Manhole sight glass type 325 PN 6/10/16 Flange mounting according to DIN EN 1092-1

Nuts Stud bolts Cover flange Glass cushion Sight glass Gasket Base flange Our round sight glasses type 320 are welded on or in a container wall to allow for observation or illumination of the inside of the container. A sight glass made of chemically highly resistant borosilicate glass DIN7080 is clamped between two high-quality stainless steel flanges and proven quality seals.  Beyond the definitions of DIN 28120, we also offer type 320 in special sizes of DN 250 and DN 300. These sizes, not specified in the standard, have also been constructed in accordance with DIN 28120.  Our sight glasses type 320 are made from high-quality stainless steel 1.4571 (316Ti), which our customers have appreciated for years. The glass material used is the tried-and-tested borosilicate glass according to DIN 7080 (or according to customer specifications).  The sealing of the fitting is done with flat seals tailored to your needs from a comprehensive range of materials. In addition to the common fiber seals, this also offers more demanding materials such as PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400, and many other brand seals. If the maximum operating temperature of borosilicate glass DIN 7080 does not meet your requirements, or if the process conditions pose a problem even for the highly resistant borosilicate glass, a mica protection disk specially adapted for the fitting offers additional protection against temperature and steam. FEP or Halar® coatings additionally protect the borosilicate glass from aggressive chemicals or alkalis. Like other sight glass fittings, type 320 can be equipped upon request with sight glass wiper type SGW and SWII, spray devices SVI, or lights. Cross-sectiondrawing Dimensions DN 25 40 50 80 100 125 150 200 250² 300² Da [mm] 115 150 165 200 220 250 285 340 395 445 Di [mm] 48 65 80 100 125 150 175 225 280 325 h1 [mm] 16 16 16 20 22 25 30 35 40 45 h2 [mm] 25 30 30 30 30 30 36 36 40 45 Glass-Ø [mm] 63 80 100 125 150 175 200 250 300 355 s (PN10) [mm] 10 10 12 15 20 20 25 30 45 45 s (PN16) [mm] 10 12 15 20 25 25 30 - - - Weight (PN 10) [kg] - 5,4 5,9 9,6 11,1 14,3 21,9 30,7 44,7 59,2 Weight (PN 16) [kg] 2,8 5,4 6,0 9,7 11,3 14,6 22,4 - - - 2) Similar to DIN 28120

The classic 'half moon' version for combined sight and light glassSuits Lumiglas Sight Glass Fitting, circular DIN 28120 or similarNominal dia: DN 50 to DN 200Power: depending on type 5 W to 15 W LEDMax. permissible ambient temperature measured at cable entry gland: 45°CConnection voltage see data shee

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.

