HK1125158B - Priming valve device for water circuit of beverage machine - Google Patents

Description

Priming valve device for a water circuit of a beverage machine

Technical Field

The present invention relates to a priming valve device capable of ensuring priming (priming) of a pump in a water path. The invention also relates to a beverage machine, such as a coffee machine, comprising such a priming valve device.

Background

In modern coffee machines, a beverage can be prepared by passing hot water under pressure through a container or chamber containing beverage ingredients. Water is pumped from a water tank by a pressure pump, e.g. a piston pump, which pushes the water into a heater for heating, usually a thermoblock (thermobloc), a boiler or an instant heater, and sprays hot water through the beverage ingredients. The beverage ingredients are extracted or dissolved under pressure and the beverage extract or mixture is released from the container. Pressure pumps can deliver pressures in excess of 5 bar, typically 15 to 20 bar; this pressure depends on the counter pressure against which the container is subjected, the ingredients (e.g. granulometry, size of the bed, etc.), the counter pressure valve, etc., but also on the specific opening mode of the container and/or the specific filtration mode of the beverage. Some containers require a pump to deliver high pressure and the opening for releasing the beverage extract is achieved by tearing the plastic or aluminum film of the container.

Priming of the pressure pump typically occurs when the tank becomes empty, air enters the pump, and the tank must be refilled by the user. The pressure difference in the pump is too high between the inlet and outlet of the pump, where the pressure is about atmospheric pressure, and the pressure at the outlet of the pump is much higher, and water can no longer be pumped. To solve this problem, a portion of the water downstream of the pump must be drained, which may require opening the beverage chamber and causing wastage of the container.

Another problem relates to limestone scaling of heaters. The heater must preferably be kept under pressure to ensure that the hot water remains in the liquid state. The pressure drop results in the conversion of liquid water to steam, which leads to serious limestone scaling problems. In particular, heaters such as thermoblocks are very sensitive to fouling problems due to the narrow cross-section of the tubes within the coil heating circuit, which will clog quickly.

Attempts have been made in the prior art to develop priming valve devices for vibrating pumps, in particular in EP 1003997B 1. The device realizes the functions of self-starting water injection of the pump, balancing negative pressure in the boiler when the boiler is cooled down, and protecting the boiler from overpressure. The apparatus comprises a non-return valve or check valve, a bleed valve disposed upstream of the non-return valve to perform a pump self-priming function, and a safety valve allowing air to enter the boiler and associated check valve downstream and in parallel with the bleed valve. Such devices are complex and may cause leakage problems due to the need for multiple individual valves to operate in a coordinated manner; each valve acts on a separate elastic means having a different compressive strength. In particular, the device is prone to leakage when used to prime a piston pump. The device is unstable due to water flow fluctuations that occur at the frequency of the pump (i.e., it performs very small repeated on/off corresponding to the vibration of the pump). Another problem with this prior art is that the check valve creates a back pressure of several bar, since the check valve can only open under the dynamic pressure generated by the pump. As a result, the extraction of the beverage ingredient is performed at a pressure lower than the optimal pressure range without a back pressure valve.

Disclosure of Invention

There is therefore a need to propose a solution for priming a pressure pump in a water circuit of a beverage machine which operates more simply and more efficiently, i.e. which should reduce leakage problems and severe pressure losses of the prior art devices.

The present invention meets these needs.

To this end, the priming valve device of the present invention comprises a housing assembly comprising a water inlet connectable to a side of the pump, a water outlet connectable to a side of the heater, and a drain and vent for discharging water and/or air to the outside during priming. The device comprises a valve assembly associated with the housing assembly, the valve assembly comprising a valve member configured to be selectively moved to a closed position of the drain and vent portion when the water inlet reaches a certain water pressure under the action of the pressure pump during extraction or brewing. In one aspect of the invention, the pump member is movable to the closed position of the outlet by elastic return when the pressure in the inlet falls below the elastic return pressure of the valve member.

For example, when the water pump is switched off after extraction or brewing, the pressure in the water inlet is sufficiently reduced. The valve member is forced back to the closed position of the outlet port due to the pressure exerted by the resilient means exceeding the water pressure in the inlet port when the pump is stopped.

