Double-layer glass feeding bottle and processing technology thereof

Abstract

The invention provides a double-layer glass feeding bottle and a processing technology thereof, and relates to the technical field of feeding bottles. The double-layer glass feeding bottle comprises a bottle body, and the bottle body is made of double-layer glass. The mounting sealing element is mounted on the bottle body in a sealing thread manner; the nipple is clamped on the mounting sealing piece in a sealing manner; the one-way valve assembly is fixedly installed at the bottom of the bottle body and used for introducing air outside the bottle in a one-way mode; and the control assembly is arranged on the lower portion of the bottom cover assembly and used for controlling the air inflow of the one-way valve assembly, and the air inflow of the control assembly has three states of full opening, half opening and full closing. Through the arranged control assembly, the air inflow of the one-way valve assembly can be controlled, and when the feeding bottle is not used, the air inlet of the one-way valve assembly can be adjusted to be in a fully-closed state, so that outdoor bacteria and dust can be prevented from entering the feeding bottle, and the feeding bottle is safer and healthier to use.

Description

Technical Field

[0001] The present invention relates to the technical field of baby bottles, and specifically to a double-layer glass baby bottle and its processing technology. Background Art

[0002] Glass baby bottles are very common in the market. Glass baby bottles have the following advantages: The glass material is relatively more environmentally friendly and does not release harmful substances; glass baby bottles are relatively easier to clean and disinfect, and will not leave odors or stains; glass baby bottles are usually more durable than plastic baby bottles and can be reused. A double-layer glass baby bottle is a baby bottle made of double-layer glass, which can keep the temperature of the liquid for a longer time.

[0003] In related technologies, such as an easy-lock double-stage anti-colic square baby bottle with the publication number of: CN 213431774 U, which is provided with a first one-way air return hole structure and a second one-way air return hole structure. Through the first one-way air return hole structure and the second one-way air return hole structure, the negative pressure value inside the baby bottle can be reduced during feeding, making feeding more labor-saving.

[0004] Another example is a baby bottle with the publication number of: CN102626370B, including: a bottle body, a bottle cap detachably installed at the upper end of the bottle body, an elastic nipple installed between the bottle cap and the upper end of the bottle body, a bottle bottom cover detachably installed at the lower end of the bottle body, an elastic sealing cover installed between the lower end of the bottle body and the bottle bottom cover, and an open ventilation device. When in the feeding posture, when the baby sucks the milk liquid, gas can enter the bottle body from the lower part of the bottle body to eliminate the pressure difference.

[0005] However, the ventilation device added to the baby bottle is directly exposed to the outdoor environment when not in use, which is prone to breeding bacteria. With the inflow of gas, bacteria and dust will be brought into the baby bottle, making it unsafe and unhealthy to use. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a double-layer glass baby bottle and its processing technology, which solves the problem that the ventilation device added to the baby bottle is directly exposed to the outdoor environment when not in use, is prone to breeding bacteria, and with the inflow of gas, bacteria and dust will be brought into the baby bottle, making it unsafe and unhealthy to use.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A double-layer glass baby bottle, including:

[0008] A bottle body, the bottle body is made of double-layer glass;

[0009] An installation seal, the installation seal is installed on the bottle body by sealing thread;

[0010] A nipple, the nipple is hermetically clamped on the installation seal;

[0011] One-way valve assembly, which is fixedly installed at the bottom of the bottle body and is used for unidirectionally introducing air outside the bottle;

[0012] Control assembly, which is arranged below the one-way valve assembly and is used for controlling the air intake of the one-way valve assembly. The air intake of the control assembly has three states: fully open, half open, and fully closed;

[0013] The control assembly includes an anti-slip washer, a shrapnel, and a control part. The anti-slip washer is fixedly installed on the lower surface of the bottle body. The shrapnel is fixedly installed on the anti-slip washer. The control part is eccentrically arranged on the shrapnel. By setting the control assembly, the air intake of the one-way valve assembly can be controlled. When not in use, the air inlet of the one-way valve assembly can be adjusted to the fully closed state, so as to avoid the entry of outdoor bacteria and dust, making the use of the feeding bottle safer and healthier; by setting the one-way valve assembly, air can be supplemented into the feeding bottle during feeding, reducing the difficulty of sucking milk, and the force-receiving head is designed in an arc shape, which can prevent milk powder from entering the air outlet, improving the cleanliness of the one-way valve assembly.

