MXPA98010126A - Molding cooling system for vid article forming machines - Google Patents

Abstract

The present invention relates to a system for cooling moldings for forming machines of articles of glass of multiple sections, comprising: a cooling apparatus for each section, driven by a motor controlled by a control system, to regulate the speed of the engine and, consequently, the flow and pressure of the cooling air that will control the temperature of the mold that is the variable of the

Description

MOLDING COOLING SYSTEM FOR GLASS ARTICLES FORMING MACHINES. BACKGROUND OF THE INVENTION A. FIELD OF THE INVENTION. The present invention relates to a mold cooling system for I.S. machines. glassware formers and, more specifically, to a mold cooling system by independent fans directly harvested to the frame of each section of the machine. B. DESCRIPTION OF THE RELATED ART. In the process of the formation of glass containers in machines I.S., a continuous cooling in the molding is required, in order to maintain a constant temperature within a pre-established operating range for the forming of the containers. When this temperature varies, this variation causes defects in the manufacture of the containers. The traditional way to achieve the cooling of the moldings is by means of an array of high power fans (250 Hp up to 600 Hp.), Which provide the necessary flow of cooling air, normally located in special rooms located in the basement. plant. Typically, various fan arrangements are provided with the lowest possible number of fans that can supply cooling air to a greater number of machines, each typically with six to eight forming sections.

Considering an oven that supplies the glass to four I.S. machines, the ideal is to have one fan per machine, plus a backup in case of failure of any of the fans that are operating. In order to save electrical energy and equipment, an arrangement of four fans connected to a "plenum" camera arranged outside the fan room, and having four discharges, is commonly provided. In this arrangement only three fans work, leaving the fourth fan as a backup. At each discharge of the "plenum", a duct called "shoe" is attached to each respective machine; from each "shoe" a duct is derived, which supplies the cooling air to the molding of each section of said machine. The diameter of said "shoe" gradually decreases to form a cone towards the last section of the machine. The shape of the cone of the "shoe" is in order to distribute the same volume of air in all sections of the machine. At the exit of the plenum and before each "shoe", a shutter damper is included, activated by an electric actuator connected to a controller to regulate the flow of cooling air to the machines. This controller has two transmitters as inputs; one of static pressure and one of air temperature inside the "shoe". The purpose of this controller is to ensure a constant pressure in the system, so that indirectly a constant temperature is maintained in the molding. The temperature transmitter is used to compensate for this pressure since at night, with cooler air, more efficient cooling is achieved and, therefore, requires less air.

To exemplify a daily operation, the operator disables a section of any of the machines for reasons of changing molds, crowns, etc. or for mechanical or electronic maintenance, by disabling said section, the operator closes a butterfly gate at the base of the frame so as not to allow the air to cool the moldings too much. Closing this gate causes an immediate increase in pressure in the rest of the sections of the machine causing disturbances due to temperature variations in the molding. The controller compensates for this excess pressure by closing the shutter door in the "shoe" but said action is slow. At the time when the operator reopens the gate, the opposite happens, the pressure of the system is reduced, having less air to cool the moldings, causing temperature variations. Another problem with this system is that when a fan fails, all the machines stop due to cooling deficiency. Even when connected in "plenum", when a fan stops, there is a risk for all the machines since with only two fans it is not possible to maintain the necessary flow for cooling. This stoppage of machines is until the backup fan is put to work. In the current cooling system there is also a low efficiency since there are losses in the path when transporting the air from the fan to the machine. As an example, an 8 section type machine "F" requires a flow of 3500 ft3 / min per section. A 32"pressure water column.The dimensions of a fan for this machine, in theory, would be 28000 ft3 / min. (3500 x 8 = 28000 ft3 / min.) at the same pressure of 32" column of water. In reality for this machine a fan of 32,000 ft3 / min is selected. With a 34"column of water, this is done to compensate for the losses.These losses are converted into significant weights.Another very important point is the cost of a backup fan.These fans have high costs.For example, a fan and motor 32,000 ft3 / min to 34"column of water has a cost of approximately $ 30,000.00 USD. The cost of your starter is approximately $ 7,500.00 USD. We can see that to support the process they have $ 37,500 USD unemployed without doing anything. In summary, among the disadvantages of conventional mold cooling systems that use a bank of fans and a manifold to distribute the cooling air to the sections of the forming machine, the following can be mentioned: 1. High consumption of electrical energy; 2. When the fan fails, the whole machine or several machines are affected when you have a plenum; 3. Large losses and pressure drops due to the trajectory of the air ducts. 4. Need to have special large rooms for fans; . A backup that is very expensive; When stopping a section the pressure increases the "shoe" and the surplus air is passed to the other sections causing disturbances of the process; . Each start of these fans causes large spikes of electric current (which in the case of Mexico, the Federal Electricity Commission could sanction for exceeding maximum demand) as well as mechanical stress on the rotor and bearings. It is, therefore, highly desirable to have some arrangement to make the cooling system more efficient so that it has minimal losses. Likewise, it is necessary to have an arrangement so as not to impact production when sections of an I.S. machine are stopped. It also aims to save electricity because after the compressors, the cooling of the molding is the second concept of greater electricity consumption in the plants. So, if an arrangement can be obtained that provides all of the above, production costs will decrease as less energy is consumed and productivity increases due to fewer defects in the products, caused by poor cooling of the moldings. Contrary to what could be thought and proposed, the cooling system of moldings of the present invention, which incorporates and operates a single fan for each section of each machine, is surprisingly much more efficient, effective and economical than conventional cooling systems , due, among other reasons, to the advantages that are discussed below.

