Glass ring tubular sight glass type 641 PN25/40

OD < 20 mm Outer diameter OD Wall thickness WT [mm] [mm] 3 0,7 4 0,8 5 0,8 6 1,0 1,5 7 1,0 1,5 8 1,0 1,5 9 1,0 1,5 10 1,0 1,5 2,2 11 1,0 1,5 2,2 12 1,0 1,5 2,2 13 1,0 1,5 2,2 14 1,0 1,5 2,2 15 1,2 1,8 2,5 16 1,2 1,8 2,5 17 1,2 1,8 2,5 18 1,2 1,8 2,5 19 1,2 1,8 2   20 mm ≥ OD < 40 mm Outer diameter OD Wall thickness WT [mm] [mm] 20 1,2 1,8 2,5 22 1,2 1,8 2,5 24 1,2 1,8 2,5 26 1,4 2,0 2,8 28 1,4 2,0 2,8 30 1,4 2,0 2,8 32 1,4 2,0 2,8 33 2,0 34 1,4 2,0 2,8 36 1,4 2,0 2,8 38 1,4 2,0 2,8 40 1,6 2,3 3,2 5   40 mm ≥ OD < 60 mm Outer diameter OD Wall thickness WT [mm] [mm] 40 1,6 2,3 3,2 5,0 42 1,6 2,3 3,2 44 1,6 2,3 3,2 45 5,0 46 1,6 2,3 3,2 48 1,6 2,3 3,2 50 1,8 2,5 3,5 5,0 7,0 9,0 52 1,8 2,5 3,5 54 1,8 2,5 3,5 55 5,0 56 1,8 2,5 3,5 58 1,8 2,5 3   60 mm ≥ OD < 100 mm Outer diameter OD Wall thickness WT [mm] [mm] 60 2,2 3,2 4,2 5,0 7,0 9,0 65 2,2 3,2 4,2 5,0 70 2,2 3,2 4,2 5,0 7,0 9,0 75 2,2 3,2 4,2 5,0 80 2,5 3,5 5,0 9,0 85 2,5 3,5 5,0 90 2,5 3,5 5,0 7,0 9,0 95 2,5 3,5 5,0 100 2,5 3,0 3,5 5,0 7,0 9   100 mm ≥ OD < 170 mm Outer diameter OD Wall thickness WT [mm] [mm] 100 2,5 3,0 3,5 5,0 7,0 9,0 105 3,0 5,0 110 3,0 5,0 7,0 115 3,0 5,0 7,0 120 3,0 5,0 7,0 9,0 125 5,0 9,0 130 3,0 5,0 7,0 9,0 135 5,0 7,0 140 3,0 5,0 7,0 145 5,0 150 3,0 5,0 7,0 9,0 155 5,0 160 5,0 7,0 165 5,0 7   OD ≥ 170 mm Outer diameter OD Wall thickness WT [mm] [mm] 170 5,0 7,0 9,0 180 5,0 7,0 9,0 190 5,0 7,0 200 5,0 7,0 9,0 215 5,0 7,0 9,0 225 7,0 9,0 240 9,0 250 5,0 7,0 9,0 270 5,0 7,0 9,0 300 5,0 7,0 9,0 315 7,0 9,0 325 9,0 10,0 350 5,0 365 7,0 400 6,0 415 7,0 420 9,5 430 6,0 440 7,0 450 7,0 8,0 460 8,5 465 7   While every attempt has been made to verify the source of the information, no responsibility is accepted for accuracy of data. Standard size range Large diameter tubes are sometimes called cylinders. The standard sizes of borosilicate tubes are given below.Choose the right outer diameter (OD), available wall thickness (WT), the required length (L) and the number of pieces, and then place your order by e-mail or contact form. The tubes are made of borosilicate glass 3.3. Detailed information about dimensions and tolerances of the borosilicate tubes we offer is available on the manufacturer's website, SCHOTT AG. NOTE! The standard tube length is 1500 mm, but we can supply tubes of different lengths. If you can't find correct size - contact us.   While every attempt has been made to verify the source of the information, no responsibility is accepted for accuracy of data.