It should be noted that the resilient means may be an integral part of the structure of the valve member itself, or a separate component such as a spring.

It is therefore an aspect of the present invention to use the same valve member to selectively block the drain/vent path or the normal water flow path within the waterway. Unlike prior art devices, the device of the present invention is simpler and more reliable and avoids leakage problems. Furthermore, instead of using multiple valve members, the same valve member is moved in one block from two positions, thus eliminating the problem of the valve member moving in an uncoordinated manner due to various factors, such as scale build-up or component fatigue.

In one aspect of the invention, the valve member is movable in a generally transverse direction relative to the longitudinal axis of the outlet to a closed position of the outlet. In this arrangement, the static pressure of the fluid is sufficient to hold the valve open, unlike the prior art longitudinal arrangement which only requires dynamic pressure to open the valve. In addition, the elastic restoring force or pressure for closing the water outlet may be relatively low, while still effectively and properly closing the water outlet. As a result, pressure loss in the apparatus is minimized. Therefore, the pressure available for brewing or extraction of the beverage is higher.

In one aspect of the invention, the valve member may be made insensitive to flow fluctuations caused by the sinusoidal frequency pattern of the pump. To this end, the valve member may have at least one flexible portion. In particular, the valve member may comprise a diaphragm portion.

According to another aspect of the invention, in order to close the water outlet in a watertight manner (watertight manner), the valve member comprises a first end portion having a first sealing surface configured to cooperate in a watertight manner with a sealing bearing surface at the water inlet. The valve member preferably further comprises a sealing portion which separates the water outlet from the drainage and venting portion in a water-tight manner. Thus, the valve member performs two functions simultaneously: first, the water inlet is selectively sealed when no pressure is applied or the pressure is low, and second, the water outlet is isolated from the drain/vent flow path.

In another aspect of the invention, to drain or vent the water inlet, the valve assembly further comprises at least one vent/drain restriction (restriction) or small gap between the water inlet and the drain and vent portion.

The ventilation/drainage restriction or gap may be provided before the valve member or within the valve member itself.

In a preferred mode, the restriction or gap is provided at an inlet of a communication passage provided across the valve member for discharging air through the valve member. The restriction may also be the entire passage itself. The restriction or gap can have various shapes, sizes and numbers. However, the restriction or gap should be small enough so that the pressure loss created by the drain/vent restriction or gap only through the low pressure air or water/air present in the water inlet is too small to move the valve member to close the vent and drain. Conversely, when the water in the inlet is under pressure during pumping, the pressure loss created by this restriction or gap becomes high enough to move the valve member to the closed position of the vent and drain portion and thereby open the outlet. In other words, the viscosity difference between water and air enables to close the valve or keep the valve open.

As a result, if the pump is working with an empty water tank, the pump is primed by equalizing the pressure downstream of the pump and by eventually removing the air that has been pumped. Thus, air is moved to the ventilation and drain portion through the valve assembly.

The size of the restriction or gap is related to the force of the resilient means (e.g. a spring) of the valve assembly. For example, the surface of the vent/drain restriction or gap may be at 0.1mm²And 2mm²More preferably 0.25mm²And 1mm²In the meantime.

Furthermore, according to another aspect, in order to block the water/air communication passage in the closed position of the drain and vent portion, the valve member further comprises a second end portion having a second sealing surface configured to cooperate in a watertight manner with the sealing support surface of the drain and vent portion. The second end is generally located on an opposite side of the valve member. Thus, depending on the relative end positioning of the valve member within the housing assembly, one or the other sealing surface forms a watertight seal in the desired position.

In some cases, i.e. for flushing or descaling purposes, the valve member may be positioned in an intermediate position in which the sealing surface is not in watertight engagement with the housing assembly, thereby enabling solids and dust to be removed from the equipment surface and more effectively flushed through both the water outlet and the drain/vent. For this purpose, the pressure in the water inlet may be reduced to a value at which the valve member is partially restored by the resilient means but does not reach the fully closed position. The partial return pressure of the elastic means is determined to be equal to the pressure exerted by the pump during flushing. Thus, the pump pressure during flushing results from a lower back pressure generated in the water circuit when there is no beverage ingredient to be extracted or brewed to sufficiently increase the pressure.

