Abstract
A foam generator includes a foam generation chamber which contains or consists of a porous filling material and which has at least one inlet for supplying a liquid and a gas, and an outlet for discharging the foam generated in the foam generation chamber. The mean pore diameter of a cross-sectional area of the filling material decreases from the inlet to the outlet continuously or discretely.
Claims
1. A foam generator comprising a foam generation chamber which comprises a porous filling material and which has at least one inlet for supplying a liquid and a gas as well as an outlet for discharging the foam generated in the foam generation chamber, wherein the mean pore diameter of a cross-sectional area of the filling material decreases from the inlet to the outlet continuously or discretely, wherein the filling material includes knitted fibers, and wherein the filling material consists of plural portions arranged directly in series, substantially without any spacing, the cross-sectional areas of which differ by their mean pore diameter.
2. (canceled)
3. The foam generator according to claim 1, wherein the pores of a cross-sectional area of the filling material are substantially equal.
4. The foam generator according to claim 1, wherein the porosity of the filling material decreases continuously and/or discretely from the inlet to the outlet.
5. The foam generator according to claim 1, wherein the filling material includes particles.
6. The foam generator according to claim 5, wherein the mean diameter of the particles decreases continuously and/or discretely from the inlet to the outlet.
7. The foam generator according to claim 5, wherein the particles are beads and are made from glass.
8. (canceled)
9. The foam generator according to claim 1, wherein a diaphragm is arranged upstream of the filling material.
10. A vehicle treatment device comprising a foam generator according to claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0033] Hereinafter, the invention will be illustrated by way of drawing figures, wherein:
[0034] FIG. 1 shows a longitudinal section across a first example embodiment of a foam generator according to the invention;
[0035] FIG. 2 shows a section across the filling material of a foam generator according to the invention of the first example embodiment along the cutting line II of FIG. 1;
[0036] FIG. 3 shows a section across the filling material of a foam generator according to the invention of the first example embodiment along the cutting line III of FIG. 1;
[0037] FIG. 4 shows a section across the filling material of a foam generator according to the invention of the first example embodiment along the cutting line IV of FIG. 1;
[0038] FIG. 5 shows a graphical representation of the mean pore diameter over the length of the foam generation chamber of a foam generator according to the invention of the first example embodiment;
[0039] FIG. 6 shows a longitudinal section across a second example embodiment of a foam generator according to the invention;
[0040] FIG. 7 shows a section across the filling material of a foam generator according to the invention of the second example embodiment along the cutting line VII of FIG. 6;
[0041] FIG. 8 shows a section across the filling material of a foam generator according to the invention of the second example embodiment along the cutting line VIII of FIG. 6;
[0042] FIG. 9 shows a section across the filling material of a foam generator according to the invention of the second example embodiment along the cutting line IX of FIG. 6; and
[0043] FIG. 10 shows a graphical representation of the mean pore diameter over the length of the foam generation chamber of a foam generator according to the invention of the second embodiment.
[0044] The figures are merely schematic and serve exclusively for the comprehension of the invention. Like elements are provided with like reference numerals. The features of the individual example embodiments are interchangeable.
DETAILED DESCRIPTION
[0045] FIG. 1 illustrates a longitudinal section across a first example embodiment of a foam generator 1 according to the invention. There is evident a foam generator 1 which includes a foam generation chamber 2 of cylindrical or prism-shaped structure, for example, with a porous filling material 3. Beneath the foam generation chamber 2 a diaphragm 4 is arranged. Through an inlet 5 arranged at the lower portion of the foam generator 1 a foamable liquid component which may consist of or contains a detergent diluted with (tap) water is fed into the foam generator 1. Through an inflow portion 6 arranged at the lower portion of the foam generator 1 a gaseous component, such as, for example, air or compressed air, is introduced to the foam generator 1. The supply of a liquid component, hereinafter referred to as liquid, and a gaseous component, hereinafter referred to as gas, may be performed by applying pressure, for example by a pump. The liquid and the gas supplied to the foam generator 1 flow through the diaphragm 4 resulting in pre-mixing of the liquid and the gas, before the mixture of liquid and gas, hereinafter referred to as mixture, flows into the foam generation chamber 2. The outermost surface of the filling material 3 facing the diaphragm 4 may also be referred to as inflow point for the mixture into the foam generation chamber 2. In the upper portion of the foam generator 1 and above the foam generation chamber 2, an outlet 7 or, resp., a foam outflow opening is arranged. The outermost surface of the filling material 3 facing the outlet 7 may also be referred to as outflow point for the mixture from the foam generation chamber 2. The foam generation chamber 2 is equipped with a filling material 3 whose mean pore diameter P.sub.m narrows in the direction of flow of the mixture over the axial length of the foam generation chamber 2. In said first example embodiment, the mean pore diameter P.sub.m of the filling material 3 is reduced continuously, viz. at any interval between the inflow point and the outflow point. When the mixture flows through the filling material 3 and, resp., through the pores of the filling material 3, the mixture is sheared and foam bubbles are formed whose diameter is decreasing over the axial length of the foam generation chamber 2 due to the continuous pore narrowing. The mean pore diameter P.sub.m of the filling material 3 is designed at the upper end of the foam generation chamber 2 such that the foam bubbles of the mixture are brought to a target diameter. At the outlet 7 of the foam generator 1 the mixture leaves the foam generator 1 in the form of a stable foam.