All the disadvantages of conventional systems are overcome by the cooling system of moldings of the present invention, by eliminating the large fans, the fan room, the plenum and the "shoe" and replacing all this equipment with a fan individual by section. This fan is dimensioned to what is specifically required by the section, that is, without oversizing due to losses. Al, having a fan per section, it is allowed to have the flow required by the molding and thus maintain its stable temperature. When the operator stops a section, there will be no pressurization and thus the other sections are not harmed. In the absence of pressurization or depressurization of which has been previously discussed, there will be no temperature variation in the mold and therefore the process will not be affected. Moreover, the operator will be able to stop the fan and automatically save electricity and all this without affecting the process.

In case of failure of a fan, only one section is affected without harming the other sections. Being modular (one fan per section) will have facilities for quick changes, so as not to impact productivity. A high efficiency is obtained since having the fan directly coupled in the frame of the machine I.S. there are negligible pressure losses. The operator will be able to vary the amount of air, not by closing the existing gate in the frame, but by varying the speed of the fan motor. In this way, energy is saved since the fan moves less load. In the traditional system it closes in the discharge and the reduction of the air is obtained but with a minimum of energy saving. A very important advantage of the mold cooling system, of the present invention, is the fact that to support this process it is enough to have a spare unit. This small unit is much cheaper than the large unit already mentioned, that is to say that there is less investment without producing. In this invention, an inverter (alternating current motor speed control) can be incorporated for each fan, with which the air flow can be varied in a more efficient manner since, by varying the speed of the motor, we vary the flow and In addition, electricity is saved. Because the power supply varies with the cube of the fan speed, the consumption is considerably reduced. At 60% of the volume of the fan, the energy consumption is only 22% which is obtained from (0.60) 3. The inverter control uses 40% less energy than when using the control in the suction, and uses 66% less energy than flow control in the discharge. In other words, at 60% of the volume of the fan, the energy consumptions are the following according to the control method used: METHOD OF CONSUMPTION Control in Discharge: 88% Control in Suction: 62% Control by Investor: 22% This shows that there is a considerable saving of energy since by statistics most of the time the fans are working in a range of 40% to 70% of their volume capacity. Additionally, a temperature control of the mold can be included. In the current way of operating, the operating temperature is inferred according to the flow and pressure of the air. In contrast to the above, optical, infrared or thermocouple sensors can be included for measuring the temperature of the mold, so that using a controller a closed loop is made using the inverter to vary the speed of the motor and consequently the flow and air pressure and finally the temperature that is actually the process variable. Last, but not least, in the manufacture of glass containers a limiting factor for increases in production speed is the temperature of the mold. Therefore, in accordance with the present invention, an air pre-cooling system can be incorporated so that, as a result, the production speed can be increased. This is achieved due to the fact that cold air has a greater capacity for extracting heat than ambient air. When pre-cooling the air, it will require less air to cool, therefore the speed of the inverter is lowered and consequently a greater energy saving is obtained. The pre-cooling system can be considered as a water cooler or a kind of honeycomb with cold water in the suction or discharge. With this pre-cooling system care should be taken that the cooling air does not contain water because the presence of water can cause a number of defects in the product. Among other advantages of the mold cooling system, of the present invention, there can be mentioned: zero impact in process due to temperature variations in the mold when stopping sections that do not affect the other sections in the machine; energy saving; reduction in the cost of equipment due to not having an expensive backup; Reduced risk when a fan fails since only one section will be impacted. In summary among the advantages presented by the mold cooling system of the present invention, in relation to the conventional systems mentioned in the foregoing, the following can be mentioned: 1. Energy saving using inverters; 2. Reduction in defective by variation of temperature in the mold to have a better controlled air; 3. reduction in molding preheating time, because the fan is kept off for the desired time; 4. Negligible pressure and flow losses due to short paths; 5. When a fan fails, it affects only one section; 6. When stopping and tearing sections do not affect the others, that is, there are no disturbances to the process, because the "shoe" that does not exist is pressurized and depressurized; . By stopping sections (dead times) the fans can be stopped automatically with great savings in terms of electrical energy; . No special rooms are required; 9. Because it is a modular system, any change is very easy and quick; 10. It uses less expensive spare parts, with an inverter and a fan; 11. A spare serves several machines. 