RU2261175C2 - Device for detection of a temperature variations, in which a corresponding sensitive element is located - Google Patents

Abstract

FIELD: devices for detection of temperature variations.

SUBSTANCE: the invention is pertaining to the device for detection of a temperature variations, which contains a thermo-sensitive component including a final detector mounted on the external surface preferably of a cylindrical body. The device contains a resilient ring installed in a contact with a body and supplied with a hole, in which the terminal sensor is placed. The resilient ring has a cut-out, that increases a resilient adaptability of the ring. It is preferable that the outer surface of the ring there is a perimetric flute, and the hole is accessible due to the corresponding manufacture according to the form of the internal surfaces of the flute. Inside rings the may be done a through groove, so that the flute may be expanded near to the hole. The nozzle for injection of thermoplastic polymer contains a hollow cylindrical body, the internal cavity of which is made so, that to create a possibility for the thermoplastic polymer injected through the rear inlet opening to flow through it. The nozzle also contains an injection head located on the front tip section of the hollow cylindrical body and supplied with a front discharge channel. The thermoelectric measuring device contains a terminal temperature detector. The nozzle also has a device for installation of the terminal detector on the external surface of the hollow cylindrical body. The technical result of the given device and the nozzle consists in development of the device adapted for mounting of the thermo-sensitive element for measurement of temperatures of the cylindrical body, preferably made from a metal, which would be suitable for an easy multiple installation and dismantling, had a low cost and might be realized with utilization of readily available methods and materials.

EFFECT: the invention ensures the easy multiple installation and dismantling of the device, its low cost and a possibility to realize its utilization with the help of readily available methods and materials.

7 cl, 12 dwg

Description

The invention relates to a certain type of device for installation in a predetermined position with the possibility of removing the sensing element in close proximity to or in direct contact with a critical point or critical zone of a cylindrical body, usually, although not exclusively, made of metal, and especially near the end of said body .

Ideally, the aforementioned device can be used in connection with a device for installing a removable thermoelectric measuring device for measuring the temperature of the injection nozzle for injecting a flow of molten thermoplastic polymer and, as a result, for indirectly measuring the temperature of said molten polymer. In this regard, in the following description, all references will be made to this use case, although it should be understood that the present invention can be used in exactly the same way in all technical cases and applications where it is necessary or felt to measure the external temperature of a cylindrical body in accordance with with the attached claims.

More specifically, the aforementioned nozzle is preferably used in injection molding machines of a thermoplastic polymer when the flow of such a polymer in its molten, i.e. in a liquid state, it either flows into the corresponding channels known in the art as “heated runners” and placed inside the corresponding plate, or it is injected directly from the injection machine injection into a plurality of mold slots formed by a pair of corresponding half-molds.

The term "heated runner" is widely used in the generally accepted technical vocabulary in this particular industry, so that its use in this context will not create any difficulties for specialists.

A commonly used practice is the use of thermocouple devices for continuously measuring the temperature of a heated injection nozzle; In order to be able to control the temperature near the outlet channel of such a nozzle, it is important that the thermocouple itself is placed as close as possible to the front of the nozzle. The possibility of accurate determination and rigid stabilization of the position of the thermocouple is also very critical and decisive. Therefore, the sensor, i.e. the measuring head of the measuring device must be fixed very accurately and securely, especially during installation and maintenance of nozzles in the injection mold.

This requirement must be unconditionally observed in each case of removing the nozzle for any reason, and therefore the need for technical solutions is clear enough to ensure the quick removal and reinstallation of the thermocouple, ensuring in any case its extremely accurate and constant positioning.

From the description of US Pat. No. 5,405,258, a method is known consisting in introducing a sensor or measuring junction of a thermocouple into an injection nozzle used to inject molten thermoplastic polymer; such a sensor, although it can provide the most accurate control of the polymer temperature, requires, however, the use of some additional devices; in addition, it is held in place only by the pressure differential between the nozzle itself and the section of the plate containing the heated runners made in the form of a truncated cone. This is practically the reason for both the increased complexity in installing the thermocouple and the very probable instability when positioning the thermoelectric measuring device itself.

