WO2015028592A1

WO2015028592A1 - Fluid flow control device

Info

Publication number: WO2015028592A1
Application number: PCT/EP2014/068349
Authority: WO
Inventors: Othmar Rymann
Original assignee: Norgren Ag
Priority date: 2013-08-30
Filing date: 2014-08-29
Publication date: 2015-03-05

Abstract

A gas regulating device (200), a control block (224) for regulating gas, and a method for operating the same are provided. The control block (224) includes an accumulator (204), a plurality of valves (206, 208, 210, 212), and a plurality of fine orifices (214, 216, 218, 220). The plurality of valves (206, 208, 210, 212) are in communication with the accumulator (204) and the plurality of fine orifices (214, 216, 218, 220). The gas regulating device includes an air compressor, a control block, and a fine filter. The air compressor is configured to provide compressed air to the fine filter via the control block. A reset valve (222) may be included in the control block (224).

Description

FLUID FLOW CONTROL DEVICE

TECHNICAL FIELD

The invention is related to the field of fluid flow control, and more particularly, to controlling a fluid flow rate.

BACKGROUND OF THE INVENTION

There is an ever increasing need for fluid control devices that are electronically controlled, inexpensive and reliable. In order for a fluid flow control device to be effective and efficient, it should be simple and easy to operate. In order for a fluid control device to be competitive in a market place, it should be compatible with inexpensive components and not require excessive resources to operate.

One application for a fluid control device is in generating milk froth, milk foam, or aerated milk for beverages such as coffee in bars and restaurants. Milk froth with uniform micro foam distributed throughout is highly desirable for coffee drinks and other beverages. Different beverages and/or customer preferences require different qualities of milk froth, however, ranging from creamy to dry in texture.

The traditional method of generating milk froth, which includes manually applying steam to a reservoir of milk, requires training and skill to perfect. The problem is further complicated by the fact that different amounts of milk froth are required to create different beverages tailored to different customer preferences. Restaurants and bars, which often rely on part time or student help, may have a difficult time finding workers who have the skills required to produce high quality milk froth for beverages using traditional manual steaming methods.

Other techniques for generating milk froth include the use of mechanical agitation devices to whisk ambient air into the milk. Mechanical agitation devices produce milk froth with gas bubbles having a wide range of sizes, however, including larger air bubbles, which are undesirable. In addition, the milk froth produced by mechanical agitation devices often fails to get mixed uniformly into the milk.

When supplied with compressed air, fine air filters can produce small bubbles that may be used to aerate a fluid, and can be ideal for milk froth production. In particular, passing compressed air through a fine filter at a mass flow rate ranging from 10-70 Nl/h at a pressure of 1.2 - 1.5 bar can generate excellent quality micro foam in milk. One way to supply compressed air to a fine filter is via a micro compressor including a variable delivery brushless motor. Brushless motors are expensive, however, and the results may be somewhat inconsistent due to a non-linear P-Q curve.

Other solutions for providing compressed air to a fine filter include the use of a small, plastic centrifugal compressor. Small centrifugal compressors have a maximum pressure of 0.7 bar with a runtime that is much longer than 500 ms, however. As such, plastic centrifugal compressors do not offer enough pressure, nor are they responsive enough for the application of generating milk froth.

A further solution for generating compressed air includes a hose pump. Hose pumps are not generally suitable for gasses, however. Hose pumps also provide a large pulsation of pressure that is undesirable for milk froth production.

Restaurants and bars could benefit from a machine that offers a number of electronically selectable milk froth settings, produces high quality micro foam, is easy to use, and provides repeatable results. What is needed, therefore, is an improved fluid flow control device that can provide compressed air at digitally selectable flow rates with relatively low levels of air pulsation into a fine air filter immersed in milk.

SUMMARY OF THE APPLICATION

A gas regulating device is provided. The gas regulating device includes an air compressor. The gas regulating device further includes a control block that receives compressed air. The control block includes an accumulator that is in communication with the air compressor. The control block further includes a plurality of valves that are in communication with the accumulator. The control block further includes a plurality of fine orifices, each respective fine orifice being in communication with a respective valve. The gas regulating device further includes a fine filter in communication with the plurality of fine orifices. The air compressor is configured to provide compressed air to the fine filter via the plurality of valves and the plurality of fine orifices.

A control block is provided. The control block may provide compressed air from an air compressor to a fine filter. The control block includes an accumulator in communication with the air compressor. The control block further includes a plurality of valves in communication with the accumulator. The control block further includes a plurality of fine orifices, each respective fine orifice being in communication with a respective valve.