12. When working with a smaller number of sections, the fans of these sections are stopped (in eight-section machines working in six sections) and there is an important saving in terms of the electric energy required. 13. There are no current peaks when starting fans as the acceleration ramp of the inverter is used; 14. When starting with a soft ramp there is no effort in bearing and bearing (premature wear of the equipment); 15. Ready to close the molding temperature control loop (the inverter has the integrated PID controller). SUMMARY OF THE INVENTION. It is therefore a principal object of the present invention to provide a cooling system for moldings for glass article forming machines by means of independent fans directly coupled to the frame of each section of the machine. It is also a principal object of the present invention to provide a cooling system for moldings for glass article forming machines, of the aforementioned nature, which reduces the defects of the articles produced by variation of temperature in the mold, by providing a better air controlled by this system. It is still a principal objective of the present invention to provide a cooling system for moldings for glass article forming machines, of the aforementioned nature, which allows to include inverters in the motors, so that it is possible to keep any of the fans turned off for maintenance or adjustments in a section, during a desired time, saving energy. It is also a main objective of the present invention to provide a system for cooling moldings for forming machines of glass articles, of the aforementioned nature, by which, by disabling any section does not affect the others, that is, there are no disturbances to the process, because it is not pressurized and depressurizes the "shoe" that no longer exists. These and other objects and advantages of the present invention will become apparent to those of ordinary skill in the art from the following detailed description of the invention, which is presented in connection with a specific embodiment of the invention, illustrated in the drawings. attachments BRIEF DESCRIPTION OF THE DRAWINGS. Figure 1 is a schematic diagram of the conventional mold cooling system for I.S. machines. forming of glass containers; and Figure 2 is a schematic diagram of the cooling system of moldings for glass article forming machines, in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION. In order to serve as a comparative reference, referring to the Figure 1, and for a furnace that supplies glass to four IS machines, the ideal system for cooling moldings ideally comprises four fans or fans V1, V2, V3 and V4, three of which operate to supply cooling air at four o'clock. machines, leaving one as backup in case of failure of any of the fans that are operating. These fans V1 to V4 are located in special rooms located in the basement of the plant (not illustrated), each fan generally has a power between 250 Hp. up to 600 Hp., each of which, for a typical machine of 8 sections type "F" providing by section a flow of 3500 ft3 / min. a 32"column of water, a" plenum "P chamber consisting of a 46" diameter manifold, outside the fan room, which joins the four fans V1 to V4 and which has four discharges D1, D2, D3 and D4; four ducts known as "shoes" Z1, Z2, Z3 and Z4, each of whose "shoes" Z1 to Z4 is respectively coupled to a discharge D1 to D4 of the chamber "Plenum" P, and is directed to each of the machines; each of the "shoes" Z1 to Z4 gradually decreases in diameter to form a cone towards the last section of the machine and comprises an adjustable gate C1, C2, C3, C4, and a cooling duct DE1, DE2, DE3, DE4 .... DEn, each of which is directed to each section of each machine; from each cooling duct DE1 to DE4 of the "shoe" Z1 to Z4, the hoses (not shown) are derived for the cooling of the moldings. The shape of the cone of the "shoes" Z1 to Z4 is in order to distribute the same volume of air in all sections of the machine. The gate of each "shoe" Z1 to Z4 is generally driven by an electrical actuator connected to a controller not illustrated. This controller has two transmitters as inputs; one of static pressure and one of air temperature inside the "shoe". The purpose of said controller is to ensure a constant pressure in the system, so that, indirectly, a constant temperature in the molding is maintained. A temperature transmitter (not shown) is used to compensate for this pressure since at night, with cooler air, more efficient cooling is achieved and requires less air. Unlike the conventional system described above, the cooling system of moldings for glass article forming machines, of the present invention, illustrated in Figure 2, comprises: a cooling apparatus, referred to as CA1 to CA8, for each section of each machine, coupled to the frame F of each respective section S1 to S8 of an IS machine.