[0014] Preferably, the bottle body is composed of an upper half and a bottom cover assembly. The upper half is formed by fusing an outer bottle body and an inner bottle body. The lower part of the outer bottle body is provided with a body thread. A cavity for heat preservation use is provided between the outer bottle body and the inner bottle body. The top of the inner bottle body is integrally formed with a bottleneck. The bottleneck is provided with a neck thread. The bottom of the bottle body is provided with a sealing surface; the bottom cover assembly is hermetically and threadedly installed at the bottom of the bottle body; the bottom cover assembly includes a first sealing washer, a second sealing washer, and a bottle bottom cover. The bottle bottom cover is threadedly installed on the body thread. A cavity is provided inside the bottle bottom cover. The bottom of the bottle bottom cover is provided with a concave surface. An installation cavity for installing the one-way valve assembly is provided at the center of the concave surface. A sealing and mating part for placing the first sealing washer and the second sealing washer is provided at the upper part of the bottle bottom cover.

[0015] Preferably, the one-way valve assembly includes an integrally formed bottom sheet, a column body, and a force-receiving head. The force-receiving head includes an extended part and a shortened part. An air outlet that gradually contracts is provided between the extended part and the shortened part. An air inlet is provided in the middle of the bottom sheet. The air inlet is communicated with the air outlet. The air outlet is horizontally arranged.

[0016] Preferably, the control part includes a connecting head and a connecting rod. The connecting head is in threaded cooperation with the connecting rod. The upper end of the connecting rod is fixedly connected with a control piece. A fully closed piece and a half-closed piece are fixedly connected to the control piece. The lower end of the connecting head is fixedly connected with a spherical part and an operation convex block.

[0017] Preferably, it further includes a feeding bottle cap. The feeding bottle cap is clamped on the installation seal. A locking and sealing part is provided inside the installation seal. The bottom of the nipple can be clamped by the locking and sealing part. The locking and sealing part is in interference fit with the bottle body.

[0018] Preferably, the bottle body is integrally formed by an inner liner and an outer liner. The bottom walls of the inner liner and the outer liner are fused into one layer, and a cavity for heat preservation is provided between the inner liner and the outer liner.

[0019] A processing technology for a double-layer glass baby bottle, which is used to produce the above-mentioned double-layer glass baby bottle, includes the following steps:

[0020] Step 1: Coaxially insert two glass tubes with different radii and clean without scale, and use high-temperature fusion molding at 800°C - 1000°C to form a bottle body with the bottom walls fused into one layer and having a cavity.

[0021] Preferably, it further includes Step 2:

[0022] Perform high-temperature separation molding on the bottle body to obtain two parts that can be threadedly fitted.

[0023] Step 3: Anneal the bottle body at a temperature of 550°C - 650°C for 45 min - 65 min.

[0024] The present invention provides a double-layer glass baby bottle and its processing technology. It has the following beneficial effects:

[0025] 1. Through the control component provided in the present invention, the air intake of the one-way valve component can be controlled. When not in use, the air intake port of the one-way valve component can be adjusted to a fully closed state, thereby avoiding the entry of outdoor bacteria and dust, and making the use of the baby bottle safer and healthier.

[0026] 2. Through the one-way valve component provided in the present invention, air can be supplemented into the baby bottle during feeding, reducing the difficulty of sucking milk. And the force-receiving head is designed in an arc shape, which can prevent milk powder from entering the air outlet, improving the cleanliness of the one-way valve component.