The second sealing surface of the valve member may preferably have an annular shape, such as at least one frustoconical or rounded surface, which preferably fits with an annular concave, flat or inclined surface of the drain/vent portion.

The valve member may be guided along at least one guide of the housing assembly on each side of the valve member to move from one position to another. Each guide means may take a different form, for example in the form of a pin or other equivalent means.

In addition, the valve assembly includes a guide bushing at each end of the valve member, the guide bushings fitting within the pockets of the valve member; each bushing is complementarily guided by one of the guiding means, for example a guiding pin. The guide bushing may be made of a material that is more durable and harder than the material of the valve member. The harder material improves the accuracy of the gap for water/air drainage maintained between the bushing and the pin on the water inlet side. The material may also wear less than the material of the valve member, thereby enabling repeated reciprocating movements.

For example, the bushing may be made of metal or durable (wear resistant) plastic.

Unlike this, the valve member may be made of an elastomeric material. The elastomeric material is chosen because it can be repeatedly compressed against the sealing surface, can withstand frequent changes in water pressure conditions without cracking or breaking, and can extend the life of the device. Alternatively, the valve member may be made of a silicone material.

Drawings

Other advantages, features and objects of the present invention will become apparent from the following detailed description of preferred embodiments of the invention, when read in conjunction with the accompanying drawings, in which:

FIG. 1 shows an overall plan view of the valve apparatus of the present invention;

FIG. 2 is a cross-sectional view of the view of FIG. 1 taken along a longitudinal mid-vertical plane;

FIG. 3 shows an exploded view of the elements making up the valve apparatus of the present invention;

FIG. 4 is a cross-sectional view similar to FIG. 2, but in the open position of the water outlet during extraction or brewing;

FIG. 5 shows a cross-sectional view of the valve member;

FIG. 6 shows a left side view of the valve member;

FIG. 7 shows a cross-sectional view of a first housing component or "main housing" along a longitudinal intermediate vertical plane;

FIG. 8 is a left side view of the housing components;

FIG. 9 is a right side view of the housing components;

FIG. 10 shows a cross-sectional view of a second housing component or "primer flush connector";

FIG. 11 is a perspective view of a second housing component;

fig. 12 is a right side or interior view of the second housing component.

Detailed Description

In fig. 1-3, a priming valve device 1 according to a preferred embodiment is shown. The priming valve comprises a housing assembly 2, which housing assembly 2 comprises two component parts connected together to internally house a valve assembly 3. Priming valve device 1 has a simple structure, since only a limited number of components are required to achieve the desired pump priming, water circuit pressure control and cleaning/flushing functions.

The housing assembly 2 comprises a first component or main housing 4, shown in detail in fig. 7-9, and a second component or low-pressure connector 5, shown in detail in fig. 10-12, forming the drain and vent portion of the device.

The main housing 4 has a water inlet 6 comprising a short pipe section with connection means adapted to connect the water inlet to the conduit of the water circuit on the downstream side of an optional pressure pump. The alternative pressure pump is typically a piston pump which can deliver high pressures in the range of about 5 to 20 bar. The main housing 4 also has a water outlet 7, which water outlet 7 forms a short pipe section connectable to a conduit of a downstream waterway, so that water leaves the apparatus when pressurized by the pump. Typically, the water outlet is connected to a tube connected to the heater of the water circuit. The heater may be a thermobloc, a boiler or an instant heater, such as a cartridge heater or a thick film tube heater.

The water inlet 6 and the water outlet 7 are both in communication with a valve chamber 8 of the housing assembly. The water inlet and outlet are preferably oriented at an angle a to each other, the angle a being less than 180 degrees, preferably between 10 and 175 degrees, most preferably between 90 and 120 degrees (fig. 7). The angular positioning of the water outlet with respect to the water inlet is part of the innovative concept of the device, wherein the same valve assembly is able to perform selective opening/closing of the water circuit and draining/venting, as will be explained below.

