiding of the float actuating the electrical switch on a component fixed to the plug, the volume of the float must be maintained relatively small. Because of this, the robustness and accuracy of the water level indicating device can suffer.

Advantages of the invention As opposed to this, the apparatus in accordance with the invention for purifying fuel provided with an electrical water level indicating device comprising the characterising features of the main claim has the advantage that a larger storage volume for water is possible with a more simple construction. With it, existing components can be continued to be used and in addition a central opening for the introduction of the pulse generator into the cover element is provided in any case. Furthermore, it is then an advantage for the water level indicating device to be arranged on a unit which need not be continually exchanged. The danger of damage, especially to the pulse generator, is completely prevented.In addition, it is frequently an advantage when the electrical connecting cables lead into the apparatus from above and are thus easily accessible. Furthermore, by arranging the pulse generator in the cover element, an additional device can be provided at the base of the housing in a dimple manner.

Advantageous further developments and improvements of the apparatus set forth in the main claim are made possible by the measures set forth in the sub-claims. A construction according to claim 2 is particularly advantageous when an automatic throttle device is provided at the base of the housing and which, after the discharge of water, throttles or prevents the escape of fuel. The efficiency of the apparatus during the separation of water can be substantially increased by the arrangement according to claim 3. An arrangement according to claims 4 to 6 provides a more simple and operationally reliable construction whereby the purification remains fully functional even with a slightly inclined position.An extremely advantageous cheap construction is produced in accordance with claim 7 since, in this case, a single float undertakes two functions namely the function of actuating the switch and of throttling during the discharge of water. Especially preferable arrangements may be produced according to claims 8 to 11 which, above all, provide a simple cheap construction and enable a more reliable sealing after the discharge of water.

Under unfavourable operating conditions, the problem can arise that the material of which the float consists expands and could partially influence the operation of the apparatus. Above all, this applies when particular types of fuel are to be purified, during which operation relatively high temperatures occur and the plastics of the float swells. A particularly advantageous arrangement for solving this problem is provided by claim 12 wherein the apparatus for purifying remains fully functional even under such unfavourable operating conditions. Moreover, seizing of the float and additional friction of the float is above ail prevented in that the floats in particular form only a single sealing location between a water discharge union and the water storage space. An advantageous assembly of the apparatus may be achieved by the arrangement according to claim 13.With the aid of the float, a more reliable sealing after the discharge of the water may be achieved with the arrangement of a flat seating valve in the water discharge apparatus according to claim 14. Further advantageous arrangements are provided by the other claims and the description as well as the drawing.

Drawing Three embodiments of the invention are illustrated in the drawing and are described in detail in the following specification. Figures 1 and 2 show longitudinal sections through a first and second embodiment and Figure 3 is a partial section through a third embodiment.

Description of the embodiments Figure 1 shows an apparatus 10 for purifying fuel comprising an electrical water level indicating device. The apparatus 10 has a cover element 11 in which are formed a supply union 12 and a discharge union 13. Furthermore, the cover element 11, has a centrally arranged connecting union 14. A cup-like housing 15 is fixed to the cover element 11. A conical deflecting shield 1 6 which is fixed by means of its inner edge 17 to the connecting union 14, is arranged inside the housing 1 5 in its upper region.By means of its outer free edge 1 8, the deflecting shield 1 6 forms a narrow annular gap 1 9 between the deflecting shield 1 6 and the inner wall of the housing 15 and which is arranged between the supply union 12 and the discharge union 13. A cup-like projection 22 which receives an insert portion 23 is located at the bottom 21 of the housing 1 5. A water discharge device 24 is tightly screwed into the housing 15 with the aid of the insert portion 23.

The insert portion 23 forms a valve seat 25 inside the housing 1 5 with which is associated a valve cone 26 of a throttle float 27. The latter is formed as a substantially flat disc and has a specific gravity which, on the one hand, is higher than that of the fuel to be purified and on the other hand, is lower than that of water. A multi-armed guiding portion 28 inserted in the housing 1 5 guides the throttle float 27 in a radial direction and also limits its movement in an axial direction. The lower free end 32 of a pulse generator 31 engages the radially extending webs 29 of the guide portion 28. The pulse generator 31 consists essentially of a rod-like component 33 the upper end 34 of which formed as a threaded plug is sealingly and tightly screwed into the central connecting union 14.The component 33 consists of plastics material and in its interior accommodates a reed switch 35 the electrical connections 36 to which arrive through the upper end 34. In this way, the reed switch 1 5 is located only slightly below a plane which is formed by the outer edge 18 of the deflecting shield 16. An upper abutment 37 for an indicator float 38 is formed on the component 33 in the vicinity of the plane last referred to. The annular float 38 is slidingly guided on the rod-like component 33 wherein its upper end position is limited by the upper abutment 37 and its lower end position is limited by the end 32 which likewise serves as an abutment. The indicator float 38 accommodates an annular permanent magnet 39 with the aid of which the reed switch 35 is actuated.Moreover, the specific gravity of the indicator float 38 is so selected that it sinks in the fuel to be purified but floats in water. The diameter of the rod-like component 33 in the region between the upper end and the lower abutment 37 is made small enough for communication to be provided between the space in the housing 1 5 beneath the deflecting shield 1 6 and the discharge connection 13 through the central connecting union 14.