[0027] 3. Through the bottle body and the bottom cover component provided in the present invention, during cleaning, the bottom cover component can be disassembled from the bottle body, thus facilitating the cleaning of the inner wall of the bottle body and making the cleaning easier. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the overall three-dimensional view of the present invention;

[0029] Figure 2 is the overall three-dimensional view of the present invention from the lower perspective;

[0030] Figure 3 is the overall disassembled sectional three-dimensional view of the present invention;

[0031] Figure 4 is Figure 3 the front view of;

[0032] Figure 5It is a sectional perspective view of the bottle body of the present invention;

[0033] Figure 6 It is a sectional perspective view of the bottom cover assembly of the present invention;

[0034] Figure 7 It is a partial sectional view of the bottom cover assembly of the present invention;

[0035] Figure 8 It is a perspective view of the control assembly of the present invention;

[0036] Figure 9 It is a perspective view of the lower view angle of the control assembly of the present invention;

[0037] Figure 10 It is an exploded view of the control part of the present invention;

[0038] Figure 11 It is a lower view of the whole of the present invention;

[0039] Figure 12 It is a perspective view of the one-way valve assembly of the present invention;

[0040] Figure 13 It is a perspective view of the lower view angle of the one-way valve assembly of the present invention;

[0041] Figure 14 It is a sectional view of the one-way valve assembly of the present invention;

[0042] Figure 15 It is a perspective view of the nipple and the mounting seal of the present invention;

[0043] Figure 16 It is a partial sectional view of the connection state of the nipple and the mounting seal of the present invention;

[0044] Figure 17 It is a sectional perspective view of the bottle body of the second embodiment of the present invention.

[0045] Among them, 1. Bottle cap; 2. Bottle body; 3. Bottom cover assembly; 4. Control assembly; 5. One-way valve assembly; 6. Nipple; 7. Installation seal; 201. Outer bottle body; 202. Inner bottle body; 203. Bottle neck; 204. Body thread; 205. Sealing surface; 206. Neck thread; 301. Bottle bottom cover; 302. Cavity; 303. Concave surface; 304. Installation cavity; 305. Sealing mating part; 306. Sealing washer one; 307. Sealing washer two; 401. Anti-slip washer; 402. Control part; 403. Spring piece; 4021. Connecting rod; 4022. Control piece; 4023. Full-sealing piece; 4024. Half-sealing piece; 4025. Connecting head; 501. Bottom piece; 502. Cylinder body; 503. Extended part; 504. Shortened part; 505. Air outlet; 506. Force-receiving head; 5011. Air inlet; 701. Locking and sealing part; 901. Inner liner; 902. Outer liner. Specific implementation mode

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0047] Embodiment 1:

[0048] As Figures 1-16 shown, the embodiment of the present invention provides a double-layer glass baby bottle, including:

[0049] The bottle body 2 is made of double-layer glass;

[0050] The bottle body 2 is composed of an upper half and a bottom cover assembly 3. The upper half is formed by fusing an outer bottle body 201 and an inner bottle body 202. A body thread 204 is provided at the lower part of the outer bottle body 201. A cavity for heat preservation is provided between the outer bottle body 201 and the inner bottle body 202. A bottle neck 203 is integrally formed at the top of the inner bottle body 202. A neck thread 206 is provided on the bottle neck 203. A sealing surface 205 is provided at the bottom of the bottle body 2;

[0051] Refer to Figure 1 , Figure 2 , Figure 3 , Figure 5, the outer bottle body 201 and the inner bottle body 202 are made of high borosilicate glass tube material. The high borosilicate glass tube has good impact resistance, bending resistance and compressive strength. Therefore, the bottle body 2 is more durable than ordinary glass, not easily broken when collided, safe to use. The sealing surface 205 is used to contact with the first sealing gasket 306 and the second sealing gasket 307 to improve the sealing strength between the bottle body 2 and the bottom cover assembly 3; the cavity between the outer bottle body 201 and the inner bottle body 202 can reduce the temperature transfer rate. Therefore, the bottle body 2 has a heat preservation function.