As shown in fig. 3, the valve assembly 3 is housed in the valve chamber 8. The valve assembly is composed of a valve member 9, two guide bushes 10, 11 and an elastic return means 12. The valve member 9 is shown in detail in figures 5 and 6. The valve member comprises a first end portion 13 and a second end portion 14 opposite the first end portion. The first end portion has a substantially circular cross-section and has a tubular shape which is larger than the cross-section of the water inlet incorporated in the valve chamber and which contains an annular first sealing surface 15. The surface 15 is inclined outwardly to engage a flared surface 16 of the valve chamber located at the periphery of the outlet of the water inlet 6 in sealing engagement during closure of the inlet. As can be seen from fig. 2, the sealing engagement of the surfaces 15, 16 enables the water inlet 6 to be isolated from the water outlet 7 when the valve member is pressed towards the water inlet.

The second portion 14 is provided with a second sealing surface 17, which surface 17 forms, for example, a conical surface similar to a frustoconical annular surface, configured to engage with a sealing support surface 18 of the low-pressure connector 5 having a substantially complementary shape. The low voltage connector 5 is shown in detail in fig. 10-12. The connector terminates inwardly in a slightly rounded tubular surface 18, which surface 18 cooperates with the second sealing surface 17 of the valve member.

The valve member is guided for reciprocating movement within the valve chamber 8 by two pins, an inlet pin 19 and an exhaust pin 20 located on opposite sides of the valve chamber 8 respectively. The pin is longitudinally aligned along the main longitudinal axis I of the valve chamber and extends into the valve chamber 8. The valve member is formed with two opposed cavities 21, 22 which are dimensioned to receive the guide bushes 10, 11 respectively. The bushing is preferably formed of a wear resistant material such as a corrosion resistant metal, e.g., stainless steel or aluminum, or a hard plastic (e.g., PTFE) having a low coefficient of friction. The bushing facilitates sliding or reciprocating movement of the valve member along the pin due to reduced friction and wear, so that the device may be used frequently.

For draining or venting water from the water inlet towards the drainage and venting portion, a water communication channel 23 traverses the valve member. The passage is a conduit having an inlet 24 located in the first cavity 21 of the valve member and an outlet 25 on the side of the valve member.

The valve member further comprises a diaphragm portion 26 forming a flange-type seal portion terminating in a seal engaging end portion 27, which end portion 27 is secured by assembly of the two component parts 4, 5 of the apparatus within an annular seal sub-chamber 28. This flange seal has the function of ensuring that a watertight arrangement is formed between the water outlet 7 and the drain/vent 5 of the device. Thus, the outlet 25 of the communication passage of the valve member opens into a clearance annular recess 30 of the valve chamber, which recess 30 communicates with the drain/vent portion but is isolated from the outlet 7 of the apparatus. As a result, when the valve member is in the closed position of the water outlet, the water pressure can be maintained on the outlet side due to the first sealing surface 15 of the first end portion and the diaphragm portion 26 of the valve member; while water can be drained and ventilated to/from the drain/vent portion 5 through the communication passage.

Returning to the inlet side, it can be seen from fig. 7 that the inlet has a wall 31, the wall 31 being oriented transversely to the direction of the water and containing small holes 32 allowing water to enter the valve member. When the valve member is in the closed position towards the water inlet, water can enter the valve member through a small gap or clearance between the bushing 10 and the inlet pin 19. Of course, the gap may be formed by a hole and/or channel or the like provided in the bushing, pin and/or valve member itself.

On the side of the drain and vent portion 5, the valve member is urged by resilient means 12, which resilient means 12 may be a coil-shaped spring placed around the drain pin 20. The elastic means exert a constant compression action on the guide bush 11, directly or indirectly, against the valve member, so as to force the valve member to close the water inlet 6 when the pressure inside the water inlet 6 drops below a threshold value, corresponding for example to the pressure when the pump is stopped. The force of the resilient means is calculated so that an effective sealing force is exerted by the valve member against the water inlet when the pressure upstream of the apparatus is sufficiently reduced. It is important to note, however, that even a small restoring force is sufficient to move the valve member, so that pressure losses within the apparatus can be greatly reduced. As a result, a smaller pressure loss within the device enables brewing or extraction of the beverage ingredient with more pressure from the pump. This also provides the opportunity to use smaller and thus cheaper pressure pumps.

