METHOD AND DEVICE FOR INFUSION MOLDING
The resin infusion molding process addresses the risk of resin overflow damaging vacuum pumps by implementing a detection and drainage system for buffer tanks, ensuring continuous suction and resin reuse.
Patent Information
- Application Number
- FR2023004746
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2023-04-13
- Filing Date
- 2023-05-12
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2043-05-12
AI Technical Summary
Current resin infusion molding processes face risks of resin damage to vacuum pumps due to unmonitored buffer tanks, which can lead to resin overflow.
The process includes a detection system for buffer tank filling levels, allowing for automatic drainage before the vacuum pump is damaged, and enables continuous suction by switching between buffer tanks. Additionally, the system recovers and reuses vacuum resin for molding.
This solution prevents resin damage to vacuum pumps, ensures continuous suction during molding, and recovers reusable resin, enhancing process efficiency and safety.
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Abstract
Description
Title of the invention: METHOD AND INFUSION MOLDING DEVICE Technical field of the invention
[0001] The present invention relates to a method and a device for infusion molding. It applies, in particular, to the creation of molded resin objects, for example swimming pool or ship hulls. State of the art
[0002] Currently, resin infusion processes by molding are carried out by vacuuming a mold, the vacuum sucking the resin into a tank and filling the mold. However, there are risks of the resin reaching the vacuum pump and damaging it.
[0003] Some devices include a buffer storage tank between the mold and the vacuum pump to prevent any possible overflow from reaching the vacuum pump. However, if the buffer tank is not monitored by an operator, the risk of damage is always present. Summary of the invention
[0004] The present invention aims to remedy all or part of these drawbacks.
[0005] The present invention makes it possible to detect that the buffer tank is approaching a filling and emptying it before the vacuum pump is damaged. In addition, by switching between different buffer tanks, the present invention makes it possible to maintain suction continuously. Finally, the present invention makes it possible to recover the sucked resin and reuse it for molding. Brief description of the figures
[0006] Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the device and method which are the subject of the present invention, with reference to the appended drawings, in which: [Fig.l] represents, schematically and in the form of a flowchart, a particular succession of steps of the method which is the subject of the present invention and [Fig.2] schematically represents a first particular embodiment of the device which is the subject of the present invention. Description of the embodiments
[0007] The present description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.
[0008] The expression "and / or", as used herein and in the claims, is to be understood as meaning "either or both" of the elements so conjoined, i.e., elements which are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" are to be interpreted in the same way, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present, other than the elements specifically identified by the "and / or" clause, whether or not they are related to these specifically identified elements.Thus, by way of non-limiting example, a reference to "A and / or B", when used in conjunction with open language such as "comprising" may refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
[0009] As used herein in the description and in the claims, "or" is to be understood as having the same meaning as "and / or" as defined above. For example, when separating elements in a list, "or" or "and / or" is to be interpreted as inclusive, i.e., the inclusion of at least one, but also more than one, number or list of elements, and, optionally, additional elements not listed. Only terms clearly indicating the contrary, such as "only one of" or "exactly one of", or, when used in the claims, "consisting of", refer to the inclusion of only one element of a number or list of elements.
[0010] As used in this specification and in the claims, the expression "at least one", with reference to a list of one or more elements, is to be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements and not excluding any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than the specifically identified elements in the list of elements to which the expression "at least one" refers, whether or not related to those specifically identified elements.Thus, by way of non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B", or, equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, without A present (and optionally including elements other than A); in yet another embodiment. of embodiment, at least one, possibly including more than one, A, and at least one, possibly including more than one, B (and possibly including other elements); etc.
[0011] In the claims, as well as in the description below, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "composed of", and the like, are to be understood as being open, i.e., as meaning including, but not limited to. Only the transitional expressions "consisting of" and "consisting essentially of" are to be understood as closed or semi-closed transitional expressions, respectively.
[0012] It should be noted from now on that the figures are not to scale.