According to the method described in US Pat. No. 5,028,227, the thermocouple is positioned in close proximity to the nozzle by making a correspondingly inclined hole outside the nozzle and the most accurate and accurate installation of the thermocouple into it. However, since with each nozzle replacement, it becomes necessary to first remove the thermocouple and then install it again in a new nozzle, the necessary degree of accuracy required by this process will be the inevitable cause of a significant lengthening of the time required to complete the process itself, as well as complicating it.

A solution is known, described in US patent No. 4875848, which includes the use of the end part of the nozzle having the shape of a truncated cone to make a transverse blind hole 138, into which a thermocouple is then inserted and placed. However, to ensure the necessary stability of the entire assembly, the nozzle itself, the heating element associated with it, and the thermocouple must be attached to each other, preferably by soldering with hard or soft solder, and this, of course, carries, in addition to the complexity of such an additional process, and the inevitable drawback is that when it is necessary to replace the nozzle, there is also the need to solder the thermocouple or even replace it with a new one.

From the description of US patent No. 5795599, a method is known consisting in installing a thermocouple by drilling or, in any case, making a hole in the front of the nozzle going to the back of it, introducing the thermocouple into it and bending the conductors connected to it in the rear direction by half full angle (i.e. 180 °). The thermocouple mounted on the nozzle in this way is fixed, i.e. fixed on it with the help of an external additional ring, which is equipped with many corresponding protrusions in the form of a crown. After such a ring is properly installed to fix the thermocouple in place, the said projections are bent by force to fix the ring, and therefore the thermocouple, on the end of the nozzle. In any case, a solution of this kind can be described as very laborious both during installation and when removing the thermocouple.

From the description of US Patent No. 5,326,251, a method is known that consists in installing two separate thermocouples in two corresponding positions in the end of the nozzle in order to more efficiently control the flow, i.e. curve, temperature gradient in the polymer while injecting it into the mold. It really turns out to be especially useful when working with plastics of various types and properties. However, in the remaining cases, the proposed solution seems unreasonably complicated.

From the description of US patent No. 5312242, a method is known consisting in the use of a hollow tube acting as a protective sheath that surrounds and encloses the thermocouple conductors at their specific lengths. The real purpose of such a protective shell is to prevent possible polymer leakage to other parts of the mold along the thermocouple itself. This solution, however, does not offer any advantages with regard to the installation and removal methods of the thermocouple itself.

US patent No. 5436388 discloses a solution in which a thermocouple is placed similarly to that described in the aforementioned US patent No. 5795599, but fixed in place according to the example shown in the aforementioned US patent No. 5405258. Naturally, the disadvantages inherent in the mentioned patents are repeated here.

Based on the foregoing, the main objective of the present invention can be seen in creating a device adapted to mount a temperature-sensitive element for measuring the temperature of a cylindrical body, preferably made of metal, which could overcome and eliminate the disadvantages of the above solutions, would be suitable for easy repeated installation and removal, had a low cost and could be implemented using readily available methods and materials.

This objective of the present invention, together with some of its additional advantages, is achieved by a device that is made and operates in accordance with the attached claims.

The present invention may take the form of a preferred, although not the only, embodiment, such as that described in detail and illustrated below by way of non-limiting example with reference to the accompanying drawings, in which:

Figure 1 is a simplified perspective view of the ring of the present invention together with a thermosensitive element sensor for use with said ring.

FIG. 2 is an enlarged view of the ring embodiment shown in FIG. 1.

Figure 3 is another perspective view of the ring shown in figure 2.

Figure 4 is a top view of the ring shown in the previous figures, as it is seen from a plane perpendicular to the axis of the ring.

Figure 5 is a side view of the ring shown in figure 4, in the view along arrow "V" shown in figure 4.