Borosilicate glass 3.3 is one of the most commonly used and well-known types of heat resistant glass. Its high silica content and significant boron oxide doping make it exceptionally stable. The material can be milled, drilled, ground, and toughened without losing its structural integrity. These characteristics, combined with its borosilicate glass strength, make it suitable for both industrial and scientific uses. This type of boro glass performs reliably at elevated temperatures and is thermally stable up to 450 °C under continuous use. Its borosilicate glass temperature stability is a primary reason why it is frequently selected for laboratory setups and chemical reactors. Additionally, borosilicate glass 3.3 maintains excellent mechanical strength even in low-temperature conditions, with operational capability down to -196 °C, making it compatible with cryogenic substances like liquid nitrogen. For optimal safety, the temperature difference during thawing should not exceed 100 K; typically, operation down to -70 °C is recommended. Thanks to its outstanding chemical resistance, this borosilicate glassware is impervious to water, acids, alkalis, and most organic solvents. As such, it is extensively used in pharmaceutical manufacturing, scientific research, and chemical processing plants. The borosilicate glass properties of type 3.3 also make it a material of choice for borosilicate glass dishes, beakers, flasks, and other laboratory vessels. Suprax 8488, Pyrex, Boronorm & Borofloat Other types of borosilicate glass, such as Suprax 8488, Pyrex, and Boronorm, offer comparable borosilicate glass hardness and resistance to chemical and thermal stresses. Suprax 8488 is known for its consistency and is often used in technical lighting and optical applications. Pyrex, a widely recognized brand name, is commonly found in consumer borosilicate glass products like cookware and bakeware. These borosilicate glass dishes resist staining, cracking, and thermal deformation, making them ideal for use in ovens and microwave environments. Borofloat is another premium borosilicate glass variant designed for optical, display, and semiconductor applications. Its exceptionally smooth surface and excellent flatness, combined with its inherent borosilicate glass strength, make it indispensable in high-tech industries. Whether used in analytical instruments or microelectronics, Borofloat ensures consistent performance under stress. Applications of borosilicate glass The variety of borosilicate glass applications is as vast as its properties. It is widely used in: Laboratory borosilicate glassware (beakers, test tubes, measuring cylinders) Domestic borosilicate glass products (bakeware, cookware, coffee carafes) Pharmaceutical containers (vials, ampoules) Chemical processing equipment (reactors, pipelines) Optical components (lenses, filters) High-intensity lighting systems (projector lamps, automotive bulbs) Solar energy systems (glass tubing, photovoltaic module covers) Display technology (substrates for TFT and OLED displays) The heat resistance of glass in these applications is crucial for maintaining dimensional stability and ensuring longevity. For instance, borosilicate glass dishes used in kitchens can transition directly from freezers to ovens without risk of breakage due to the material’s thermal shock resistance. Why choose borosilicate glass? To summarize, borosilicate glass combines chemical inertness, high mechanical strength, and remarkable temperature resistance, making it one of the most versatile materials available. Its hardness, clarity, and processability further enhance its desirability across numerous industries. Whether you are selecting materials for a high-performance optical lens, a laboratory flask, or a heat-resistant baking dish, borosilicate glass delivers outstanding performance. We supply a full range of borosilicate glassware and custom borosilicate glass products tailored to your specific needs. With several types of borosilicate glass available, including borosilicate glass 3.3, Suprax, Borofloat, and Pyrex, our product line meets the highest standards in modern engineering and design. Composition SiO2  80 % B2O3  13 % Na2O  4 % Al2O3  2 % K2O  1 %   Standard thicknesses and tolerances Thickness Tolerance Thickness Tolerance 0,70 mm ±0,1 7,5 mm ±0,3 1,10 mm ±0,1 8,0 mm ±0,3 1,75 mm ±0,2 9,0 mm ±0,3 2,00 mm ±0,2 13,0 mm ±0,5 2,25 mm ±0,2 15,0 mm ±0,5 2,75 mm ±0,2 16,0 mm ±0,5 3,30 mm ±0,2 17,0 mm ±0,5 5,00 mm ±0,2 18,0 mm ±0,5 5,50 mm ±0,2 19,0 mm ±0,5 6,50 mm ±0,2 21,0 mm ±0,7   Properties: Density (@ 20 °C) 2 230 kg/m3 Bending strength 160 N/mm2 Surface compressive stress 100 N/mm2 Young’s modulus  64 GPa Poisson’s ratio 0,2 Hardness 5.5 Mohs, (470 Knopp, 580 Vickers) Thermal conductivity 1,2 W/(m K) Specific Heat 0,83 kJ/(kg K) Coefficient of linear expansion 3,3 ±0,1 * 10 -6 °C Index of refraction (@ 380 - 780 nm) 1,48  Softening point 815 °C Annealing Point 560 °C Max. working temperature: Non-tempered glass    - long term 450 °C  - temporary(< 10h) 500 °C Tempered glass    - long term 280 °C  - temporary(< 10h) 500 °C   Chemical properties: Hydrolytic Resistance   Acc.  