Each cooling apparatus CA1 to CA8 comprises a fan F1 to F8, driven by a motor M1 to M8 comprising a control system CS1 to CS8, which includes an inverter 11 to 18 which controls the motor speed M1 to M8, through which the air flow is changed, saving electrical energy.

Said control system CS1 to CS8 further includes a temperature sensor, such as a thermocouple or which can be optical or infrared (not illustrated), to determine the temperature of the mold, so that the control system is performed in closed loop for control the inverter 11 to 18 in order to vary the speed of the motor M1 to M8 of the cooling apparatus CA1 to CA8 and consequently the flow and pressure of the cooling air and finally the temperature which is the process variable. It is advisable to include an air pre-cooling system (not illustrated) that can consist of a water cooler or a honeycomb with cold water, in the suction or discharge of air from each cooling apparatus CA1 to CA8, in order to increase the capacity of extracting heat from the cooling air, thereby reducing the amount of cooling air, which in turn allows the inverter to lower its speed, resulting in a saving in energy consumption. It should therefore be understood that the cooling system of moldings for glass article forming machines, of the present invention, is not limited exclusively to the modalities described and illustrated above, so that experts in the field will remain trained by the teachings of the present invention, to suggest modifications and modalities thereto, which will be clearly contained in the scope of this invention, as claimed in the following claims.

Claims (6)

1. CLAIMS. 1. Molding cooling system for glass article forming machines, with multiple individual forming sections, characterized in that it comprises a cooling apparatus for each section of each machine, coupled to the frame of the section. The system according to claim 1, characterized in that the cooling apparatus is a fan driven by a motor comprising a control system that controls the motor speed, by means of which the air flow is changed, saving electrical energy. 3. The system according to claim 1, characterized in that the control system includes a detector to determine the temperature of the mold, so that the control system is performed in closed loop to control the inverter in order to vary the speed of the engine of the cooling apparatus and consequently the flow and pressure of the cooling air and finally the temperature that is the process variable. 4. The system according to claim 2, characterized in that the detector for determining the temperature of the mold is an optical, infrared, or thermocouple detector, by means of which the temperature of the molding is determined. 5. The system according to claim 1, characterized in that the cooling apparatus comprises a system for pre-cooling the air in order to increase the heat extraction capacity of the cooling air, thereby reducing the amount of cooling air , which in turn allows to lower the speed of the inverter, obtaining as a consequence a greater saving in the energy consumption. The system according to claim 5, characterized in that the pre-cooling system consists of a water cooler or a honeycomb species with cold water in the suction or discharge of air from the cooling apparatus.