A method for making milk foam is provided. The method for making milk foam includes including the step of filling an accumulator with compressed air from an air compressor. The method for making milk foam further includes the step of controlling the flow of compressed air from the accumulator to a fine filter by operating a plurality of valves, each valve of the plurality of valves in communication with a respective fine orifice. The method for making milk foam further includes the step of passing the compressed air into a milk flow via the fine filter.

ASPECTS

In a preferred embodiment, the air compressor is a micro compressor.

In a preferred embodiment, the air compressor provides a mass flow between 10- 70 Nl/h at a pressure of 1.2-1.5 bar to the control block.

In a preferred embodiment the gas regulating device further comprises an orifice plate including the plurality of fine orifices, wherein the plurality of fine orifices are laser-etched into the orifice plate.

In a preferred embodiment the gas regulating device, further comprises a reset valve in communication with the plurality of fine orifices and the fine filter.

In a preferred embodiment the fine filter is embedded in a conduit carrying a fluid.

In a preferred embodiment the plurality of valves are operable to provide an electronically configurable fluid flow through the plurality of fine orifices to the fine filter.

In a preferred embodiment the air compressor is a micro compressor.

In a preferred embodiment the air compressor provides a mass flow between 10- 70 Nl/h at a pressure of 1.2-1.5 bar.

In a preferred embodiment the control block further comprises an orifice plate including the plurality of fine orifices, wherein the plurality of orifices are laser-etched into the orifice plate.

In a preferred embodiment, the control block further comprises a reset valve in communication with the plurality of fine orifices and the fine filter. In a preferred embodiment, the method of claim 15, further comprises the step of venting the compressed air through a reset valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The same reference number represents the same element on all drawings. It should be understood that the drawings are not necessarily to scale.

FIG. 1 depicts a milk frothing system 100 in accordance with an embodiment of the application.

FIG. 2 depicts a gas regulating device 200 in accordance with an embodiment of the application.

FIG. 3 depicts a control block 324 in accordance with an embodiment of the application.

FIG. 4 depicts a control block 324 in accordance with an embodiment of the application.

FIG. 5 depicts a pressure chart 500 of a milk frothing cycle from an example milk frothing system in accordance with an embodiment of the application.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-5 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents.

FIG. 1 shows a milk frothing system 100 in accordance with an embodiment of the application. The milk frothing system 100 includes a milk conduit 102, compressed air 104, a fine filter 106, a cup 108, milk 110, milk froth 112, fine air streams 114, and a compressed air conduit 116.

Conduit 102 is a pipe or other fluid carrying device that carries milk 110 in FIG. 1. Conduit 102 carries milk 110 through a first and second 90-degree rounded bend, the conduit 102 creating a profile of a step. Between the bends, fine filter 106 diffuses fine air streams 114 into milk 110 to generate milk froth 112. In further embodiments, conduit 102 may be formed to be straight or to include any number of bends.

Fine filter 106 receives compressed air 104 via compressed air conduit 116, producing fine air streams 114 that diffuse into milk 110 to generate milk froth 112. In an embodiment, milk 110 may flow along the length of fine filter 108, fine filter 108 being coaxially aligned with conduit 102. Fine air streams 114 may diffuse sideways out of fine filter 106 to aerate milk 110. In an example embodiment, milk may flow around fine filter 106 in a 1 mm coaxial flow. In embodiments, varying the mass flow and pressure of gas through fine filter 106 may determine the properties of milk froth 112, which may include a texture that ranges from dry to creamy. In further

embodiments, varying the mass flow and pressure of gas through fine filter 106 may be varied to promote mixing between milk 110 and fine air streams 114.

Milk 110 entering conduit 102 may include any type of milk, cold or warmed. In embodiments, milk 110 may be any type of fluid for which aeration is desired, for a beverage, food, or any other application. Milk froth 112 exits conduit 102 into cup 108. In embodiments, any fluid container may be used in place of cup 108.

Compressed air 104 enters fine filter 106 from outside conduit 102 via a separate fluid conduit 116. Compressed air 104 may include ambient air, steam, or any other gas mixture known to those of skill in the art. Fluid conduit 116 may include any conduit formed to provide compressed air 104 to fine filter 106, as will be understood by those of skill in the art.