[0052] The bottom cover assembly 3 is installed at the bottom of the bottle body 2 by sealing threads; the bottom cover assembly 3 includes the first sealing gasket 306, the second sealing gasket 307 and the bottle bottom cover 301. The bottle bottom cover 301 is installed on the body thread 204 by threads. There is a cavity 302 inside the bottle bottom cover 301. There is a concave surface part 303 at the bottom of the bottle bottom cover 301. There is an installation cavity 304 for installing the one-way valve assembly 5 at the center of the concave surface part 303. There is a sealing cooperation part 305 for placing the first sealing gasket 306 and the second sealing gasket 307 at the upper part of the bottle bottom cover 301;

[0053] Reference Figure 4 , Figure 6 , Figure 7 , during cleaning, the bottle bottom cover 301 can be unscrewed from the bottle body 2, so that the bottle body 2 is exposed, which is convenient for cleaning the inner wall of the bottle body 2. It is convenient to clean and the operation is reliable; the concave surface part 303 is used to provide an operation space for the control component 4, which is convenient for operation; the cavity 302 is used to reduce the temperature transfer rate and improve the heat preservation performance of the bottle bottom cover 301. The center of the bottle bottom cover 301 is higher than the second sealing gasket 307. Therefore, the milk and water will not contact with the second sealing gasket 307, increasing the safety of feeding.

[0054] Install the sealing member 7. The installation sealing member 7 is installed on the bottle body 2 by sealing threads;

[0055] It also includes a milk bottle cap 1. The milk bottle cap 1 is clamped on the installation sealing member 7. There is a locking and sealing part 701 inside the installation sealing member 7. The bottom of the nipple 6 can be clamped by the locking and sealing part 701. The locking and sealing part 701 is in interference fit with the bottle body 2;

[0056] Reference Figure 4 , Figure 15 , Figure 16 , since the locking and sealing part 701 protrudes from the inner wall of the installation sealing member 7, when the bottom of the nipple 6 is put into the installation sealing member 7, it will be stuck, preventing the milk and water from flowing out from the gap between the nipple 6 and the installation sealing member 7, improving the sealing performance during feeding. At the same time, the locking and sealing part 701 can be mutually extruded with the bottleneck 203 of the bottle body 2, thus improving the sealing performance between the bottleneck 203 and the installation sealing member 7.

[0057] The nipple 6 is hermetically snap-fitted onto the mounting seal 7;

[0058] Reference Figure 15 , the nipple 6 is used for feeding infants, and its shape imitates that of the mother's breast to prevent infants from refusing to suck on the nipple 6.

[0059] The one-way valve assembly 5 is fixedly installed at the bottom of the bottle body 2 and is used for allowing air outside the bottle to enter unidirectionally;

[0060] The one-way valve assembly 5 includes an integrally formed bottom sheet 501, a column body 502, and a force-receiving head 506. The force-receiving head 506 includes an extended portion 503 and a shortened portion 504. An air outlet 505 that gradually contracts is provided between the extended portion 503 and the shortened portion 504. An air inlet 5011 is provided in the middle of the bottom sheet 501, and the air inlet 5011 communicates with the air outlet 505. The air outlet 505 is horizontally arranged;

[0061] Reference Figure 12 and Figure 13 and Figure 14 , the one-way valve assembly 5 can be made of an elastic material, such as silicone; the principle of one-way control is as follows: under the combined action of the liquid pressure and the force of the material itself, the extended portion 503 and the shortened portion 504 are pressed together and tightly attached to each other, causing the air outlet 505 to be in a closed state. When feeding, due to the sucking of the infant, the inside of the bottle body 2 is in a negative pressure state, the air pressure outside the bottle body 2 is greater than the air pressure inside the bottle body 2, and the milk bottle is in an inclined and inverted state, and the milk is far from the one-way valve assembly 5. Therefore, the force-receiving head 506 will not be subjected to the pressure of the milk, and the air outside the bottle body 2 will enter from the air inlet 5011 and then enter the bottle body 2 from the air outlet 505, making the air pressure inside the bottle body 2 balanced, facilitating the infant's sucking and making the sucking easier; among them, the air outlet 505 is horizontally arranged, and the extended portion 503 will provide a blocking effect on the air outlet 505. Therefore, when adding milk powder, the milk powder is not easily blocked at the air outlet 505, ensuring that the one-way valve assembly 5 can work properly.

