US 3186551 A
Description (OCR text may contain errors)
June 1, 1965 A. DORNAUF 3,186,551
JET FUEL FILTERING, EMULSION BREAKING AND DRYING DEVICE Filed April 11, 1960 3 Sheets-Sheet l I-nvem'or Arnold 5,.
June 1, 1965 A. DORNAUF 3,186,551
JET FUEL FILTERING, EMULSION BREAKING AND DRYING DEVICE Filed April 11, 1960 3 Sheets-Sheet 2 Fig. 2
" ammi \\\\\I)\\\ 227mm024w? /X/ 78 Dornauf m. *knl June 1, 1965 A. DORNAUF JET FUEL FILTERING, EMULSION BREAKING AND DRYING DEVICE Filed April 11, 1960 3 Sheets-Sheet 3 Invehib A1- mMDwwQuf United States Patent J 2 Qairns. (oi. sis-24s This invention relates to a transfer device for mineral oils or other liquid hydrocarbons, particularly jet engine fuels, which comprises a chamber receiving the raw liquid, a surge and separating chamber, and a plurality of hollow cylindrical filter elements interconnecting the said two chambers, the said filter elements comprising filter layers of different pore Width.
A transfer device of the type indicated is intended to serve the function of breaking up any emulsion present in the liquid, usually a water-in-oil emulsion, of draining away the Water separated from the liquid, of dissipating any electrostatic charges that may have been produced in the supply line or in a pump or pumps arranged upstream of the device or in any other device used in handling the liquid, and of removing any dirt particles that may be present in the liquid. The present invention is particularly applicable to the drying and filtering of jet engine fuels. In the case of the drying function it is required that thefilter elements operate in a satisfactory manner even when a quantity of say 3,000 liters of solution per minute is passed through the device and when the fuel supplied to the device contains for example 3% water in the form of a Water-in-fuel emulsion. After its passage through the filter elements the liquid should not'contain more than 0.00025% water. For example, if the fuel is contaminated with rust or iron oxide, the grain size of about 50% of the particles being below 0.25 micron, and if the liquid supplied to the device contains an amount of dirt of about 75 milligrams per litre, the filtered fuel should not contain more than 0.75 milligram of dirt per litre. The transfer device is required to operate in this manner because modern jet engines are provided with control devices the parts of which are held within tolerance limits of less than 1 micron; if foreign matter or water tending to freeze at high altitudes were present in the fuel, such control devices would be caused to fail, this in turn resulting in failure of the jet engine.
The heretofore known transfer devices of the aforeindicated type have a drawback in that they will not Withstand the increasing pressure diiferential caused by the progressive accumulation of dirt, the result being that these known devices will either be destroyed or tend to form channels through which the emulsion contained in the liquid might pass without being separated into its constituents.
In a transfer device of the aforementioned general type, the said drawbacks are eliminated according to the invention by the provision of a filter layer which is the first one to be passed by the liquid to be filtered and which has pores the size of which is approximately fifty to one hundred and fifty times, and preferably one hundred times, greater than the size of the pores corresponding to the size of the maximum particles allowed to be passed by the filter.- It has been found that in the case of a different pore size, for example in the case of pores being twenty times as large as said size, the filtering action is very good indeed, but that the pores will be clogged very quickly so that the dirt collecting capacity of the filter layer will be exhausted within a very short period. On the other hand, if the size of the pores is three hundred times as large as said size or if it is even greater, the layers Patented dune l, 1965 SD [an of the filter medium which usually have a thickness of about 10 mm. inch) will pass an excessive amount of dirt, the result being premature clogging of the second filter layer. According to the inventiomthe required pore size is provided by a suitable selection of the diameter of the filter medium, by the use of dilferent degrees of compression of the individual filter layers and/or different degrees of concentration of the impregnating medium.