Thus, the pulse generator 31 forms part of a water level indicating device 41 which is connected to an alarm device (not shown in detail) The method of operation of the apparatus 10 for purifying fuel is described as follows: the fuel to be purified flows through the supply union 12 into the interior of the housing 1 5. The incoming fuel is guided through the narrow annular gap 1 9 by the deflecting shield 1 6 whereby the flow accelerates and the water included in the fuel is separated as a result of the action of gravity.

Downstream of the annular gap 19, the fuel is reversed and flow upwards into the space beneath the deflecting shield 1 6 and then through the central connecting union 14 to the discharge union 13. Because of its higher specific gravity, the separated water sinks downwards and is collected in the water storage space in the housing 1 5. When the water level of the water collecting on the bottom 21 reaches the throttle float 27 it entrains the latter upwards until the throttle float 27 abuts against the webs 29 of the guide portion 28. If the water level in the housing 1 5 rises still further then the indicator float 38 begins to float in the water and rises away from the end 32. In so doing, its permanent magnet 39 is located substantially of the level of the water.

The indicator float 38 is so guided on the rod-like component 33 with clearance that the float cannot tilt and the least possible friction occurs.

Finally, when the water level and with it also the permanent magnet 39 reaches the level of the reeds in the reed switch 35 then the latter releases a pulse which is transmitted through the connections 36 to an indicating device (not shown in detail). An operator can read from the latter that the maximal water level has been reached or exceeded. After reaching or exceeding the maximal water level, the operator initiates the water discharge procedure by opening the screw on the water discharge device 24. In so doing, water flows out of the water storage space in the housing 1 5 through the insert portion 25 and the water discharge device 24 to the outside. The water level then sinks in the housing 1 5 whereby the indicator float 38 finally rests on the end 32 serving as an abutment.On further lowering of the water level, the throttle float 27 also sinks and its valve cone 26 approaches the valve seat 25 on the insert portion 23. After the greater part of the water collected in the housing 1 5 has discharged to the outside, the valve cone 26 throttles the discharging pressure medium at the end of this operation and finally rests completely on the valve seat 25 in order to prevent a discharge of fuel from the interior of the housing. In so doing, the guide portion 28 provides a perfect guiding of the throttle float 27 so that, even with a slightly inclined position of the apparatus 10 or with an oscillating water level, an automatic throttling or a blocking at the end of the water discharge operation is achieved and an escape of fuel is completely prevented. When the indicator float 38 engages the end 32 the warning signal produced at the indicator device is switched off since the reed switch 35 is not actuated.

In this way, a large volume of water can be stored in the housing 1 5 with the apparatus 10.

Also, the pulse generator 31 is incorporated in the cover element 1 3 from above in an advantageous manner so that the electrical connections 36 are easily accessible. Because of this arrangement of the pulse generator 31 in the apparatus 10, an automatic throttling device for the water discharge operation can be provided without difficulty at the bottom 21 of the housing 1 5. An exchange of components such as is required with a filter is not necessary with this apparatus 10 so that continual removal and replacement of the pulse generator is not necessary either. On the other hand, the pulse generator 31 is of relatively cheap construction and can also be so designed that it can be easily exchanged if the read switch 35 becomes defective.

Figure 2 shows an apparatus 50 as a second embodiment which differs from the apparatus 10 according to Figure 1 as follows, wherein. like references are used for like parts: a first annular screen 51 is arranged at the free edge 1 8 of the deflecting shield 1 6 and then separates the water storage space 52 proper in the housing 1 5 from the space beneath the deflecting shield 1 6. The screen 51 consists of a fine mesh water repellent material and thus substantially increases the efficiency of the water separation. Again the pulse generator 31 has a tubular component 53 which accommodates the reed switch 35 together with its connections 36, which are cast therein, in a blind bore 54 opening towards the outside.The component 53 is made just long enough for the reed switch 35 to still be located beneath the screen 51. At its free end 55 projecting into the water storage space 52, the component 53 is made conical. A single float 56 which undertakes both the function of a throttle float and also that of an indicator float is arranged in the water storage space 52. The float 56 has a central hub 57 which is in communication with an outer guide ring 59 through flat webs 58. A recess 61 in which the annular permanent magnet 39 is inserted is formed in the hub 57 coaxial to the pulse generator 31 and open towards the latter.