The method of sizing:   DiameterD [mm] Widths [mm] Pressure[bar] Notes 24 10 150 disc special size 30 12 150 disc special size 15 200 disc special size 31,6 12,75 150 disc special size   Aluminosilicate 33 14 150 disc special size 33,12 15,95   Aluminosilicate 34 17 200 disc special size   Aluminosilicate 35 7 25 disc special size 40 10 40 disc special size 12 50 disc special size 44 10 40 disc special size 12 50 disc special size 45 10 40 acc. DIN 7080 12 50 acc. DIN 7080 50 10 25 acc. DIN 7080 12 40 acc. DIN 7080 55 6,5 6 disc special size 10 25 disc special size 60 10 16 acc. DIN 7080 12 25 acc. DIN 7080 15 40 acc. DIN 7080 20 95 disc special size 63 8 8 disc special size 10 16 acc. DIN 7080 12 25 acc. DIN 7080 15 40 acc. DIN 7080 65 10 12 disc special size 15 40 disc special size 70 12 16 disc special size 15 25 disc special size 75 12 16 disc special size 80 10 10 disc special size 12 16 acc. DIN 7080 15 25 acc. DIN 7080 20 40 acc. DIN 7080 86 12 10 disc special size 90 10 8 disc special size 92 10 8 disc special size 94 12 10 disc special size 95 10 6 disc special size 15 16 disc special size 100 10 7 disc special size 12 10 disc special size 15 16 acc. DIN 7080 20 25 acc. DIN 7080 25 40 acc. DIN 7080 105 15 16 disc special size 110 12,5 10 disc special size 20 25 disc special size 113 15 10 disc special size 115 15 10 disc special size 120 10 4 disc special size 15 10 disc special size 18 16 disc special size 125 15 10 acc. DIN 7080 20 16 acc. DIN 7080 25 25 acc. DIN 7080 30 40 disc special size 130 15 10 disc special size 135 15 8 disc special size 25 25 acc. DIN 7080 140 15 8 disc special size 150 10 2 disc special size 15 8 disc special size 20 10 acc. DIN 7080 25 16 acc. DIN 7080 30 25 acc. DIN 7080 160 20 12 disc special size 170 15 5 disc special size 20 10 disc special size 175 20 10 acc. DIN 7080 25 16 acc. DIN 7080 30 25 acc. DIN 7080 200 20 8 acc. DIN 7080 25 10 acc. DIN 7080 30 16 acc. DIN 7080 210 25 10 disc special size 250 20 4 disc special size 25 8 acc. DIN 7080 30 10 acc. DIN 7080 265 30 8 acc. DIN 7080   Note: if in the column Notes otherwise stated, borosilicate glass "extra hard" is used Round sight glasses are delivered separately or in a set with gaskets and mica shield. If you can not find the size - please contact us. Tolerances Diameter (d1):d1 ≤ 125 mm125 mm < d1 ≤ 200 mm d1 > 200 mm  ± 0,5 mm± 0,8 mm± 1,0 mm     Thicknes (s):s ≤ 20 mm s > 20 mm  + 0,5 mm / -0,25 mm+ 0,8 mm / -0,40 mm  Flatness (e):d1 ≤ 100 mm100 mm < d1 ≤ 150 mm 150 mm < d1 ≤ 200 mmd1 > 200 mm 0,05 mm0,08 mm0,12 mm0,15 mm    Parallelity (p):d1 ≤ 100 mm100 mm < d1 ≤ 200 mm d1 > 200 mm 0,20 mm0,25 mm0,30 mm Calculation of the glass thickness s - theoretical minimum glass thicknes [mm] dm => (d1+d2)/2 => average sealing diameter [mm]d1 - glass and sealing outside diameter [mm]d2 - sealing inside diameter [mm]p - permisible presure [bar] δbB - min. value of surface comressive stress [N/mm2] S - safety factor        Our offer includes sight glasses made of various materials, depending on environmental conditions (temperature, pressure, aggressive media). The properties of various glass materials are described on page Types of materials in chapter Our offer/Technical glass. The basic types of materials used for the manufacture of sight glasses are: soda-lime glass - widely available, cheap, working temperature up to 280 °C,  borosilicate glass - particularly suitable for use in aggressive environments (acids, alkalis, water vapor), working temperature up to 350 °C, aluminosilicate glass -  working temperature up to 660 °C, glass-ceramics - thermal shock resistant, working temperature up to 750 °C, quartz glass - with a broad spectrum light transmittance (from ultraviolet to infrared), working temperature up to 1100 °C, sapphire products - working temperature up to 2000 °C. To improve the strength, the machined glass is subjected to toughening and annealing. In order to increase the resistance of sight glasses on the aggressiveness of the working environment and in the use of high temperatures and pressures, additional use of mica shield is recommended. Mica disc working as shields are described here.  If you need this solution - please contact us. Round sight glasses are delivered separately or in a set with gaskets. Gaskets for sight glasses are described here. We offer sight glasses manufactured by leading brands such as: Spectraglass, Klinger or Maxos, which guarantees high quality and stability of parameters.   Safety precautions when using sight glass discs: Whenever a sight glass assembly has been taken apart it is urgently recommended in accordance with DIN 7080/ DIN 8902 that the glass disc and gaskets are replaced by new ones. That is particularly important in the case of pressure vessels and/or aggressive media. The following extract from DIN 7080/DIN 8902 text is verbatim: Sight glass discs may only be installed by personnel who have been informed fully about the following requirements: care in handling sight glass discs cleaning of recesses, sight glass discs, gaskets and other parts i. e. removal of foreign bodies (e. g. swarf), prior to installation/reassembly even tightening of retaining bolts Sight glass discs that have been removed after operating use must not be re used. Planned maintenance:Sight glass discs should be included in routine maintenance and periodically checked visually or using ultrasound wall thickness measuring means. In the event of damage, a glass disc must be promptly exchanged, with the plant first having been brought to a standstill. The service life of a sight glass, relative to the particular vessel in which it is mounted, should be established by regular and careful visual check of its condition.Caution: Completely demineralised water may dissolve glass – especially intensive periodical inspection required! Breakage of a sight glass:In spite of careful installation and recommended use, sight glass discs can, on rare occasions, suffer breakage through external influences. In order to prevent the entry of glass particles into products of a critical nature, e. g. foodstuffs, appropriate safety precautions should be taken by the plant manufacturer or user.  