[0062] The control assembly 4 is arranged below the one-way valve assembly 5 and is used to control the air intake volume of the one-way valve assembly 5. The air intake volume of the control assembly 4 has three states: fully open, half open, and fully closed;

[0063] The control assembly 4 includes an anti-slip gasket 401, a spring piece 403, and a control member 402. The anti-slip gasket 401 is fixedly installed on the lower surface of the bottle body 2, the spring piece 403 is fixedly installed on the anti-slip gasket 401, and the control member 402 is eccentrically arranged on the spring piece 403;

[0064] Reference Figure 8 and Figure 9, the anti-slip washer 401 is used to increase the friction between the feeding bottle and the placement surface when the feeding bottle is placed, improving the stability of the feeding bottle placement; the elastic piece 403 is used to provide elastic support for the control member 402, enabling the control member 402 to closely adhere to the bottom film 501; the control member 402 is used to adjust and use in three states: fully open, half open, and fully closed.

[0065] The control member 402 includes a connection head 4025 and a connecting rod 4021. The connection head 4025 is in threaded cooperation with the connecting rod 4021. The upper end of the connecting rod 4021 is fixedly connected with a control piece 4022. A fully closed piece 4023 and a half closed piece 4024 are fixedly connected to the control piece 4022. The lower end of the connection head 4025 is fixedly connected with a spherical part and an operation convex block;

[0066] Reference Figure 10 , during the control adjustment operation, the spherical part is used to contact the placement surface to provide support; the operation convex block is used to hold and operate the connection head 4025 with one hand. Specifically, the finger is used to push the operation convex block, so that the connection head 4025 rotates and the connecting rod 4021 rotates within the elastic piece 403. When the fully closed piece 4023 overlaps with the air inlet 5011 of the bottom film 501, the air inlet 5011 is in a fully closed state. At this time, external dust will not enter the air inlet 5011, thus ensuring the cleanliness inside the feeding bottle and being suitable for normal storage; when the half closed piece 4024 overlaps with the air inlet 5011, the air inlet 5011 is in a semi-closed state, which can reduce the air flow velocity of the external air flow entering the bottle. At this time, it is suitable for use when the sucking frequency of the baby is relatively high during the initial feeding, avoiding the risk of the baby choking on milk; when neither the fully closed piece 4023 nor the half closed piece 4024 overlaps with the air inlet 5011, the air inlet 5011 is in a fully open state, which is suitable for use when the sucking frequency of the baby is stable after feeding for a period of time, ensuring the smoothness of feeding.

[0067] Embodiment 2:

[0068] Reference Figure 17 , the difference from Embodiment 1 is that: the bottle body 2 is integrally formed by an inner liner 901 and an outer liner 902. The bottom walls of the inner liner 901 and the outer liner 902 are fused into one layer, and a cavity for heat preservation is provided between the inner liner 901 and the outer liner 902;

[0069] The feeding bottle provided by this embodiment is convenient for production, simple in structure, and low in manufacturing cost.

[0070] The present invention also provides a processing technology for a double-layer glass feeding bottle, which is used to produce the above-mentioned double-layer glass feeding bottle, including the following steps:

[0071] Step 1: Coaxially insert two glass tubes with different radii and free of dirt, and use high-temperature fusion molding at 800°C - 1000°C to form a bottle body 2 with a bottom wall fused into one layer and having a cavity;

[0072] Specifically: Select two glass tubes of preset sizes, clean and air-dry the two glass tubes to obtain glass tubes free of dirt; use clamps to hold the two glass tubes respectively, coaxially insert them into each other, and drive the two glass tubes to rotate synchronously under the action of an external drive source; use a flame to heat the two ends of the two glass tubes to 850°C, and use a mold and pliers to form the bottle body 2.

[0073] Step 2: Perform high-temperature separation molding on the bottle body 2 to obtain two parts that can be threadedly fitted;

[0074] Step 3: Anneal the bottle body 2 at a temperature of 550°C - 650°C for 45 min - 65 min. Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A double-layer glass milk bottle, characterized in that: include: A bottle body (2), wherein the bottle body (2) is made of double-layer glass; An installation seal (7), wherein the installation seal (7) is installed on the bottle body (2) through a sealing thread; A nipple (6), wherein the nipple (6) is sealingly engaged with the mounting seal (7); A one-way valve assembly (5), the one-way valve assembly (5) is fixedly mounted on the bottom of the bottle body (2) and is used for one-way passage of air outside the bottle; A control component (4), the control component (4) being arranged below the one-way valve component (5) and being used to control the air intake of the one-way valve component (5), the air intake of the control component (4) having three states: fully open, half open, and fully closed; The control assembly (4) comprises an anti-skid washer (401), a spring sheet (403) and a control member (402); the anti-skid washer (401) is fixedly mounted on the lower surface of the bottle body (2); the spring sheet (403) is fixedly mounted on the anti-skid washer (401); and the control member (402) is eccentrically arranged on the spring sheet (403).