At the end of the hub 57 associated with the insert portion 23, the hub carries a valve cone 62 which cooperates with the valve seat 25 on the insert portion 23. In the region of the valve cone 62, a throttle bore 63 leads from the recess 61 into the water storage space 1 5. In order to prevent tilting of the float 56 during operation, the guide ring 59 is made relatively high. Moreover, the float 56 is so designed that it floats on the water but sinks in the fuel so that the position in height of the float and thus of the permanent magnet 39 is a measure of the position of the water level.

The method of operation of the apparatus 50 corresponds substantially to that of the apparatus 10 wherein the functions of the indicator float and of the throttle float are undertaken by the single float 56. When, due to a rising water level, the float 56 reaches the pulse generator 31, it is additionally centred and guided by the conical end 55 entering the recess 61. In addition, with the aid of the throttle bore 63, a limited damping effect may also be achieved thereby. With this construction, the float 56 can be made relatively large whereby a reliable seal can be achieved at the end of the water discharge. The apparatus 50 is particularly simple and cheap and thus advantageous due to the use of a single float for the two functions. Also, the guiding of the float 56 in the housing 1 5 produces a simple construction of the apparatus 50.In this case, the tubular component 53 of the pulse generator 31 can be made relatively short; also its construction facilitates an easy exchange of the pulse generator 31.

Figure 3 shows a portion of an apparatus 70 in the form of a third embodiment which differs from that according to Figure 2 as follows, wherein like references are used for like parts: the pulse generator 31 now has a substantially longer tubular component 71 the conical end 72 of which comes to rest at a slight distance from the insert portion 23. A flat seating surface 73 is formed on the insert portion 23. In the illustrated position, the centrally arranged sealing portion 75 of a throttle float 74 engages the said seating surface 73. From the sealing portion 75, webs 76 lead to a conical ring 77 which opens towards the deflecting shield 1 6. Additional external guide lugs 78 are arranged on the ring 77. The conical ring 77 comprises a supporting surface 79 formed by the webs 76 and from which a centering recess 81 projects into the sealing portion 75.

The position of the throttle float 74 relatively to the housing 1 5 is centred by the conical end 72 of the pulse generator 31 projecting into the recess 81. The distance between the end 72 and the inner end of the recess 81 is great enough for the throttle float 74 to be able to perform a sufficient opening stroke. The outer diameter of the throttle float 74 is chosen considerably smaller than the inner diameter of the housing 1 5 so that even under extreme operating conditions, no seizing can occur between the float and the housing. A single float 82 engages the supporting surface 79 and its outer diameter is chosen smaller than the diameter of the supporting surface 79. The indicator float 82 has a central guide bore 83 in which the annular permanent magnet 39 is also inserted.By means of its cylindrical section, the component 71 projects into the said guide bore 83 and thus takes care of a perfect guiding of the float 82. Moreover, a discharge throttle 84 is incorporated in the insert portion.

The method of operation of the apparatus 70 corresponds to that of the apparatus 10 according to Figure 1 insofar as the throttle float 74 can perform a stroke limited by mechanical abutments and the indicator float 82 is guided by the pulse generator 31 during its greater stroke.

The difference is however, that the throttle float 74 is no longer guided in a housing or a part fixed to the housing but simply and solely by the pulse generator 31. In this way, the apparatus 70 operates more reliably even under extreme operating conditions. Thus, with some fuels and at high temperatures, the plastics of the floats 74 and 82 can swell considerably and that can lead to a corresponding widening of their outer diameter without that leading to a seizing of the floats in the housing 1 5. Furthermore, there is a particular advantage in that, despite the guiding of both floats by the pulse generator 31, only a single sealing location is provided between the water separating space 52 and the water discharge device 24.Furthermore, it is particularly advantageous that towards the end of the water discharge, the indicator float 82 rests on the supporting surface 79 and thus forces the sealing portion 75 of the throttle float 74 additionally onto the flat seat 73 so as to guarantee a gooc; seal. A more reliable and good seal is further improved by the formation in the form of a flat seating valve. Moreover, it is of advantage that, due to its construction, the float permits an easy assembly. Thus, before fixing the cover element on the housing 15, the throttle float 74 can easily be inserted in the housing 1 5 and the indicator float 82 be inserted thereafter whereby the latter is itself centred in the throttle float 74 by the conical ring 77.After mounting the cover element on the housing 15, the pulse generator 31 can be easily incorporated whereby its conical end 72 enters the recess 81 through the guide bore 83 and centres both floats 74, 82.