Fig.6 is a section of the ring shown in Fig.5, along the secant plane BB.

7 and 7a are, respectively, a perspective view of a method of using the device of the present invention and an enlarged view of a portion of this image.

Fig. 8 and Fig. 8a are perspective images of the device shown in Fig. 7 and Fig. 7a, respectively, in the next step of the aforementioned method of its application and installation.

Fig. 9 is a view showing a preferred method of mounting the apparatus of the present invention on a plastic polymer injection nozzle.

Fig. 10 is a view showing the device of Fig. 9 in its assembled state on the body of an injection nozzle with a heat-sensitive element arranged so that it can be attached to the ring.

11 is an image showing the next step of installing the device of the present invention, in the state when it is already firmly fixed to the nozzle.

12 is an enlarged section along the axis of the nozzle assembly of FIG. 11 in which the ring of the present invention is used.

As shown in the above figures, the device of the present invention contains a ring 8, the main features of which are illustrated in figures 1-6. This ring 8 is provided on its outer cylindrical surface with an opening 9 for receiving the terminal sensor 10 of the thermoelectric measuring device 11. Therefore, if, using any of the well-known methods, put said ring 8 on the outer cylindrical surface of the body, the temperature of which should be measured, then, in this way, a device configured to hold said terminal sensor 10 will be realized. As a result, the latter can be installed (with the possibility of removing) the exact position inside the ring and, optionally, said ring may, in turn, be set in the most favorable position to accommodate said terminal probe 10 into the most favorable position in relation to the zone whose temperature is to be measured.

In order to improve the accuracy and speed of response, the aforementioned hole 9 can be made through - from the outer to the inner surface of the ring so that the end sensor 10 can be advanced through it until it comes in direct contact with the outer surface of the hollow cylindrical body 1.

On the other hand, if the temperature characteristic is less sensitive to the smallest fluctuations, or if improved fixation of the sensor in the ring is preferable, it seems rational, as shown in Fig. 3, Fig. 4 and Fig. 6, so that the inner part 10A of said sensor 10 did not protrude from the inside of the ring; it is better that it extends in a direction substantially tangential to the ring itself, and preferably extends beyond the radius R emanating from the axis O of the ring perpendicular to the tangential direction D of said inner part 10A.

However, such a ring can create certain difficulties when donning it on the cylindrical body 1 due to obvious limitations of the elasticity of the material of the aforementioned ring. To overcome such a drawback and to facilitate putting the ring on the cylindrical body and removing it, a cross section 12 is made on said ring in order to allow the ring to expand elastically (Seeger ring) and thereby putting the ring on the cylindrical body and removing him lighter.

However, reliable fixation of the sensor 10 of the thermoelectric measuring device in the ring may not be properly ensured by simply inserting said sensor into said opening 9; to eliminate this drawback, the ring 8 is provided along the perimeter with a groove 15 open outwardly extending along the outer surface of the ring 8 approximately at the middle of its height, as is best seen, for example, in FIG. 2, FIG. 5, FIG. 7A and FIG. .9.

According to the present invention, the hole 9 into which the sensor 10 is to be inserted is therefore accessible, in its initial part, through two suitable profiles 17, 17A of the respective inner, mutually opposing surfaces of said perimeter groove 15.

However, the introduction of the sensor 10 into the ring even in this case may present some difficulties.

To eliminate this problem, at least one slot 38 is made on the inner side 28 of said ring 8, which is best shown in FIG. 2 and FIG. 3 along a limited part of the said inner side. This slot must be made in close proximity to said hole 9 and must pass through the entire thickness of the ring, i.e. should be connected to said groove on the opposite side of said ring 8.

The true reasons for this improvement will be better understood from the following description.