[0013] [Fig. 1] shows a schematic view of an embodiment of the method 10 which is the subject of the present invention. The method 10 is described in correspondence with the embodiment of the device 20 shown in [Fig. 2] and which is not to scale.
[0014] The resin infusion molding method 10 comprises: - a step 101 of placing at least one part of a mold 22 under vacuum, - a step 102 of suction of the resin from a reservoir 21 and circulation of the resin in said part of the mold 22, under the effect of the vacuum, - a step 103 of recovering the resin in a storage means, 24a, 24b and / or 24c, - a step 104 of detecting a filling level in the storage means 24a, 24b and / or 24c, - a comparison step 105 of the filling level with a predetermined limit value and - a step 107 of emptying the storage means, 24a, 24b and / or 24c when the filling level is higher than the predetermined limit value.
[0015] Before starting the infusion process 10, a reservoir 21 is filled with resin. The reservoir is connected to a mold 22 by means of at least one resin distribution pipe. Preferably, the mold 22 is traversed, alternately, by a resin distribution pipe and an air suction pipe. The air suction pipes are connected to at least one storage means, 24a, 24b or 24c. A vacuum pump 28 is connected to the storage means 24a, 24b or 24c and sucks air from the mold through the suction pipes and the storage means, 24a, 24b and / or 24c. The pipes are arranged so that the resin passes through the mold during the suction step 102. The pipes are sealed to the mold 22, to the storage means 24a, 24b or 24c and to the reservoir 21. The mold pipes are, for example, spiral sheaths provided with resin dispersion orifices.
[0016] During the vacuum step 101, the vacuum pump 28 is activated. Once the vacuum is sufficient in the pipes and the mold 22, the suction step 102 and circulation of the resin is automatic. This step can also be carried out manually.
[0017] At least one storage means called a “buffer tank”, 24a, 24b or 24c is placed between the mold 22 and the vacuum pump 28. Preferably, each resin suction pipe is connected to two buffer tanks, 24a, 24b or 24c.
[0018] In the embodiment shown in [Fig.2], three buffer tanks, 24a, 24b and 24c are mounted in parallel between the mold 22 and the vacuum pump 28. During the suction step 102, the resin is sucked into at least one buffer tank, 24a, 24b and / or 24c, after passing through the mold and before reaching the vacuum pump.
[0019] Preferably, each buffer tank, 24a, 24b and 24c, is sealed.
[0020] To carry out the detection step 104, each buffer tank, 24a, 24b and 24c, comprises a detector of a filling level, 25a, 25b and 25c respectively, in the buffer tank, 24a, 24b and 24c. Each detector of the filling level, 25a, 25b or 25c, can be a float mounted on a lever which actuates a push button when the filling level reaches a predetermined limit value. The push button can then be considered as a means of comparing the filling level with a predetermined limit value which then carries out the comparison step 105.
[0021] In embodiments, the filling level detector is a resin level sensor and / or a buffer tank mass sensor, 24a, 24b or 24c which sends a digital signal representative of the level and / or mass sensed. When the filling level detection step 104 is carried out by measuring the mass of the buffer tank, the predetermined limit value being a value representative of a mass.
[0022] The digital signal is interpreted by a control means 27 implementing a computer program for comparison with a predetermined limit value. In embodiments, the control means is a microprocessor 27 which comprises a human-machine interface by which the predetermined limit value can be configured. Preferably, the microprocessor 27 is part of a computer which comprises at least a keyboard, a screen and a computer memory. Information concerning the implementation cycles of the method 10 can be analyzed and stored in the computer memory.
[0023] When the filling level is higher than the predetermined limit value, the microprocessor 27 sends a drain command to a valve, 26a, 26b or 26c respectively located in the base part of each buffer tank, 24a, 24b or 24c. The resin stored in the buffer tank, 24a, 24b or 24c, then flows out by gravity or by expulsion under pressure. The emptying step 107 of the storage means, 24a, 24b and / or 24c is then carried out.
[0024] In the embodiment shown in [Fig.2], a pipe 29 is connected to each valve, 26a, 26b and 26c, to transport the drained resin to the tank 21. The pipe 29 then carries out the return step 108.