ISO 719 (w 98 °C): class HGB 1    Acc.  ISO 720 (w 121 °C): class HGA 1  Alkali resistance   Acc. DIN 52 322 (ISO 695): class A2 Acid resistance   Acc. DIN 12 116: class 1 Electrical properties Volume resistance    at 25°C = 6.6 x 1013 Ω cm    at 300°C = 1.4 x 106 Ω cm Dielectric properties Electric Volume Resistivity         8,6 x 1013 Ωcm (at   25 °C)   1.4 x 106   Ωcm (at 300 °C) Dielectric dissipation fraction   38  10-4 (at 1 MHz, 20 °C) Dielectric constant εr   4.6 (at 1 MHz, 20 °C)   Optical properties Index of Refraction Spectral Transmission    λ = 587,6 nm nD = 1,4724    λ = 480,0 nm nF = 1,4782    λ = 546,0 nm nE = 1,4740    λ = 644,0 nm nC = 1,4701    Borosilicate glass 4.3 SiO2  78 % B2O3  10% Na2O  7 % Al2O3  3% ZrO2  2 %   Properties: Density (@ 25  °C) 2 280 kg/m3 Flexural strength 25 MPa Modulus of elasticity (Young’s) 67 GPa Poisson’s ratio 0,20 Thermal conductivity (@ 90 °C) 1,2 W/(m K) Specific heat 0,83 kJ/(kg K) Coefficient of linear expansion  (@ 20 °C - 300 °C) 4,3  * 10 -6 °C Index of Refraction (λ=587,6 nm) 1,484  Softening point 810 °C Annealing point 580 °C Glass temperature for density dPas 1013,0    560 °C10 7,6    800°C10 4,0   1200°C Working temperature:  - maximum 500 °C  - in a heavy duty conditions 280 °C   Chemical properties   Hydrolytic Resistance   Acc.   ISO 719 (@ 98 °C): class HGB 1    Acc.   ISO 720 (@ 121 °C): class HGA 1  Alkali resistance   Acc. DIN 52 322 (acc. ISO 695): class A2 Acid resistance   Acc. DIN 1776: class 1 Electrical properties Volume resistance    @ 25°C = 6.6 x 1013 Ω cm    @ 300°C = 1.4 x 106 Ω cm Dielectric properties @ 25° C and 1 MHz:    Dielectric constant εr=4,6    Dielectric loss factor tgδ =1,4x10-2   Optical properties Index of Refraction Spectral Transmission    λ = 587,6 nm nD = 1,4816    λ = 480,0 nm nF = 1,4869    λ = 546,0 nm nE = 1,4831    λ = 644,0 nm nC = 1,4802      While every attempt has been made to verify the source of the information, no responsibility is accepted for accuracy of data. In this text you will learn about borosilicate glass: properties, strength, thermal and chemical resistance, types, and applications in laboratory, industrial, optical, and domestic environments. Properties and applications of borosilicate glass Borosilicate glass is a specialized type of glass that contains significant amounts of silica (SiO₂) and boron trioxide (B₂O₃), making it highly resistant to thermal shock and chemical corrosion. Known for its durability, clarity, and stability under temperature fluctuations, borosilicate glass is widely used in laboratory, industrial, and domestic applications. Often referred to as boro glass, this material exhibits unique performance characteristics that set it apart from conventional soda-lime glass. One of the key properties of borosilicate glass is its exceptional resistance to temperature changes. This heat resistant glass can withstand both extremely high and low temperatures, making it suitable for demanding environments. The borosilicate glass temperature resistance allows it to endure up to 450 °C during long-term use and down to -196 °C when in contact with substances like liquid nitrogen. These attributes are a result of its low coefficient of thermal expansion, which ensures the glass does not crack or deform when exposed to rapid temperature changes. Another significant feature is the borosilicate glass strength and durability under mechanical and thermal stress. The typical hardness of borosilicate glass is rated at 5.5 on the Mohs scale, with corresponding values of 470 on the Knoop scale and 580 on the Vickers hardness test. These measures confirm the high borosilicate glass hardness, making it ideal for situations that demand both precision and resilience. The versatility of borosilicate glass arises from the ability to modify its chemical composition by incorporating various metal oxides. These variations result in a broad range of borosilicate glass products, each tailored for specific applications. The boron oxide content in the glass batch—i.e., the mix of raw materials used in the production process—plays a crucial role in defining not only the borosilicate glass properties, but also the behavior of the molten glass during manufacturing. At our facility, we offer several types of borosilicate glass, including: Borosilicate glass 3.3 (DIN 7080) Borosilicate glass 4.3 Suprax 8488 Pyrex Boronorm Borofloat Each of these borosilicate glass types features unique compositions and is suited for various borosilicate glass applications, from laboratory glassware and cookware to high-performance optics and chemical equipment. To work in an environment of steam and hydrostatic applications we offer borosilicate glass 4.3. Resistance to chemicals and thermal expansion permit the use of a high level of hardening, so that the glass are characterized by high resistance to thermal shock. Is suitable for operation at low temperatures. Can withstand the temperature to about -196 °C (is suitable for use in contact with liquid nitrogen). During thawing ensure that the temperature difference does not exceed 100 K. In general is recommended for use down to -70 °C.