According to a further feature of the invention, the said first filter layer is installed in such a manner as to be subjected to pre-stressing forces approximately corresponding to the proof pressure the said layer has to withstand. The pie-stressing forces are applied in one embodiment of the invention by means of an external wire helix wound about the respective filter layer. In another embodiment of the invention a filter layer having a larger initial diameter is introduced into a perforated sheet metal tube of smaller diameter, this being done with the aid of a tapered guide member. While it is possible to impart a relatively high strength to the first filter layer by impregnating and curing it, the hazard remains in applications of the type considered here that, where the filter element is clogged with dirt and where pressure surges occur, the fibres of the filter medium which are only bonded together by a synthetic plastic material will be torn apart so that channels are formed through which the accumulated foreign matter will suddenly pass into the discharge line for the filtered fluid. It will be understood that any increase in the amount of dirt collected will result in an increase in the pressure differential required to force the liquid through the filter elements at a rate of say to 200 litres per minute. During normal operation, this pressure differential will increase up to 1.5 kgs. per square centimeter (21 pounds per square inch), and during application of the proof pressure will increase up to between 5 and 7 lrgs. per square centimeter (71 to 100 pounds. per square inch). According to the invention, the said wire helix and the perforated sheet metal tube serve to support the first filter layer and to prevent partial or total destruction by the said high unit pressure.
Furthermore, the invention provides for the filter elements to be closed at their end faces by metallic cupshaped disc members which are electrically connected to the wire helix or the perforated sheet metal tube, respectively, and, where applicable, with other metallic supporting members. Conveniently the partitioning wall separating the chamber for the raw fluid from the quieting chamber is made of metal and is earthed. This makes it possible to dissipate any electrostatic charges carried by the hydrocarbon as well as any electric charge introduced by the emulsion.
Other objects and. features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating certain preferred embodiments of the invention, wherein:
FIG. 1 is a diagrammatic longitudinal sectional elevation of the entire transfer device of the invention;
FIGS. 2 and 3 respectively show in a longitudinal sectional view and a transverse sectional view an embodi men-t of the filter element of the invention;
FIGS. 4 and 5 resemble FIGS. 2 and 3, respectively, and illustrate another embodiment of the filter element of the invention.
Referring now more in particular to the drawings, FIG. 1 shows a transfer device generally designated 1 and comprising a chamber 2 for the raw liquid into which the raw liquid is'introduced through an inlet 3, the liquid uniformly distributing itself in the chamber 2, a quieting and separating chamber 4- having a drain 5 for thewithdrawal of the Water collecting in the lower portion of the As shown in FIGS. 2 and 3, each filter element 1% comprises an inner perforated sheet metal tube 11 serving as a support for the filter element proper; the tube 11 is surrounded by a first filter layer 12 consisting of plasticresin bonded mineral fibers and having pores of a size one hundred times greater than the maximum size of the particles allowed to pass the filter. The filter layer 12 is supported on its outside by a prestressed wire helix 13,,
the amount of prestress applied by means of the wire helix being'a function of the unit pressure to be applied to the outer filter layer 14, the said unit pressure being selected quiredto withstand. The filter layer 14 surrounding the wire helix 13 consists of'finephenolic resin bonded glass fibers and serves to break the emulsion and to produce a coagulating effect as explained below. The layer 14 is. retainedin position by several Wound layers of open-mesh has a high strength and the poresof this layer are one hundred times'larger than the maximum size of the particles allowed to pass the filter. 'The'inner surface of the glass fiber tube 23 is provided with longitudinal grooves 24to increase the exposed surface area and thus to inrprove the dirt retaining capacityof the tube. As an alternative, the glass fiber tube 23mav be of star-like shape in cross-section. The wire helix described in connection With'FlGS. 2 and 3 may be applied directly on the outside of the glass fiber tube to provide the required amount of prestress. However, in the case of the embodiment of FIGS. 4 and 5,.tl1e glass fiber'tube 23 is surrounded by an inner perforated sheet metal cylinder '25.. The desired prestress is applied to the glass fiber tube 23 by giving it a larger initial outside diameter and by using a tapered guide member to'introduce' it into the inner perforated sheetmetal'cylinder. 25whose inner diameter is .20 to approximate the proof pressure the said'layer is re- 9 smaller than the outer'diameter of the cylinder or tube 23.
The polymerization of the agent-servingto bond the glass fibers together is carried out after the glassfiber tube has 7 been introduced into the perforated sheet'metal cylinder.