[0025] The pipe 29 may be provided with a pump and / or any means known to those skilled in the art for improving the purity of the resin. The step 109 of pumping the drained resin to the reservoir is therefore carried out by the pump. In embodiments, the pumping step may be carried out by pressurizing the resin contained in the buffer reservoir, 24a, 24b or 24c, to be drained. The resin is then evacuated from the buffer reservoir, 24a, 24b or 24c, under the effect of the overpressure. The pressurization may be carried out by another pump 30 connected to the buffer reservoirs, 24a, 24b or 24c.
[0026] The purification step 110 can be carried out by a sieve aimed at removing impurities or lumps from the resin.
[0027] In optional embodiments, a switch 23 is placed between the mold 22 and each buffer tank 24a, 24b and 24c. The switch 23 can be controlled by a control means 27 to switch from one buffer tank, 24a, 24b or 24c, to another. Preferably, only one buffer tank, 24a, 24b or 24c, is drained at a time, the buffer tanks, 24a, 24b or 24c, being connected in parallel.
[0028] Preferably, the switch 23 is a set of valves, manually or electrically controlled, located on each pipe connecting a buffer tank, 24a, 24b or 24c, to the vacuum pump 28 and on each pipe connecting a buffer tank, 24a, 24b or 24c, to the mold 22.
[0029] The switch 23 is preferably activated by the control means 27 when one of the buffer tanks, 24a, 24b or 24c is filled. The switch 23 then directs the flow of sucked resin to another buffer tank, 24a, 24b or 24c. Thus, one of the tanks is emptied while another is filled, which makes it possible to improve the efficiency of the method 10 and the device 20. For example, the switch 23 may comprise an electronically controlled valve directing the flow of resin alternately to a buffer tank, 24a, 24b or 24c, among the three buffer tanks, 24a, 24b or 24c.
[0030] In embodiments in which the detection step 104 is performed by measuring the mass of each reservoir, the switching step 106 is performed proportionally to the mass detected in the first storage means.
[0031] For example, a second predetermined limit mass, lower than the predetermined limit mass corresponding to the command for emptying the buffer tank, 24a, 24b or 24c, is programmed in the control means 27. From the second predetermined limit mass, the buffer tank, 24a, 24b or 24c, previously being filled is filled by a decreasing flow rate until its mass reaches the predetermined limit mass corresponding to the emptying command. Another buffer tank, 24a, 24b or 24c, can be filled with an increasing flow rate simultaneously. The control of the filling flow rate can be carried out by the control means 27 and each electronically controlled valve of the switching means 23.
[0032] In other words, a first buffer tank, 24a, 24b or 24c, begins to be filled. When its mass reaches the second predetermined limit mass, the filling rate is gradually reduced. Simultaneously, a second buffer tank, 24a, 24b or 24c, begins to be filled with a flow rate value such that the total filling rate is unchanged, regardless of the number of buffer tanks, 24a, 24b or 24c being filled.
[0033] Preferably, the filling flow rate of the first buffer tank, 24a, 24b or 24c, is inversely proportional to the mass of said buffer tank, 24a, 24b or 24c, once the second limit mass has been exceeded.
[0034] Preferably, in the embodiments in which each pipe coming from the mold 22 is connected to at least two buffer tanks, 24a, 24b or 24c, to carry out the emptying step 107 of one of said buffer tanks, 24a, 24b or 24c, the valves 23 connected to the tank which is going to be emptied are closed, then the valve, 26a, 26b or 26c respectively is opened and an overpressure is carried out thanks to the pump 30 to eject the resin from the tank.
[0035] It should be noted that, depending on the mold and the part to be molded, even if all the reservoirs are filled simultaneously, the filling flow rate may vary from one reservoir to another.
[0036] Preferably, if each pipe from the mold 22 is connected to two buffer tanks, 24a, 24b or 24c, simultaneously, only one of the two buffer tanks, 24a, 24b or 24c, is emptied at a time.
