Screwed sight glasses

Screwed sight glasses

Screwed sight glasses that will never let you down. For decades. Under the toughest conditions.

We have a complete range of screwed sight glasses (similar to DIN 11851), which are used worldwide for safe process observation. Our screwed sight glasses meet the highest quality standards – according to our quality commitment “Swiss Excellence – Since 1936”.

Screwed sight glass fittings (also known as dairy pipe fittings) are used to observe processes in vessels, tanks, and pipes. They can be combined with our light fittings, wipers, and camera systems.

They are mainly used in the food sector (in dairies, breweries, and in the beverage industry) as well as in the pharmaceutical and medical sectors. Due to the screw cap, the sight glasses can be cleaned quickly. In addition, the high maximum operating temperature allows sterilization.

Requirements

Our portfolio consists of one product series. Each product is configurable according to your needs. This allows us to cover all common requirements. Here is an overview of the possibilities:

Sizes/ application:

Nominal size: DN 50 to DN 150
Free view: 50 to 150 mm
Maximum operating pressure: 6 bar
Maximum operating temperature: 150°C or 280°C (depending on the glass plate)
Materials:

Weld neck nozzle: 1.4301(7)/ 304(L), 1.4404/ 316L, 1.4435/ 316L
Slotted cover nut: 1.4301(7)/ 304(L)
Glass plate: Soda lime/ DIN 8902 (up to 150°C), borosilicate/ DIN 7080 (up to 280°C) (others on request)
Gaskets: PTFE, silicone, EPDM, Viton®, FPM/FEP-wrapped (others on request)
Approvals:

Gaskets with FDA approval, USP Class VI, regulation (EC) No. 1935/2024, etc. (others on request)
Machining/ special versions:

Slotted nut with with holes for light fittings and/ or camera systems
Weld neck nozzle with thick wall (old DIN standard)
Mechanical polishing up to Ra < 0.4
Weld neck nozzle with water outlet groove
Hydraulic pressure test on glass plate

Do you have further requirements? Please contact us at any time. We will be happy to find a solution together.

Why Max Müller?

Safety. In order to ensure the highest quality and full traceability, we only use flanges and glass plates that are made in Germany. Therefore, our products will never let you down.

Reliability. Founded in 1936, MAX MÜLLER has grown into one of the world‘s leading manufacturers of process observation equipment. Therefore, we will always be there for you.

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Product inquiry

We look forward to hearing from you. You can get in touch with us as follows:

Contact/ locations

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Data sheets/ downloads

			Data sheet
SSA

Add-ons

We have the following add-ons for screwed sight glasses:

Light fittings

High-quality light fittings and timers, made of stainless steel or aluminium, for either [Ex] or non-[Ex] applications

Wipers and motorized wipers

Central and lateral wipers for sight glasses and metal-fused sight glasses, manual or pneumatic, up to 16 bar and with vacuum

Spraying devices

For cleaning the inside of glass plates, with spray head in the center of the glass or on the side, for pressure or vacuum vessels

Add-ons for sight glasses

To extend the range of applications: Wipers and motorized wipers, spraying devices, protective grilles, mica plates, etc.

Camera systems

High-quality digital cameras, made of stainless steel, for either [Ex] or non-[Ex] applications