Nuts Flange Threaded rod Borosilicate glass cylinder Gasket The ACI tubular sight glass type 620 offers a complete 360° view of the process medium through a borosilicate glass cylinder. Encased between two high-quality flanges made of stainless steel or carbon steel, it enables comprehensive visual control of your system. The standard version is equipped with flanges made of stainless steel 1.4571 (316Ti) – a material known for its excellent corrosion resistance and durability in industrial applications. For less demanding applications, a variant with flanges made of P265GH is also available. In addition, special materials such as Hastelloy®, duplex steels, or other high-performance alloys can be realized upon request. The glass tube is made of industrially tested borosilicate glass 3.3 according to DIN ISO 3585. It impresses with high temperature and chemical resistance as well as very good optical properties. The sealing is done with individually selectable flat seals from a wide range of materials – from classic fiber material seals to high-quality special materials like PTFE (Teflon®), NBR, novaphit® MST-XP, or KlingerSil® C4400. This allows the gasket to be optimally adapted to the medium, temperature, and pressure. In nominal sizes up to DN 50, the tubular sight glass type 620 is designed for operating pressures of up to 16 barg. Thanks to the precise coordination of flange, gasket, and glass, the fitting is almost dead space-free, making it suitable for hygienically demanding processes. For areas with increased mechanical hazards – e.g., when installed under walkways – we recommend optional impact protection covers. These reliably protect the glass tube from falling objects and minimize the risk of unplanned failures or damage. Cross-sectiondrawing Dimensions DN 15 20 25 32 40 50 65 80 100 125 150 200 250⁴ 300⁴ K [mm] 65 75 85 100 110 125 145 160 180 210 240 295 350 410 DF [mm] 41 54 64 74 84 98 118 134 154 184 208 264 320 370 D [mm] 95 105 115 145 150 175 195 200 225 250 295 345 400 460 PS [barg] 16 16 16 16 16 16 10 10 10 8 7 5 4 4 Number of bores and diameter according to DIN EN 1092-1 - PN10/16 (from the nominal size DN 200 only PN 10) 4) Special construction, only upon prior request. Other sizes, lengths, and flange standards available upon request  

V-flange type 11 according to DIN EN 1092-1 Gasket Glass ring tubular sight glass type 640 Gasket V-flange type 11 according to DIN EN 1092-1 The intermediate flange tubular sight glass type 640 is a compact solution for visual process monitoring of media in pipelines. The design as an intermediate flange model allows for space-saving installation between flanges in accordance with DIN EN 1092-1. With a working pressure of up to 16 barg, the type 640 is suitable for a variety of industrial applications. The compact design allows for subsequent integration into existing systems – even with limited space availability. Even with larger nominal sizes, operating pressures over 16 barg can be realized, offering additional flexibility. The standard version made of thermally hardened borosilicate glass is designed for operating temperatures up to 280 °C and offers high resistance to thermal and chemical stress. Cross-sectiondrawing Dimensions DN 10 15 20 25 32 40 50 65 80 100 125 150 200 250 300 350 400 450 500 Di [mm]  14 18 22 29 38 44 55 71 83 108 132 160 208 260 310 341 392 443 494 Da [mm] 40 45 58 68 79 88 102 122 138 158 188 212 268 320 378 430 482 532 585 Weight² ⁴ 0,13 0,16 0,27 0,36 0,46 0,56 0,71 0,94 1,16 1,27 1,71 1,85 2,73 3,28 4,41 6,2 7,1 7,8 8,9 Weight³ ⁴ 0,07 0,08 0,13 0,18 0,22 0,27 0,34 0,46 0,58 0,62 0,83 0,9 1,32 1,61 2,17 3,18 3,64 4,02 4,55 PS ² ⁵  16 16 16 16 16 16 16 16 16 16 16 16 16 10 10 10 10 10 10 PS ³ ⁵ 16 16 16 16 16 16 16 16 10 10 10 8 8 8 6 6 6 6 6 ² Borosilicate glass³Acrylic glass⁴Weight in [kg] for L = 50 mm⁵max. operating pressure in [barg]Other materials, sizes, lengths and flange standards on request