[0037] In embodiments, to form an infusion molded part, several emptying steps 107 of different tanks can take place. The first emptying step, of the production of a part, is triggered when the filling level exceeds a first predetermined limit value. Then, once the emptying of the buffer tank in which the filling level has exceeded the first predetermined limit value, the next buffer tank to be emptied is the most filled among the other buffer tanks.
[0038] In other words, the method 10 comprises a step of comparing the filling level of each buffer tank, 24a, 24b or 24c, each other emptying step 107 being applied to the tank whose filling level is the highest.
[0039] In embodiments, the method 10 comprises a step of controlling a step of emptying 107 of at least one storage means, 24a, 24b or 24c according to at least one priority rule.
[0040] The priority rule may be that defined above: the highest level buffer tank, 24a, 24b or 24c, is emptied first. Optionally, the priority rule depends on a filling rate of each buffer tank, 24a, 24b or 24c. Optionally, the priority rule depends on a predetermined critical limit value, greater than the predetermined limit value. Optionally, the priority rule depends on a physical property of the resin used such as its viscosity or its polymerization time.
[0041] Preferably, the method 10 further comprises an emergency stop step 110 when the filling level is greater than the predetermined limit value for each storage means. Thus, when for each buffer tank, the detected filling level is equal to the predetermined limit value, which represents a blockage of the emptying on each of the buffer tanks, the vacuum pump 28 is stopped to avoid damaging the vacuum pump 28.
[0042] In embodiments (not shown), each buffer tank, 24a, 24b or 24c is connected to a means for cleaning at least a portion of the buffer tank, 24a, 24b or 24c. For example, an injection nozzle may be connected to the cleaning means. Preferably, a cleaning step is implemented after each emptying for the emptied buffer tank, 24a, 24b or 24c. The cleaning means is, for example, an acetone tank connected to the buffer tank, 24a, 24b or 24c, by a pipe and an acetone pump to the buffer tank, 24a, 24b or 24c.
[0043] Preferably, the means of the device 20 are configured to implement the steps of the method 10 and their embodiments as set out above and the method 10 as well as its different embodiments can be implemented by the means of the device 20.
[0044] Benefits provided
[0045] According to a first aspect, the present invention relates to a resin infusion molding method, which comprises: - a step of placing at least one part of a mold under vacuum, - a step of sucking the resin from a reservoir and circulating the resin in said part of the mold, under the effect of the vacuum, - a step of recovering the resin in a storage means, - a step of detecting a filling level in the storage means, - a step of comparing the filling level with a predetermined limit value and - a step of emptying the storage means when the filling level is higher than the predetermined limit value.
[0046] Thanks to these provisions, the resin does not enter the vacuum pump, which prevents its damage.
[0047] In embodiments, the draining step includes a step of returning the drained resin to the tank.
[0048] Thanks to these arrangements, the resin contained in the storage means is recovered and reused for other iterations of the molding process.
[0049] In embodiments, the return step comprises a step of pumping the drained resin back to the reservoir.
[0050] Thanks to these arrangements, the drained resin can be conveyed more quickly to the tank.
[0051] In embodiments, the method which is the subject of the present invention further comprises, before the emptying step, a step of switching, when the filling level is greater than the predetermined limit value, a first storage means with a second storage means, mounted in parallel, to carry out the recovery and emptying steps.
[0052] Thanks to these arrangements, it is possible to switch between two storage means without interrupting the suction.
[0053] In embodiments, the method which is the subject of the present invention further comprises, once a first emptying step has been carried out, at least a second step of emptying the storage means whose filling level is the highest.
[0054] Thanks to these provisions, a tank is always emptied, which makes it possible to increase the efficiency of the device.
[0055] In embodiments, the method which is the subject of the present invention comprises a step of controlling a step of emptying at least one storage means according to at least one priority rule.
[0056] Thanks to these provisions, once the first emptying has been carried out, the filling of the other tanks is limited to avoid a situation in which several tanks must be emptied simultaneously.
[0057] In embodiments, the emptying step is implemented for only one storage means at a time.