Compressed air 104 may be generated by any type of air compressor, including a micro compressor including a brushless motor, a centrifuge, a hose pump, or any other type of micro compressor. In embodiments, a low flow rate micro compressor may be well suited to provide compressed air 104 to fine filter 106. A low flow rate micro compressor may provide the advantages of being inexpensive and simple to operate with repeatable results. In embodiments, an oil and lubricant- free compressor may be used, which is ideally suited for food and beverage applications. One particular challenge to using a micro compressor to generate milk froth with a fine filter is that some micro compressors have relatively strong pulsation for their low flow rates due to the sinusoidal displacement of their pistons. Strong pulsation of compressed air is undesirable in the application of milk frothing. In order to create high quality froth milk, the pulsation of fluid must therefore be reduced.

FIG. 2 depicts a gas regulating system 200 in accordance with an embodiment of the application. Gas regulating system 200 incorporates an air compressor 202 and an air control block 224 to produce compressed air 104. Air control block 224 includes an accumulator 204, valves 206, 208, 210, and 212, fine orifices 214, 216, 218, and 220, and reset valve 222.

Compressor 202 provides compressed air, which is stored in accumulator 204. Compressor 202 can be any type of compressor capable of providing the desired amount of gas flow at the desired pressure to fine filter 106 to produce high quality micro foam. For example, it has been demonstrated that with some fine filters a fluid flow between 10-70 Nl/h at 1.2-1.5 bar may be desired. In an embodiment, compressor 202 is a low- flow rate micro compressor. For example, some micro compressors can provide a mass flow of 90 Nl/h at 1.5 bar.

Control block 224 further includes accumulator 204. Accumulator 204 helps to absorb and dampen pulsation from compressor 202 to valves 206, 208, 210, and 212.

Upon exiting accumulator 204, compressed air flows to valves 206, 208, 210, and 212. Each valve 206, 208, 210, and 212 is adjacent to a fine orifice 214, 216, 218, and 220 through which gas flow is regulated. For example valve 206 communicates with fine orifice 214, valve 208 communicates with 216, valve 210 communicates with 218, and valve 212 communicates with valve 220. Valves 206, 208, 210, and 212 are positioned to be in parallel with one another. In the representation of FIG. 2, valves 206, 208, 210, and 212 are 2 position, 2 port (2/2), solenoid valves that are spring biased into a closed position. When valves 206, 208, 210, and 212 are open, fluid may pass from accumulator 204 to fine orifices 214, 216, 218, 220. In the representation of FIG. 2, four valves 206, 208, 210, and 212 are depicted with adjacent fine orifices 214, 216, 218, 220. This is not meant to be limiting, however, as it is possible to include any number of valves. Each of valves 206, 208, 210, and 212 may be individually opened to control the flow of compressed air 104 to fine filter 106. The more valves and adjacent fine orifices that are included in milk frothing system 200, the greater the gradation of milk froth settings that it will be possible to produce. Fine orifices 214, 216, 218, 220 are adjacent to valves 206, 208, 210, and 212 respectively. The diameters of fine orifices 214, 216, 218, 220 may be the same or different, and may be formed to produce a range of fluid flow settings required to generate a variety of milk froth settings. Fine orifices 214, 216, 218, 220 may be used individually or in any combination to produce different flow rates. In addition to providing flow control, fine orifices 214, 216, 218, 220 also serve to dampen pulsation from compressor 202 at fine filter 106. In embodiments, the fine orifices 214, 216, 218, 220 are fabricated precisely to produce the best quality micro foam. For example, tolerances of ±0.002 mm may be desired with some combinations of fine filter and compressor. In an embodiment, fine orifices 214, 216, 218, 220 may be laser etched onto an aperture plate to keep costs low.

FIG. 2 further includes reset valve 222. Reset valve 222 is depicted as a 2 position, 2 port (2/2) solenoid valve that is spring biased in the closed direction. When reset valve 222 is opened, reset valve 222 may exhaust fluid through an exhaust port, allowing air control block 224 to depressurize compressed air 104. Depressurizing compressed air 104 allows air control block 224 to initiate a frothing cycle at a known (ambient) pressure. Advantageously, depressurizing every cycle allows air control block 224 to produce repeatable results from cup to cup.

FIG. 3 depicts a control block 324 apparatus according to an embodiment of the application. Control block 324 includes a body 302, valves 306, 308, 310, and 312, an inlet 314, an outlet 316, a reset valve 322, an orifice plate 326, screws 328, and electrical leads 330. Control block 324 is an example implementation of control block 224. Valves 306, 308, 310, and 312 are an example implementation of valves 206, 208, 210, and 212. Reset valve 322 is an example implementation of reset valve 222.

