WO2013140281A1

WO2013140281A1 - Apparatus for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps

Info

Publication number: WO2013140281A1
Application number: PCT/IB2013/051534
Authority: WO
Inventors: Michele Madureri; Fabio Gioberti
Original assignee: Gea Mechanical Equipment Italia S.P.A.
Priority date: 2012-03-19
Filing date: 2013-02-26
Publication date: 2013-09-26
Also published as: ITPR20120013A1

Abstract

A procedure for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps, wherein water or another suitable fluid is heated from a traditional supply temperature of about 15-20 °C to a sterilisation temperature of about 130- 150°, provides for the following steps: - maintenance of the sterilisation temperature for a time t from 0.2 s to 30s; - cooling of the sterile fluid by surrender of heat to a double-wall/plate heat exchanger (8), producing a corresponding pre-heating of the non-sterile fluid incoming to said exchanger (8); - flushing of the aseptic chambers of the homogeniser by means of the cooled sterile fluid. An apparatus that realises the procedure comprises, originally, a double- wall/plate heat exchanger.

Description

DESCRIPTION

APPARATUS FOR THERMAL TREATMENT OF WATER WITH REGENERATION FOR FLUSHING ASEPTIC CHAMBERS OF HIGH- PRESSURE HOMOGENISERS OR PUMPS

Technical field

The object of the present invention is an apparatus for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps.

It is substantially an apparatus for metering sterile water (or another suitable fluid) to the aseptic chambers of the homogenisers (environments where there are homogenising plungers and valves).

Background art

From IT 1308543 by the same Applicant, there is known a pump for the treatment of fluids at high pressure comprising a reciprocating plunger in a compression chamber from a fluid intake position to a fluid delivery position. There is a block for each plunger, for the connection of the pumping chamber to the intake and delivery valves housed in lateral containers fixed to the block. Each block comprises two half-parts or plates clamped together and having internal grooves to house an internal manifold connecting the pumping chamber and the intake and delivery valves.

The prior art comprises different types of pumps able to operate at pressures in the range of 500 - 1500 bars.

From EP 1740293 B1 by the same Applicant, there is known a homogeniser for the continuous treatment of fluids at very high pressures comprising at least one reciprocating plunger inside a compression chamber and a guide chamber from a fluid intake position to a delivery position. The compression chamber leads to a manifold, inside a block from which a delivery pipe and an intake pipe branch off. A first seal unit is housed inside the guide chamber, a second seal unit is arranged in proximity to the intersection between the compression chamber and the guide chamber, and a third seal unit is arranged upstream and downstream of each valve and at the intersection between the manifold and the compression chamber.

The presence of aseptic chambers in the homogenisers is dictated by the need to create an aseptic environment at the interface between a sterile/uncontaminated zone (product side) and a potentially non-sterile zone, in which there are mechanical elements that are constantly or occasionally in reciprocating motion between the two zones.

At present, to supply sterile fluid to the homogeniser, a heat exchanger is utilised, and starting from superheated steam, supplied by the user, the heat exchanger condenses it, bringing it to temperature values that are a compromise between the needs of the client and the technical limitations imposed by the static and dynamic gaskets. Condensation takes place inside a braze-welded plate exchanger by means of a coolant consisting of demineralised water (for the purpose of reducing inefficiency due to the presence of calcium deposits). The problem in this system lies in the high operating cost of the system, resulting from the high level of steam consumption.

In an alternative solution known in the prior art, there is instead provided a pump that is capable of maintaining overpressure on the sterile side, with respect to the non-sterile side, so as to prevent contamination of the sterile fluid should cracking of one or more heat exchanger plates occur.

The problem of introducing such a pump lies in the particular operating conditions, that is, a suitable pump should be of sanitary design, be capable of operating at high temperatures (in fact, it should be installed on the sterile side of the system where the temperatures involved are on the order of about one hundred degrees) and, not least in importance, it should operate at very low capacity levels. Such extreme conditions would result in a product with a very high final cost, which would negatively affect the final cost of the system, as well as the complexity of the management electronics. From WO 2011/002376 A1 , an apparatus is known according to the preamble of claim .

FR 2780494 A1 shows an exchanger of the tube-in-tube type which is unsuited to the aims of the present invention. In fact, the exchanger of the tube-in-tube type has a very low exchange efficiency compared to a double-plate (or double-wall) exchanger. Moreover, water or food oil is present in the external pipe, whereas in the internal pipe there is a liquid that is heated: if a hole accidentally forms giving rise to a leak, no possibility for draining is provided and contamination of the external, intermediate fluid occurs.

US 6136362 shows a system for continuous pasteurisation of liquidfood products.