As shown in fig. 2, 7 and 10, the main housing 4 and the connector 5 are connected together by a snap-fit arrangement. To this end, the main housing 4 has a substantially cylindrical base 34, the base 34 having a series of ports 35, i.e. at least two, preferably four, ports, circumferentially distributed on the wall of the base. The connector 5 is generally cylindrical and has a series of flexing tabs 36 which can deflect towards the centre line of the connector when the connector is introduced into the cylindrical base of the main housing. Each tab extends at its periphery with an abutment 37, which abutment 37 is configured to engage within the corresponding port 35 so that the connector is secured in place within the base. It should be noted that the connector also extends externally along its centre line with a tubular portion 38 of smaller diameter, which tubular portion 38 can be used to connect a flexible tube portion (not shown). As a result, water drained from the apparatus may be returned to the water tank or discarded into a waste water container. The drain portion 38 has an aperture 39 disposed in a transverse wall 40 that supports the pin 20. In an alternative embodiment, instead of a snap-fit arrangement, the main housing 4 and the connector 5 may be screwed together.

The priming valve device works in the following manner.

With reference to fig. 1, the priming valve device is intended to be connected to a water circuit of a beverage apparatus, such as an espresso-type or multi-beverage-type coffee machine, which usually comprises a pressure pump that does not prime itself well. A piston pump reciprocating at a frequency of about 50/60Hz is typically used to satisfy the priming problem. Typically, such pumps do not initiate water injection when the pump is full of air and this air cannot leave the water circuit. The water inlet 6 is connected to the downstream side of the pump, and the water outlet 7 is connected to the upstream side of the heater.

When the pump is not running, the priming device is at rest as shown in figure 1. The spring 12 forces the valve member against the inlet sealing surface 16. Thus, the water pressure at the inlet side of the device is low and the pressure can be equalized between the water inlet and the drain/vent by the valve member, in particular via the communication channel 23. The low pressure in the inlet maintains a small pressure differential across the pump, which promotes self-priming. At the same time, the valve member seals the water outlet, ensuring that the heater can be maintained under sufficient water pressure to prevent water being converted to steam while the heater is still hot.

When preparing a beverage, the beverage machine is usually loaded with a portion of beverage ingredient, for example a capsule containing roast and ground coffee, and the pump is turned on. The valve member is thus pushed backwards by the pressure exerted by the water, compressing the spring. Since the pressurised surface of the valve member is much larger than the cross-sectional surface of the vent/drain gap of the valve assembly, the valve member is forced to open rapidly and the water outlet 7 is opened as shown in figure 4. This mode is the normal extraction or brewing mode of the beverage machine.

If the supply of water to the pump is stopped, for example because the water tank is empty, air will fill the pump. The beverage maker may be stopped and water may be replenished to the water tank. The priming device will thus be again in the position of fig. 1. Since the valve member is closed at the water inlet side, the water pressure at the water inlet side will decrease. When the pump is restarted, air will easily pass the valve member due to its low viscosity and will be discharged through the discharge tube portion 38. Sufficient pressure will build up in the water outlet to subsequently force the valve member to open the water outlet in the normal extraction/brewing mode.

In one possible configuration, the valve member 9 may be positioned in an intermediate flushing position, in which the sealing surfaces 15, 17 are disengaged from the sealing bearing surfaces 16, 18, respectively, of the housing assembly 2. Thus, the valve assembly may partially open under the pressure of the water established in the water inlet. This pressure is lower than the normal extraction pressure when the beverage unit is loaded with beverage ingredients; this reduced "flush pressure" is sufficient to open the valve assembly but insufficient to compress the resilient means, i.e. spring 12, to a position where a seal is achieved at the drain/vent. As a result, dust or scale particles can be discharged through the drain/vent portion, i.e. via the channel 23 and the water outlet 7.

The device of the invention may also be integrated as a removable or non-removable part of the water pump, or as a part of a water heater. The invention therefore also relates to a water pump or water heater comprising the apparatus of the invention.