Body 302 is rectangular box that includes inlet 314, outlet 316. Body 302 provides inlet 314 through which compressed air may enter control block 324. In embodiments, an accumulator (not depicted) may be included or coupled to body 302 separately. For example, compressed air from an air compressor such as compressor 202 or from accumulator 204 may enter control block 324 through inlet 314. Body 302 also includes outlet 316 through which compressed air may exit control block 324. For example, compressed air 104 may exit outlet 316 to flow into fine filter 106. Body 302 provides a fluid management platform upon which valves 306, 308, 310, and 312 may be mounted and operated. Valves 306, 308, 310, and 312 regulate flow through respective fine orifices, which determine the fluid flow between inlet 314 and outlet 316.

Orifice plate 326 is mounted upon body 302. Orifice plate 326 is substantially flat, mounted flush upon the surface of body 302. Valves 306, 308, 310, and 312, and reset valve 322 are mounted upon orifice plate 326. Reset valve 322 of control block 324 is mounted on body 302. Screws 328 couple valves 306, 308, 310, 312, and 322 to body 302. Each of valves 306, 308, 310, 312, and 322 includes respective electrical leads 330. Electrical leads 330 allow for the electronic control of control block 324.

FIG. 4 depicts an exploded view of control block 324 according to an

embodiment of the application. In FIG. 4, it is possible to see details of orifice plate 326, including screw bores 440, fine orifices 438, and unrestricted orifices 436. It is also possible to see gaskets 430, gasket groves 432, and exhaust port 434.

Each of valves 306, 308, 310, and 312 include two screws 328 that may be used to attach each respective valve to body 302. In the exploded diagram of FIG. 4, the screws are not attached to body 302 so that orifice plate 326, gaskets 430, and gasket groves 432 may be seen. Screws 328 pass through each respective valve 306, 308, 310, and 312, through respective screw bores 440 of orifice plate 326, into respective threaded holes 442 in body 302.

Orifice plate 326 is attached to control block 324 between valves 306, 308, 310, and 312 and body 302. For each respective valve 306, 308, 310, and 312, orifice plate 326 includes one unrestricted orifice 436 on the inlet port of the valve and one fine orifice 438 on the outlet port of the valve. In an embodiment, fine orifices 438 are laser etched into orifice plate 326.

Gaskets 430 provide a seal between orifice plate 326 and body 302. Gasket groves 432 provide a seat for gaskets 430.

Reset valve 322 may be attached directly to body 302 with screws 328. In FIG. 4 exhaust port 434 may be seen, which provides an exit for gas vented through reset valve 322.

FIG. 5 depicts a pressure chart 500 of a milk frothing cycle according to an embodiment of the application. Pressure chart 500 is divided into compressor ramp phase 502 and milk frothing phase 504. The Y-axis of chart 500 represents pressure, and the X-axis represents time. The solid line in chart 500 represents a first example milk frothing protocol, and the dotted line represents a second example protocol.

As may be seen in chart 500 milk frothing begins with compressor ramp phase 502. During compressor ramp phase 502, an air compressor builds up an initial amount of differential fluid pressure. In the example of chart 500, compressor ramp phase 502 takes 0.5 seconds to complete.

Once an initial differential pressure is achieved, control block 224 or 324 may open any combination of valves 206, 208, 210, and 212 or 306, 308, 310, and 312 to allow compressed air to pass into fine filter 106, producing milk froth 112. As may be seen from the example solid line milk frothing profile in chart 500, control block 224 or 334 may provide a substantially constant amount of pressure of compressed air through the fine filter. As may be further seen from the example dotted line milk frothing profile in chart 500, control block 224 or 334 may also vary the pressure of the compressed air provided to fine filter 106.

At the end of milk frothing phase 504, the excess fluid pressure is released.

Pressure may be released through fine filter 106 or through reset valve 222 or 322 so that the differential pressure in control block 224 or 334 is essentially zero.

Advantageously, the various embodiments of the application may be

implemented to provide a precise flow of compressed air from an air compressor to a component such as a fine filter. Another advantage is the ability to dampen pulsations from an air compressor. The embodiments of the control block described in the application may be paired with a micro compressor to provide a precise control of fluid while dampening pulsations. One particularly useful application of the control block described is for the application of frothing milk. The embodiments described in this application provide a reliable, repeatable, and inexpensive method of producing high- quality milk froth for beverages.