. break up the emulsion.
burlap 15 and by an outer perforated sheet metal cylinder d-er 16. The disc members 17, 18 are adhered to the cylinder and filter bodies by means of a gasoline.- .(petrol-) and Water-resistant adhesive 19 preventing the occurrence of channelling effects and thus preventing the passage of any emulsion.
The transfer device of the invention operates as follows: The liquid mixture introduced into the device through the inlet 3 is uniformly distributed throughout the chamoer 2 for the raw liquid and then flows into the central chambers 20 of the various filter elements in which the water-in-oil emulsion is broken up, the fine water droplets coagulatin into larger drops, the electrostatic charge being dissipated, and the foreign matter being retained. The large water drops emerging from the filter elements will quickly settle towards the water sump provided in the lower portion of the quieting and settling chamber 4 whence the water may be drained through the drain 5. Any air or gases separated from the liquid will rise towards the upper portion of the chamber 4 and are exhausted via the vent 6. The liquid hydrocarbon that has thus been freed of its water content and its electrostatic charge is withdrawn by way of the discharge pipe 7.
The dissipation of the electric charges'absorbed by the metallic parts of the filter elements is efiected both" directly through themetallic partitioning Wall 8 separating the chambers 2 and 4, and indirectly by way of the spindles 21 serving to clamp the filter elements between annular members 22, or by way of guide rodsSd and members 31 supporting the filter elements and electrically connected to either the metallicdisc members 17, 18 or the outer perforated shell. and tube 16. The partitioning wall 8 is electrically connected to the housing of'the device which itself is grounded also.
FIGS. 4 and illustrate an alternativeembodiment of the invention in which the inner perforated supporting tube 11 of the embodiment of FIGS. 2 and 3 is replaced by a filter layer 23 consisting of coarse glassfibers of between and microns impregnated with a synthetic resin bonding agent such as a completely polymerized phenolic resin bonding agent; The said filter layer 23 The filter and emulsion-breaking layers, together Wound around the inner perforated sheet metal cylinder 25 is a glass fiber Web 26forming the layer serving to This layer Zdis surrounded'by another glass fiber web 27 serving to coagulate the fine water droplets. Both the glass fiberlayer 2d and the glass fiber layer 27 contain a layer 28 of an impregnated open-mesh fabric of the type used in bags intended for onions. The entire structure is held together by an outer perforated sheet metal cylinder 29. Otherwise the con-v struction of the filter element of FIGS. 4 and 5 is identical with that of the embodiment of FIGS. 2 and 3.
-What is claimed is: I
1. A filter and water separator comprising a vessel having an inlet and an outlet for passing liquidto be treated therethrough, a metal partition member in said vessel disposed between said inlet:.and outlet, a plurality of cartridges secured to said member and disposed to receive liquid from said inlet and to discharge 'it to said outlet,
said cartridges comprising a cylindrical perforated center tube, an annular filter layer made of plastic resin bonded mineral fibers surrounding said tube and in contact therewith having a thickness of approximately 10 mm. and a pore size of approximatelySO to times greater in size than the maximum particle size allowed to pass through the filter layer with filtering action being provided by the ltering effect of said pore size-acting serially over the distance of said thickness, a prestressed wire helix extending longitudinally the full length of "said filter layer and wrapped completely around the outer diameter of said layer and radially compressing said layer in an inward direction at a unit pressureiequal to the predetermined burst pressure of said layer, to prevent channeling in said layer, and a second annular layer Wrapped around .said helix and said first layer to coalesce water from liquid passed through said first layer, said second layer having a pore size ditferent than the pore size of said first layer.
2. The separator of claim 1 wherein means are provided for electricallygrounding said filter cartridges.
References Cited hythe Examiner UNITED STATES PATENTS 7 Re. 24,136 4/56 Marvel 210315 1,926,115 9/33 Seymour. 2,138,256 11/38 Schuyler. 2,175,775 10/39 i Hunt 1. 210- 458 2,390,494 12/45 Briggs et al 210-323 2,548,400 4/51 Shepard -s 210-323 2,609,932 9/52,. vFricke. 2,911,101 11/59 Robinson 210458 REUBEN FRIEDMAN, Primary Examiner.
HERBERT L. MARTIN, CHARLESSUKALO,