2. A double-layer glass milk bottle according to claim 1, characterized in that: The bottle body (2) is composed of an upper half and a bottom cover assembly (3), wherein the upper half is formed by the fusion of an outer bottle body (201) and an inner bottle body (202), a body thread (204) is provided at the lower part of the outer bottle body (201), a cavity for heat preservation is provided between the outer bottle body (201) and the inner bottle body (202), a bottleneck (203) is integrally formed at the top of the inner bottle body (202), a neck thread (206) is provided on the bottleneck (203), and a sealing surface (205) is provided at the bottom of the bottle body (2); the sealing thread of the bottom cover assembly (3) is installed at the bottom of the bottle body (2); The bottom cover assembly (3) comprises a sealing gasket 1 (306), a sealing gasket 2 (307), and a bottle bottom cover (301); the bottle bottom cover (301) is threadedly mounted on the body thread (204); a cavity (302) is provided inside the bottle bottom cover (301); a concave portion (303) is provided at the bottom of the bottle bottom cover (301); a mounting cavity (304) for mounting a one-way valve assembly (5) is provided at the center of the concave portion (303); and a sealing mating portion (305) for accommodating the sealing gasket 1 (306) and the sealing gasket 2 (307) is provided at the top of the bottle bottom cover (301).

3. A double-layer glass milk bottle according to claim 1, characterized in that: The one-way valve assembly (5) comprises an integrally formed bottom plate (501), a column body (502) and a force-bearing head (506); the force-bearing head (506) comprises an extended portion (503) and a shortened portion (504); a gradually shrinking air outlet (505) is provided between the extended portion (503) and the shortened portion (504); an air inlet (5011) is provided in the middle of the bottom plate (501); the air inlet (5011) and the air outlet (505) are interconnected; and the air outlet (505) is arranged horizontally.

4. A double-layer glass milk bottle according to claim 1, characterized in that: The control member (402) comprises a connecting head (4025) and a connecting rod (4021); the connecting head (4025) is threadedly matched with the connecting rod (4021); the upper end of the connecting rod (4021) is fixedly connected to a control plate (4022); a full sealing plate (4023) and a half sealing plate (4024) are fixedly connected to the control plate (4022); and the lower end of the connecting head (4025) is fixedly connected to a spherical portion and an operating protrusion.

5. A double-layer glass milk bottle according to claim 1, characterized in that: The invention also comprises a milk bottle cap (1), wherein the milk bottle cap (1) is engaged with a mounting seal (7), wherein a locking seal portion (701) is provided inside the mounting seal (7), and the bottom of the nipple (6) can be clamped by the locking seal portion (701), and the locking seal portion (701) is interference fit with the bottle body (2).

6. A double-layer glass milk bottle according to claim 1, characterized in that: The bottle body (2) is made of an inner liner (901) and an outer liner (902) in one piece, the bottom walls of the inner liner (901) and the outer liner (902) are fused into one layer, and a cavity for heat preservation is provided between the inner liner (901) and the outer liner (902).

7. A double-layer glass milk bottle processing technology, used to produce a double-layer glass milk bottle as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Two clean and spotless glass tubes with different radii are coaxially inserted, and a bottle body (2) having a cavity and a bottom wall fused into a layer is formed by high-temperature fusion molding at 800° C. to 1000° C.

8. A double-layer glass milk bottle processing technology according to claim 7, characterized in that: Also includes: Step 2: Separate and mold the bottle body (2) at high temperature to obtain two parts that can be threaded together; Step 3: Annealing the bottle body (2) at 550°C-650°C for 45min-65min.

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