Cross-sectiondrawing Dimensions Dimensions: Size     3 4 5 6 7 8 9 10 11 12 13 Nominal width  DN   50 80 100 125 150 200 250 300 350 400 500 Glass Ø  D [mm]    100 125 150 175 200 250 300 upon request Clear view  d1 [mm]    80 100 125 150 175 225 280 Wiping circle Ø  d2 [mm]    75 95 120 145 170 220 275 Glass thickness  S [mm]  Operating pressure max. PS [barü] Height  H [mm]                    116 15 8 5 4 3 2 / / 111 20 12 8 5 5 4 2 1 106 25 20 12 8 8 5 4 2 121 30 25⁴ 20 12 12 8 5 3 116 35 / 25⁴  21 15 11 7 4 111 40 / / 25⁴  20 14 9 6 106 45 / / / 25⁴  18⁴  11 7 111 55 ³   3) 55 mm on request4) higher pressures on request The sight glass wipers of type SGW are designed for the on-demand manual cleaning of glass plates in round sight glass fittings. They are suitable for applications under pressure and can also be easily retrofitted into existing sight glass fittings. Made of high-quality stainless steel, the wipers also meet the requirements in the food and drinking water sector. Various materials are available for the wiper blade: PTFE, silicone, or EPDM. The sight glass wipers are particularly effective in combination with the spray device SVI or SVIII.

Crews Cover flange Glass cushion Sight glass Gasket Base flange Product informationOur round sight glasses type 317 (PN 0) are welded onto or into a container wall to allow observation or lighting of the inside of the container. ACI sight glasses of type 317 were designed, based on DIN 28120, as a lightweight version for pressureless operation. A sight glass made of chemically highly resistant borosilicate glass DIN 7080 (or according to customer requirements) is clamped between two high-quality stainless steel flanges and proven quality seals. Type 317, unlike types 318 and 320, is not designed as a pressure-retaining construction, but as a pure sight opening. This makes type 317 significantly lighter and flatter than other commercially available sight glasses. Despite the lower requirements, our sight glasses of type 317 are made from the same high-quality stainless steel 1.4571 (316Ti) that our customers have appreciated for years. As glass material, the industry-proven borosilicate glass according to DIN 7080 (or according to customer requirements) is used. The sealing of the fitting occurs with flat seals adapted to your needs from a wide range of materials. In addition to the common fiber material seals, this also offers more demanding materials such as PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400, and many other branded seals. If the maximum operating temperature of borosilicate glass DIN 7080 does not meet your requirements, or if the process conditions pose a problem even for the highly resistant borosilicate glass, a mica protection cover specifically designed for the fitting offers additional protection against temperature and steam. FEP or Halar® coatings additionally protect the borosilicate glass from aggressive chemicals or alkalis. Like other sight glass fittings, type 317 can be equipped with a wiper type SGW, spray devices SVIII, or lamps upon request. Cross-sectiondrawing Dimensions DN 50 80 100 125 150 200 300 400 Da [mm] 140 165 190 215 240 290 370 450 Di [mm] 80 100 125 150 175 225 300 370 h1 [mm] 10 10 10 10 10 10 15 20 h2 [mm] 15 15 15 15 15 15 20 25 Weight [kg] 2,0 2,8 3,2 4,3 5,1 6,8 12,2 23,0