Disclosure of the invention

In this context, the technical task underlying the present invention is to propose an apparatus for metering sterile water that overcomes the drawbacks of the prior art cited above and makes it possible to supply water or sterile fluid to the aseptic chambers of high-pressure homogenisers or pumps in a simple and economical manner.

A further aim is that of enabling drainage in the event of accidental hole formation in the heat exchanger, thereby preventing the problem of contamination.

Said aims are fully achieved by the apparatus that is the object of the present invention, which is characterised as specified in the claims included herein below and in particular, in that it comprises:

- a first heat exchanger for heating the water (or another suitable fluid) to a temperature of 130-150 °C,

- a second exchanger, of the double-wall type with a non-sterile side inlet and a sterile side inlet, in which the second exchanger receives the fluid in the non-sterile side inlet at a traditional supply temperature (normally about 15-20 °C), pre-heating it to a temperature ranging between the traditional supply temperature and the outlet temperature of 130-150 °C from the first exchanger, said pre-heating taking place as a consequence of the fact that the fluid heated by the first exchanger enters the second exchanger sterile side, cooling and surrendering heat in its passage inside the second exchanger.

An object of the present invention is also a corresponding, original procedure that provides three possible steps: Production, SIP and CIP.

Brief description of the drawings

This and further characteristics will become more evident in the following description of a preferred embodiment, illustrated solely by way of non- limiting example in the accompanying drawings, in which:

- Figure 1 shows an overall schema of the apparatus in the production step;

- Figure 2 is an overall schema of the apparatus in the sanification step (SIP = sanification in place);

- Figure 3 is an overall schema of the apparatus in the cleaning step (CIP = cleaning in place);

- Figure 4 is a schema of the second heat exchanger.

Detailed description of preferred embodiments of the invention

With reference to Figure 1 , 1 is used to indicate an inlet for non-sterile water (or another suitable fluid), at a traditional supply temperature preferably of about 15° (and in any case, normally within the range of 15 °C to 20 °C) at a pressure of about 4 bars.

The water passes through a filter 2 and a shut-off valve 3 of a pneumatic type suitable for enabling remote control. Then there is a control valve 4 to maintain a constant pressure (in this particular case at 3.5 bars) and a non-return valve 5 to prevent possible reflux and contamination of the point of use at the inlet.

A pressure gauge 6 may be present for monitoring of the pressure.

The number 7 is used to indicate a 3-way valve, which, when the apparatus is in the production step, directs the water flow originally to the "non-sterile" inlet of a double-wall or double-plate exchanger 8. This is an exchanger in which, between the non-sterile fluid and the heated sterile fluid, there are two plates separated by an air gap 80. In the case of the present invention, there are seven modules in parallel in this double-wall configuration, capable of ensuring the system is intrinsically safe from "cross-contamination".

The functional schema of the second exchanger 8 is illustrated in Figure 4, where the solid line indicates the path of the treated water or fluid, whereas the dashed line indicates the path of the untreated water or fluid. Vertical arrows indicate drainage.

The water leaving the double-wall exchanger 8 feeds a tube bundle exchanger 9 to heat the water preferably to 135 °C and in any case, within the range of 130-150 °C.

The number "10" is used to indicate an inlet for steam at a temperature of about 150 °C and a pressure of about 4 bars that supplies the tube bundle exchanger 9 (shell side) passing through a filter 11 , a hand-operated shut- off valve 12, a pneumatic shut-off valve 13 for remote control and a flow- rate regulating valve 14 for the steam coming from the inlet 10.

Between the valves 12 and 13, there is a separator 15 (collection tank for eventual condensate, to which a condensate trap 16 is connected) and a pressure gauge 17.

The present invention, which is suitable for thermal treatment of water (or of another suitable fluid) with capacities ranging from 50 kg/h to even 300 kg/h, provides for superheating non-sterile water to about 135 °C (or in any case, within the range of 130-150 °C), maintaining the water at this temperature for a time t that is sufficient to reach a value of Fo≥3, where F₀ = t / 60 * 10 ^(T-¹²¹'^rc)/z ,

where T is the fluid sterilisation temperature (which we can assume as being 135 °C) and z is a value that expresses the increase in temperature required to achieve the same lethal effect in 1/10 of the time. Assuming a value of z = 0 °C and F₀=3, the holding time t sufficient to thermally treat the fluid is: with T=130°C, t=23.2s;

with T=150°C, t=0.3s.

In any case, t may be considered as ranging between 0.2 and 30 seconds. The superheated water leaving the tube bundle exchanger 9 feeds a holding tube 18 by means of which the water originally re-enters the double-wall exchanger 8 (sterile side), where it cools down to 40-60 °C, while heating at the same time the cold water coming into said exchanger 8 (non-sterile side) to about 80 °C.