Due to the discharge throttle 84, the sealing portion 75 of the throttle float 74 is prevented from engaging the seating surface 73 prematurely and blocking the water discharge, due to the suction effect. Emptying of the water can then take place with advantage by a running fuel pump and above all no ventilation of the apparatus 70 is required. Thus, a false operation is prevented; no benzene can be ejected and lead to the danger of an expiosion as a result of the pressure acting in a pressure accumulator.

Variations in the illustrated embodiments are of course possible without departing from the concept of the invention. Thus, a float of sheet steel which is formed as a hollow member can be provided instead of the one part float 56 according to Figure 2 made of plastics. With it a greater buoyancy and a greater weight on the valve seat during water discharge may be achieved whereby the suction effect is thoroughtly removed. If necessary, with this arrangement, aggressive fuels can be conveyed through the water separator.

Claims (20)

Claims

1. Apparatus for purifying fuel comprising an electrical water level indicating device and a cover element in which connections for the supply and discharge of fuel are formed and comprising a housing arranged beneath the cover element which has a water storage space in which is arranged a float provided with a permanent magnet associated with a water level indicator and which controls a pulse generator in accordance with the water level which has an electrical switch in a rod-like component, characterised in that, a conical deflecting shield, which with its free outer edge forms an annular gap arranged between the supply and the discharge, is arranged in the interior of the housing in its upper part and that the pulse generator is arranged in the cover element coaxial with respect to the longitudinal axis of the apparatus and its rod-like component passes through the deflecting shield and carries the switch beneath the deflecting shield.

2. Apparatus according to claim 1, characterised in that, a water discharge device which has a float throttling the water discharge, is arranged at the bottom of the housing.

3. Apparatus according to claim 1 or 2, characterised in that, a water repellent screen which is fixed to the free outer edge of the deflecting shield and through which the pulse generator projects, is arranged between the annular gap and the discharge.

4. Apparatus according to one of claims 1 to 3, characterised in that, the float associated with the pulse generator and serving as an indicator is guided on the rod-like component

5. Apparatus according to one of claims 2 to 4, characterised in that, a guide portion in which the throttling float is guided is arranged in the housing in the vicinity of the bottom.

6. Apparatus according to claim 5, characterised in that, the rod-like component retains the guide portion in engagement with the base of the housing.

7. Apparatus according to claim 2 or 3, characterised in that, a single float is provided for the functions of actuating the switch and throttling during the discharge of water.

S. Apparatus according to claim 7, chai-acLerised in that, the float is guided in the housing.

9. Apparatus according to claim 7 or 8, characterised in that, the rod-like component projects substantially beyond the deflecting shield by the length of the switch and its free end is associated with a recess in the float centering the float and that the said recess accommodates the magnet actuating the switch.

1 0. Apparatus according to claim 9, characterised in that, the float has a valve cone cooperating with the water discharge union.

11. Apparatus according to claim 9 or 10, characterised in that, the float is formed as a substantially symmetrical body of revolution which has in particular a recess receiving the free end of the pulse generator together with the switch.

12. Apparatus according to one of claim 2 to 4, characterised in that, the rnd-lilce component terminates at a slight distance from the water discharge union and its free end projects into a centering recess in the throttling float which is arranged with its sealing portion between the water discharge union and the end and which has a supporting surface for the float actuating the switch, the float being guided on the rod-like component by means of a central guide bore.

13. Apparatus according to claim 12, characterised in that, means centering the indicator float are arranged on the throttle float.

14. Apparatus according to claim 12 or 13, characterised in that, together with the water discharge union, the sealing portion forms a flat seating valve.

1 5. Apparatus according to one of claims 12 to 14, characterised in that, the distance between the inner wall of the housing and the outer diameter of the float is greater than the corresponding expansion of the float due to swelling of the material forming the float, especially plastics, during operation.

1 6. Apparatus according to one of claims 12 to 15, characterised in that, when the float engages the water discharge union the free end projects into the centering recess wherein a distance corresponding to the opening stroke of the throttling float is located between the two parts.

1 7. Apparatus according to one of claims 1 to 16, characterised in that the switch in the pulse generator is arranged in a blind bore in the component sealed from the interior of the housing and opening towards the outside.

1 8. Apparatus according to one of claims 2 to 4, characterised in that, the throttle float and the indicator float are guided only by the component of the pulse generator and control a single sealing location between the water storage space and the water discharge union.

19. Apparatus according to one of claims 2 to 18, characterised in that, the water discharge device has a discharge throttle.

20. Apparatus for purifying fuel, substantially as herein described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.