The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the application. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the application. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the application.

Thus, although specific embodiments of the application and examples are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the application, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other devices and method, and not just to the embodiments described above and shown in the accompanying figures.

Accordingly, the scope of the application should be determined from the claims.

Claims

We claim:

1. A gas regulating device (200) comprising:

an air compressor (202);

a control block (224) configured to receive compressed air, the control block (224) including:

an accumulator (204) in communication with the air compressor (202), a plurality of valves (206, 208, 210, 212) in communication with the accumulator (204), and

a plurality of fine orifices (214,216,218,220), each respective fine orifice (214,216,218,220) being in communication with a respective valve (206, 208,

210, 212); and

a fine filter (106) in communication with the plurality of fine orifices (214, 216, 218, 220), wherein the air compressor (202) is configured to provide compressed air to the fine filter (106) via the plurality of valves (206, 208, 210, 212) and the plurality of fine orifices (214, 216, 218, 220).

2. The gas regulating device (200) of claim 1, wherein the air compressor (202) is a micro compressor.

3. The gas regulating device (200) of claim 1, wherein the air compressor (202) provides a mass flow between 10-70 Nl/h at a pressure of 1.2-1.5 bar to the control block (224).

4. The gas regulating device (200) of claim 1, further comprising:

an orifice plate (326) including the plurality of fine orifices (214, 216, 218, 220), wherein the plurality of fine orifices (214, 216, 218, 220) are laser-etched into the orifice plate (326).

5. The gas regulating device (200) of claim 1, further comprising:

a reset valve (222) in communication with the plurality of fine orifices (214, 216,

218, 220) and the fine filter (106).

6. The gas regulating device (200) of claim 1, wherein the fine filter (106) is embedded in a conduit (102) carrying a fluid (112).

7. The gas regulating device (200) of claim 1, wherein the plurality of valves (206, 208, 210, 212) are operable to provide an electronically configurable fluid flow through the plurality of fine orifices (214, 216, 218, 220) to the fine filter.

8. A control block (224) configured to provide compressed air from an air compressor (202) to a fine filter (106), the control block (224) comprising:

an accumulator (204) in communication with the air compressor (202);

a plurality of valves (206, 208, 210, 212) in communication with the accumulator (204); and

a plurality of fine orifices (214, 216, 218, 220), each respective fine orifice (214, 216, 218, 220) being in communication with a respective valve (206, 208, 210, 212) and the fine filter (106).

9. The control block (224) of claim 8, wherein the air compressor (202) is a micro compressor.

10. The control block (224) of claim 8, wherein the air compressor (202) provides a mass flow between 10-70 Nl/h at a pressure of 1.2-1.5 bar.

11. The control block (224) of claim 8, further comprising:

an orifice plate (326) including the plurality of fine orifices (214, 216 ,218, 220), wherein the plurality of orifices (214, 216, 218, 220) are laser-etched into the orifice plate (326).

12. The control block (224) of claim 8, further comprising:

a reset valve (222) in communication with the plurality of fine orifices (214, 216, 218, 220) and the fine filter ( 106).

13. The control block (224) of claim 8, wherein the fine filter (106) is embedded in a conduit (102) carrying a fluid (112).

14. The control block (224) of claim 8, wherein the plurality of valves (206, 208, 210, 212) are operable to provide an electronically configurable fluid flow through the plurality of fine orifices (214,216,218,220) to the fine filter.

15. A method for making milk foam, the method including the steps of:

filling an accumulator with compressed air from an air compressor;

controlling the flow of compressed air from the accumulator to a fine filter by operating a plurality of valves, each valve of the plurality of valves in communication with a respective fine orifice; and

passing the compressed air into a milk flow via the fine filter.

16. The method of claim 15, further comprising the step of:

venting the compressed air through a reset valve.

17. The method of claim 15, wherein the air compressor is a micro air compressor.

18. The method of claim 15, wherein the step of controlling the flow of compressed air to the fine filter by operating the plurality of valves further includes electronically controlling the plurality of valves.

19. The method of claim 15, wherein the air compressor provides a mass flow of compressed air between 10-70 Nl/h at a pressure of 1.2- 1.5 bar.

20. The method of claim 15, wherein an orifice plate includes the plurality of fine orifices, the plurality of orifices being laser-etched into the orifice plate.