As shown in FIG. 7, FIG. 7A, FIG. 8, and FIG. 8A, in order to insert the sensor 10 into the hole 9, it is only necessary to insert the pointed end of a simple tool, for example, a screwdriver blade 29, between the edges 30, 31 formed opposite parts of said ring in an area in which one of said slots 38 is also made; if the screw is applied with the necessary force to the ring, the blade of this screwdriver 29 will be able to elastically push the said edges 30, 31 apart and, as a result, also increase the opening of the hole 9 into which the said temperature sensor 10 should then be inserted. temperature, as shown in Fig. 8 and Fig. 8A, the screwdriver 29 is removed, thereby allowing the above-mentioned edges to return to their free, i.e. normal position, again approaching one another, and, finally, reduce the opening of said hole 9 and tightly jam said sensor 10, which is already in its final position.

As mentioned earlier in this description, further advantages can be achieved if, as shown particularly clearly in FIG. 4 and FIG. 6, said opening 9, which is formed by said specific profiles 17, is oriented almost tangentially with respect to said ring 8. This circumstance in fact, it makes it possible to maximize the length at which the terminal sensor 10 is pinched and firmly held and, as a result, maximize the reliability and stability of the installation.

Fig. 9, Fig. 10 and Fig. 11 illustrate three consecutive steps of mounting the ring 8 of the present invention with its improvements described above on a cylindrical body 1, which is provided on a nozzle for injecting a thermoplastic polymer, during which the said ring is expanded so that to ensure the introduction of the sensor 10 into it, and then, after the introduction of the said sensor, the ring is released, allowing it to return to the free state.

Based on the explanations already given above in connection with this, and given the complete clarity of the accompanying drawings, specialists will not find any difficulty in understanding this embodiment or improving other components or modifications that have not been described in detail here.

Finally, FIG. 12 is an enlarged view of a section along the axis of a injection nozzle containing an internal through cavity 2, which connects a heated gate (not shown) and a cavity 5 of the shape through the rear inlet or inlet openings (not shown) and the front outlet channel 4.

In this figure, the hole 9 in ring 8 is clearly visible, into which a temperature sensor has not yet been inserted, as well as a typical arrangement of such a ring relative to said injection nozzle.

Claims (7)

1. A device configured to hold a heat-sensitive element containing a terminal sensor (10) mounted on the outer surface of a preferably cylindrical body (1), characterized in that the said device includes an elastic ring (8) configured to install it in contact with said outer surface (7), and in which a hole (9) is made for receiving said terminal sensor (10) of said heat-sensitive element. 2. The device according to claim 1, characterized in that the said elastic ring (8), preferably made of metal with high thermal conductivity, is divided by a cut (12), which increases the ability of the said ring to elastically expand and narrow. 3. The device according to claim 1 or 2, characterized in that in said elastic ring there is a perimeter groove (15) located on the outward facing surface of said ring, which therefore contains two mutually opposite edges (30, 31), and that said hole is accessible through two suitable profiles (17, 17A) of the respective inner surfaces of said edges. 4. The device according to claim 3, characterized in that at least one through slot (38) is made on the inner side (28) of said ring, preferably in accordance with the location of said opening (9), so that said edges (30, 31 ) have the ability to be partially extended in accordance with the location of the aforementioned at least one slot. 5. Device according to any one of the preceding paragraphs or any combination thereof, characterized in that said hole is oriented almost tangentially to said ring. 6. A device according to any one of the preceding paragraphs or any combination thereof, characterized in that the said hole (9) is a through hole that allows you to enter through it the said end sensor (10) until it comes in contact with the outer surface of the said body (1). 7. A nozzle for injecting a thermoplastic polymer containing a hollow cylindrical body (1), the inner cavity (2) of which is configured to allow said thermoplastic polymer introduced through the rear inlet (3) to flow through it, the injection head (6 ) located on the front end part of the said hollow cylindrical body and provided with a front exhaust channel (4), a thermoelectric measuring device (11) containing a terminal temperature sensor (10), and a device for installation novelty of said terminal sensor on the outer surface (7) of said hollow cylindrical body (1), characterized in that said hollow cylindrical body (1) is provided with a device for mounting said thermoelectric measuring device according to any one of the preceding paragraphs.

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