EP0338505A1

EP0338505A1 - Gear pump for forming and coveying air-liquid mixtures, designed for rapid cleaning without disassemly

Info

Publication number: EP0338505A1
Application number: EP89106918A
Authority: EP
Inventors: Ermes Polo Tacchia
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-18
Filing date: 1989-04-18
Publication date: 1989-10-25
Also published as: IT8845717A0; IT1225107B

Abstract

The present invention relates to a gear pump particularly useful for employ in an apparatus for the instantaneous preparation of whipped cream, for forming a mixture of air and liquid cream at an adjustible mixing rate, and for conveying this mixture. The pump has an air inlet port (7,8) downstream of the liquid inlet port (4) adjacent the path of the teeth of each of its gears, and an outlet port (14) for the mixture downstream of the camming sector of the gears of the pump. The air aspiration flowpath extents in part through adjustment means (9) operable to adjust the amount of the liquid intake of the pump.

Description

In the case of pumps actually employed in apparatus for the instantaneous preparation of whipped cream, the cleaning not only of the liquid intake conduit, but also of the air intake passages can only be carried out after the pump has been dismounted and the liquid cream has been drained from the refrigerated compartment of the apparatus. The pump forming the subject matter of the invention permits the intake conduits and passages for both of the media to be conveyed to be rapidly and effectively cleaned without requiring the pump to be dismounted and/or the liquid medium to be drained.
The pump is provided with externally operable means for adjusting the mixing rate of the liquid and gaseous phases within a range of adjustment between one limit state, in which only the liquid phase is taken in by the pump, and another limit state, in which only the gaseous phase is aspirated by the pump. This adjustment means forms part of the air intake passage of the pump. Inserted into this adjustment means in an axially and radially loose fit is a conduit for the intake of the liquid cream. By pouring small amounts of water or any suitable detergent liquid into a flared inlet opening of the adjustment means and simultaneously operating the pump, it is possible to rapidly clean the internal passages of the pump without having to drain the liquid cream from the refrigerated compartment of the apparatus and without having to aspirate the water or other liquid detergent from a separate vessel or reservoir.
Further characteristics and advantages of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawings, wherein:

fig. 1 shows a sectional view of a pump according to the invention, taken along the line B-B in fig. 2, and
fig. 2 shows a sectional view of the same pump taken along the line A-A in fig. 1.

With reference to the drawings, the pump illustrated therein is of the spur-gear pump type comprising a housing 1 having two spur gears 2 and 3 mounted therein. Housing 1 is formed with a liquid inlet port 4 and an air inlet passage 5 opening into a chamber 6. The latter communicates with two air intake ports 7 and 8 extending tangentially along the circumferential paths of the teeth of respective gears 2 and 3. Seated in housing 1 is a cylindrical adjustment element 9 adapted to be rotated about its axis for selectively varying the opening of liquid intake port 4 by means of its chamfered end portion 10. Inserted into cylindrical adjustment element 9 in a freely rotatable manner is an end portion of a liquid intake conduit 11. The pump is closed′ by a cover 12 suitably secured to housing 1, so that rotation of gears 2 and 3 in the direction indicated by respective arrows 13 causes the intake of liwuid through port 4 and or air through ports 7 and 8, and the outflow of a corresponding air-liquid mixture through an outlet port 14 and towards a mixing and dispensing device (not shown) secured to cover 12 and suitably connected to the pump. For adjusting the mixing rate of the two phases entering the pump, cylindrical adjustment element 9 is rotated for restricting the opening of liquid intake port 4 to a greater or lesser degree. When intake port 4 is completely obturated in this manner, the pump aspirates only air through intake ports 7 and 8. As shown in the drawings, intake ports 7 and 8 communicate with atmosphere through chamber 6, passage 5 and further passages 15 and 16 suitably formed in the lower portion of adjustment element 9, the latter terminating in a flared portion 17 above the level 18 of the liquid 19 to be aspirated. A number of annular seals 20, 21 22 and 23 is suitably disposed for keeping the two media to be pumped separate from one another.
By slightly retracting the liquid intake conduit 11 and pouring small amounts of water or other liquid detergents into flared end portion 17 of adjustment element 9 while the pump is in operation, it is possible to clean the internal passages of the pump. This cleaning operation can be carried out in a very short time without dismounting any components and without having to drain the liquid cream from the refrigerated compartment of the apparatus.

Claims

A gear pump for forming and conveying air-liquid mixtures, comprising a liquid intake port at an upstream position of the circumferential path of the gear teeth, an outlet port for the air-liquid mixture at a downstream position of the circumferential path of the gear teeth, and a tangential air intake port adjacent the circumferential paths of the teeth of each gear at a location between said liquid intake port and said mixture outlet port, and adjustable means for restricting or obturating said liquid intake port, characterized in that the air intake flowpath (5,6,15,16) esxtends at least in part through said adjustanble means (9) for restricting or obturating said liquid intake port (4).