Claims (22)

1. Priming valve device (1) for a beverage machine, comprising:

a housing assembly (2), the housing assembly (2) comprising a water inlet (6) connectable to a side of the pump, a water outlet (7) connectable to a side of the heater, and a water discharge and ventilation portion (5) for discharging water and/or air to the outside during priming,

a valve assembly (3) associated with the housing assembly (2), the valve assembly comprising a valve member (9), the valve member (9) being configured to be selectively moved to a closed position of the drain and vent portion (5) when the water inlet (6) reaches a certain water pressure under the action of the pressure pump during extraction or brewing,

characterised in that the valve member (9) is movable by elastic return to a closed position of the outlet (7) when the pressure in the inlet (6) drops below the elastic return pressure of the valve member.

2. Priming valve device according to claim 1, characterized in that the valve member (9) is movable in a substantially transverse direction with respect to the longitudinal axis of the water outlet (7) into a closed position of the water outlet (7).

3. Priming valve device according to claim 1, characterized in that the valve member comprises a diaphragm part (26).

4. Priming valve device according to claim 3, characterized in that the diaphragm part (26) separates the water outlet (7) from the drain and vent part (5) in a water-tight manner.

5. Priming valve device according to any one of claims 1 to 4, characterized in that, in order to close the water outlet (7) in a watertight manner, the valve member (9) comprises a first end (13) having a first sealing surface (15), which first sealing surface (15) is configured to cooperate in a watertight manner with a sealing bearing surface (16) at the water inlet.

6. Priming valve device according to claim 5, characterized in that the valve assembly (3) further comprises at least one small restriction or gap between the water inlet (6) and the water discharge and venting portion (5).

7. Priming valve device according to claim 6, characterized in that the valve member (9) further comprises a second end portion (14) having a second sealing surface (17), which second sealing surface (17) is configured to cooperate in a watertight manner with a sealing bearing surface (18) of the drain and vent section (5).

8. Priming valve device according to claim 7, characterized in that the valve member (9) is accommodated in the valve chamber (8) and guided for reciprocating movement in the valve chamber (8) by two guide pins (19, 20); the two guide pins (19, 20) are located on opposite sides of the valve chamber (8) and are longitudinally aligned along a main longitudinal axis (I) of the valve chamber (8) and project into the valve chamber (8).

9. Priming valve device according to claim 8, characterized in that the valve assembly (3) further comprises a guide bush (10, 11) at each end (13, 14) of the valve member, which guide bush (10, 11) fits into a cavity (21, 22) of the valve member; each guide bushing (10, 11) is complementarily guided by a guide pin (19, 20).

10. Priming valve device according to claim 9, characterized in that the gap is provided between the guide bushing (10) and the guide pin (19).

11. Priming valve device according to claim 3, characterized in that the housing assembly (2) comprises two component parts which are connected together so as to engage the diaphragm part (26) in a watertight manner.

12. Priming valve device according to claim 11, characterized in that the diaphragm part (26) extends beyond the sealing engagement end (27).

13. Priming valve device according to claim 11 or 12, characterized in that the two component parts of the housing assembly (2) are connected by snap-fit means.

14. Priming valve device according to claim 11 or 12, characterized in that the two component parts of the housing assembly (2) are connected by means of a screw thread.

15. Priming valve device according to any one of claims 1 to 4, characterized in that the valve member (9) is made of an elastomeric material.

16. Priming valve device according to claim 15, characterized in that the valve member is made of silicone material.

17. Priming valve device according to any one of claims 1 to 4, characterized in that the valve assembly (3) comprises elastic means (12), which elastic means (12) are associated with the valve member (9) so as to urge it back into the closed position of the water outlet (7) when the pressure inside the water inlet (6) decreases.

18. Priming valve device according to claim 17, characterized in that the resilient means (12) is a separate spring or a resilient integral part of the valve member (9) itself.

19. Priming valve device according to any one of claims 7 to 10, characterized in that the valve member is positionable in an intermediate flushing position in which the sealing surfaces (15, 17) of the valve member are disengaged from the sealing bearing surfaces (16, 18), respectively, of the housing assembly (2).

20. Beverage machine comprising a priming valve device (1) according to any one of claims 1 to 19.

21. Alternative pressure pump comprising a priming valve device (1) according to any one of claims 1 to 19.

22. Water heater comprising a priming valve device (1) according to any one of claims 1 to 19.