[0058] Thanks to these arrangements, suction is carried out continuously in the mold.
[0059] In embodiments, the method which is the subject of the present invention further comprises an emergency stop step when the filling level is higher than the predetermined limit value for each storage means.
[0060] Thanks to these provisions, in the event that emptying is prevented, for example by a blocked drain pipe, the process can be stopped automatically to avoid damaging the vacuum pump.
[0061] In embodiments, the step of detecting the filling level comprises a step of measuring the mass of the storage means, the predetermined limit value being a value representative of a mass.
[0062] Thanks to these arrangements, a mass measuring means can be arranged under each storage means, to detect the approach of a switching, for example.
[0063] In embodiments, the switching step is performed proportionally to the mass detected in the first storage means.
[0064] Thanks to these provisions, from a certain mass value, a second storage means can begin to fill while the first is filled with a decreasing flow rate.
[0065] In embodiments, the method which is the subject of the present invention comprises a step of purifying the drained resin.
[0066] Thanks to these provisions, impurities can be removed from the resin in order to obtain a homogeneous molding and limit manufacturing defects.
[0067] According to a second aspect, the present invention relates to a resin infusion molding device, which comprises: - a means for placing at least part of a mold under vacuum, - a resin tank, - a means of sucking the resin from the reservoir and circulating the resin in said part of the mold, under the effect of the vacuum, - a means of storing and recovering the resin, - a means for detecting a filling level in the storage means, - a means for comparing the filling level with a predetermined limit value and - a means of emptying the storage medium when the filling level is higher than the predetermined limit value.
[0068] The aims, advantages and particular characteristics of the device which is the subject of the present invention being similar to those of the method which is the subject of the present invention, they are not recalled here.
Claims
Claims
1. Method (10) for resin infusion molding, characterized in that it comprises: - a step of placing at least one part of a mold under vacuum (101), - a step of sucking (102) the resin from a reservoir and circulating the resin in said part of the mold, under the effect of the vacuum, - a step of recovering (103) the resin in a storage means, - a step of detecting (104) a filling level in the storage means, - a step of comparing (105) the filling level with a predetermined limit value - a step of emptying (107) the storage means when the filling level is greater than the predetermined limit value and the method further comprising, before the emptying step (107), a step of switching (106), when the filling level is greater than the predetermined limit value, a first storage means with a second storage means, connected in parallel,to carry out the recovery and emptying steps (107).,
2. The method (10) of claim 1, wherein the draining step includes a step of returning (108) the drained resin to the tank.
3. The method (10) of claim 2, wherein the returning step includes a step of pumping (109) the drained resin back to the reservoir.
4. Method (10) according to one of claims 1 to 3, which further comprises, once a first emptying step (107) has been carried out, at least a second emptying step (107) of the storage means whose filling level is the highest.
5. Method (10) according to one of claims 1 to 4, which comprises a step of controlling a step of emptying (107) at least one storage means according to at least one priority rule.
6. Method (10) according to one of claims 1 to 5, in which the emptying step is carried out for only one storage means at a time.
7. Method (10) according to one of claims 1 to 6, in which the step of detecting the filling level is carried out by measuring the mass of the storage means, the predetermined limit value being a value representative of a mass.
8. Method (10) according to one of claims 1 to 7, wherein the switching step (106) is carried out proportionally to the mass detected in the first storage means.
9. Device (20) for molding by resin infusion, characterized in that it comprises: - a means for placing at least a part of a mold (22) under vacuum (28), - a resin reservoir (21), - a means for sucking (23) the resin from the reservoir and circulating the resin in said part of the mold, under the effect of the vacuum, - at least two storage means (24a, 24b, 24c) for recovering the resin, - a means for detecting (25a, 25b, 25c) a filling level in the storage means, - a means for comparing (27) the filling level with a predetermined limit value - a means for emptying (26a, 26, 26c) each storage means when the filling level is greater than the predetermined limit value and the device further comprising a means for switching, when the filling level is greater than the predetermined limit value, a first storage means with a second storage means, mounted in parallel.