This original recovery of heat makes it possible for the tube bundle exchanger 9 to receive water that has already been pre-heated to 60-80 °C (rather than cold water at a temperature of 15 °C) and therefore less steam is required, with respect to the prior art, to heat the water to 135 °C, with an evident advantage and energy savings.

The sterile water is cooled to temperature values (40-60 °C) compatible with the static and dynamic gaskets present inside the aseptic chambers to be flushed.

In fact, the sterile water leaving the exchanger 8 at a temperature of 40-60 °C passes through a shut-off valve 30 and a needle valve 30a and supplies the aseptic chambers of a high-pressure homogeniser or pump that are schematically indicated by the number 19.

With suitable adjustment of the control valve 4 and the needle valve 30a, precise mechanical control of the fluid flow rate is ensured.

The number 26 indicates a pressure gauge.

Basically, with respect to the prior art, the present invention proves to be more economical in that it eliminates the utilisation of a costly pump (to keep the sterile zone under overpressure conditions for the purpose of preventing contamination), while maintaining safety conditions of the system by utilising a double-wall exchanger, which, in any case, prevents possible risk related to "cross-contamination".

The number 20 indicates a temperature transducer (4-20 mA) by means of which it is possible to display the holding tube outlet temperature and set an alarm value (in the event of a temperature below a pre-established threshold), which brings about an increase in the flow rate of the steam in the inlet 10.

In fact, the transducer (or temperature probe) 20 is connected to a PID 36 (Proportional Integrative Derivative), that is, an electronic automatic regulating device, in practice, a mini PLC, equipped with a selector/switch (between the Production step and the SIP step, and described herein below), which acts upon the pneumatic regulating valve 14, modulating steam entry.

The number 21 indicates an electro-pneumatic converter that receives an electrical signal from the PID 36, transforming it into a pneumatic signal that activates the regulating valve 14.

The exchanger 9 is provided with a drainage line device 27 that has a hand-operated valve, and with an outlet branch, in which there is a condensate recovery device for further reduction of maintenance costs, provided with a shut-off valve 28, a filter 29, a condensate trap 33, a nonreturn valve 34, which enables reintegration of the condensate in the condensate recovery branch of the plant in which the apparatus is housed. The number 35 indicates a shut-off valve for access to the condensate discharge line.

The present invention also permits the execution of cycles of CIP (cleaning in place) and SIP (sterilisation in place) of the exchangers, and the parameters of these processes can be set according to the requirements of the clients.

In particular, in the case of SIP (illustrated in figure 2), that is, the self- sterilisation of the apparatus that is generally activated prior to each new Production cycle, the three-way valve 7 feeds water to the exchanger 9, passing through a non-return valve 22, with half the flow rate with respect to the flow rate utilised in the previously described Production step, so as to enable the exchanger 9 to bring the water from 15 °C to 135 °C more easily. The water at 135 °C then passes through the holding tube 18 and the double-wall exchanger 8, and exits through a shut-off valve 31 , a needle valve 31a and a condensate trap 31b.

Normal conditions of SIP treatment provide for maintaining a temperature above 121.1 °C for a minimum of 30 minutes.

This temperature is measured at the outlet of the system.

The number 24 indicates a safety valve to prevent overpressure, whereas

25 indicates a temperature probe.

The temperature probes/transducers 20 and 25, the PID 36, the electro- pneumatic converter 21 and the regulating valve 14 constitute a safety device that controls the process temperatures and governs operation of the apparatus according to parameters that can be defined and varied by the user (Production and SIP cycles).

In the case of CIP (illustrated in figure 3), a cleaning solution enters through a shut-off valve 23 and enters the exchanger 8 (non-sterile side); it then passes into the exchanger 9, in the holding tube 18 and lastly through the exchanger 8 (sterile side), to be discharged through a pneumatic shut-off valve 32 that can be remote controlled.

The CIP parameters are defined by the user based on the characteristics of the water utilised in the production step and of the cleaning product. As concerns the valves 30, 31 and 32, it is evident that their open/closed status in the various steps is as follows:

Production Step: 30 open, 31 and 32 closed;

SIP Step: 30 closed, 31 open, 32 closed;

CIP Step: 30 and 31 closed, 32 open.

The Applicant retains that it is not necessary to explain the status of the other valves in detail, as for a person skilled in the field, their positions and operation prove to be comprehensible from a reading of the present description and the attached schemata illustrating operation in the Production, SIP and CIP steps.

The numbers 37 and 37a indicate hand-operated drain valves, constituting a drainage device, which are useful in the event that one wishes to empty the system, whereas 38 indicates a thermometer for displaying the preheating temperature of the water.