[0046] Each of FIGS. 2 to 4 illustrates a section across the filling material of the foam generator 1 of the first example embodiment along the cutting lines II to IV of FIG. 1. As is evident from FIGS. 2 to 4, the diameter of the pores 3a of the filling material 3 decreases from the inflow point in the direction of the outflow point. The pores 3a are surrounded by a fill matrix 3b and jointly form the filling material 3.
[0047] FIG. 5 illustrates a graphical representation of the mean pore diameter P.sub.m over the length L.sub.s of the foam generation chamber 2 of a foam generator 1 according to the invention of the first example embodiment. In this example embodiment, the mean pore diameter P.sub.m continuously decreases over the axial length L.sub.s of the foam generation chamber 2 from the inflow point to the outflow point. The position 0 conforms to the inflow point and the position L conforms to the outflow point at the foam generation chamber 2. The broken lines indicate the cross-sectional positions of the cross-sections of the filling material 3 shown in FIGS. 2 to 4 and indicated equally by broken lines in FIG. 1. The mean pore diameter P.sub.m at the position L conforms to a target diameter by which the foam bubbles of the mixture are brought to a target size.
[0048] FIG. 6 illustrates a longitudinal section across a second example embodiment of a foam generator 1 according to the invention. The second example embodiment resembles the first example embodiment as to the basic structure and differs from the first example embodiment to the effect that the foam generation chamber 2 has three portions each showing a different mean pore diameter P.sub.m. In said second example embodiment, the mean pore diameter P.sub.m is reduced gradually, viz. in (several) stages, over the axial length L.sub.s of the foam generation chamber 2 from the inflow point to the outflow point. The lower portion 31 of the filling material 3 has a large mean pore diameter P.sub.m, the mean portion 32 of the filling material 3 has a medium-sized mean pore diameter P.sub.m and the upper portion 33 of the filling material 3 has a small pore diameter P.sub.m. A medium-sized mean pore diameter P.sub.m is understood to be a mean pore diameter P.sub.m which is smaller than the mean pore diameter P.sub.m of the lower portion 31 and is larger than the mean pore diameter P.sub.m of the upper portion 33.
[0049] Each of FIGS. 7 to 9 shows a section across the filling material 3 of the foam generation chamber 2 in the individual portions 31 to 33 of the filling material 3. It is evident here that the diameter of the pores 3a of the filling material 3 decreases from the lower portion 31 to the upper portion 33.
[0050] In FIG. 10, the mean pore diameter P.sub.m is graphically represented over the length L.sub.s of the foam generation chamber 2 of the foam generator 1 of the second example embodiment. In this example embodiment, the mean pore diameter P.sub.m decreases in stages from the inflow point to the outflow point over the axial length L.sub.s of the foam generation chamber 2. The position 0 conforms to the inflow point and the position L conforms to the outflow point at the foam generation chamber 2. The broken lines indicate the cross-sectional positions of the cross-sections of the filling material 3 shown in FIGS. 7 to 9 and indicated equally by broken lines in FIG. 6 in the portions 31 to 33. The mean pore diameter P.sub.m at the position L conforms to a target diameter by which the foam bubbles of the mixture are brought to a target size.