The thermal treatment of water (or another suitable fluid) for the purpose of flushing the aseptic chambers of homogenisers and pumps according to the present invention, thus has the advantages of compactness (reduced dimensions), remote operability by means of electrical and pneumatic controls with control logic managed by instrumentation on the electrical panel, lower cost of the system, lower operating costs, (owing to the heat recovery system and lower consumption of water and steam), intrinsically safe operation and the possibility of setting the operating parameters of the system according to the needs of the clients/users.

The apparatus offers the option of self-sterilisation (SIP cycle), maintaining a temperature above 121.1 °C for a minimum of 30 minutes.

Unlike tube-in-tube exchangers of the type such as that illustrated in FR 2780494 A , the second double-plate exchanger 8 provides for improved efficiency, heat recovery and maintenance of aseptic conditions even in the event of the accidental formation of a hole in the exchanger, without the use of any additional pumps and owing to the air gaps in which any eventual contamination remains confined.

Claims

1. An apparatus for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps, of the type comprising a first heat exchanger (9) for heating the water (or another suitable fluid) to a temperature of 130-150°C,

characterised in that it comprises a second heat exchanger (8), of the double-wall type with a non-sterile side inlet and a sterile side inlet, wherein the second exchanger receives the fluid in the non-sterile side inlet at a traditional supply temperature, pre-heating it to a temperature ranging between the traditional supply temperature and the outlet temperature of 130-150 °C from the first exchanger, said pre-heating taking place as a consequence of the fact that the fluid heated by the first exchanger (9) enters the second exchanger (8) sterile side, cooling and surrendering heat in its passage inside the second exchanger (8).

2. An apparatus for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps, of the type comprising a first heat exchanger (9) for heating the water (or another suitable fluid) to a temperature of 130-150°C,

characterised in that it comprises a second heat exchanger (8), of the double-plate type with an air gap, and has a non-sterile side inlet and a sterile side inlet, said second exchanger (8) being a pre-heating device (non-sterile side) for pre-heating the fluid to be treated and a cooling device (sterile side) for cooling the treated fluid from the first exchanger (9).

3. The apparatus according to claim 2, wherein the second exchanger (8) is of the double-plate type with vertical walls and with more than one module in parallel.

4. The apparatus according to claims 1 , 2 or 3, wherein there is a safety device that controls the process temperatures and governs operation of the apparatus according to parameters that can be defined and varied by the user, comprising temperature probes/transducers (25, 20), a PID (36) (Proportional Integrative Derivative = an electronic automatic regulating device, a mini PLC) that sends an electrical signal to an electro- pneumatic converter (21), which activates a flow rate regulating valve (14) for the steam entering the apparatus.

5. The apparatus according to claims 1 , 2 or 3, wherein there is a condensate recovery device, located in an outlet branch from the first exchanger (9) and comprising a shut-off valve (28), a filter (29), a condensate trap (33), a non-return valve (34) and a shut-off valve (35).

6. The apparatus according to claims , 2 or 3, wherein there is a drainage device (27) for the first exchanger (9) with a hand-operated valve.

7. The apparatus according to claims 1 , 2 or 3, wherein there is a device for draining the apparatus, comprising hand-operated drain valves (37, 37a) for emptying the apparatus.

8. A procedure for thermal treatment of water with regeneration for flushing aseptic chambers of high-pressure homogenisers or pumps, wherein water or another suitable fluid is heated from a traditional supply temperature of about 15-20°C to a sterilisation temperature of about 130- 150°,

characterised in that it provides the following steps:

- maintenance of the sterilisation temperature for a time t comprised between 0.2 and 30 s;

- cooling of the sterile fluid by surrender of heat to a double-wall/plate heat exchanger (8), producing a corresponding pre-heating of the non-sterile fluid incoming to said exchanger (8);

- flushing of the aseptic chambers of the homogeniser by means of the cooled sterile fluid.

9. The procedure according to claim 8, wherein the cooling temperature is 40-60°C, whereas the pre-heating temperature is 60-80°C.

10. The procedure according to claim 8, wherein there is provided a SIP (Sanification In Place) or self-sterilisation step that can be activated on demand, wherein all the conduits and base elements of the system (double-wall exchanger (8) tube bundle exchanger (9), holding tube (18)) are flushed for at least 30 minutes with a delivery of fluid equal to 50% of that utilised in the normal Production process, the fluid being heated to a temperature above 121.1 °C.

11. The procedure according to claim 8, wherein there is provided a CIP (Cleaning In Place) or cleaning step that can be activated on demand, wherein all the conduits and base elements of the system (double-wall exchanger (8), tube bundle exchanger (9), holding tube (18)) are flushed with a cleaning fluid.