Circular sight glasses

Circular sight glasses

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

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

Circular sight glasses according to or similar to DIN 28120 and DIN 28121 allow the observation (and, in combination with a light fitting, the illumination) of the inside of stirring kettles, dryers, distillation columns, silos, centrifuges, tanks, mixers, reactors, evaporators, or other closed vessels.

The main objective is to observe and control reactions, process steps, filling levels, cleaning results, etc.

Requirements

Our portfolio consists of three 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:

Versions/ product series:

28120: For welding into or onto the vessel wall
28121: For screwing onto the pre-welding flange
DVG 28120: Double-glazed version of the 28120: Either with heating (to prevent fogged glass plates) or without heating (to prevent heat transfer, through additional air insulation between the two glass plates)
Nominal sizes/ nominal pressures:

According to/ similar to DIN 28120:
Nominal sizes: DN 50 to DN 200
Nominal pressures: PN 0, PN 2.5, PN 6, PN 10, or PN 16
According to/ similar to DIN 28121:
Nominal sizes: DN 40 to DN 200, or 1.5″ to 8″ according to ANSI (on request)
Nominal pressures: PN 10 or PN 25
Materials:

Flanges: 1.4541/ 321, 1.4571/ 316Ti, 1.4404/ 316L, RSt 37-2/ S235, HII/ RSt 45-8/ P265GH (others on request)
Glass plates: Soda lime/ DIN 8902 (up to 150°C), borosilicate/ DIN 7080 (up to 280°C) (others on request)
Gaskets: Klingersil® C-4400, PTFE, Viton, silicone, EPDM, Gylon®, graphite, Perbunan® (others on request)
Bolts/ nuts: Galvanized steel or stainless steel
Security tightening bolts: Galvanized steel or stainless steel
Approvals:

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

Flanges with radii
Flanges with O-ring groove
Flanges with drilled/ threaded holes for light fittings, camera systems, and accessories
Flanges with ground/ polished surfaces in contact with the product (up to Ra < 0.4)
Flanges with electropolishing
Flanges with paint/ powder coating
Flanges with marking/ labeling (milled or with laser)

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 components that are made in Europe. 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.

Company profile/ overview

Product inquiry

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

Contact/ locations

Contact form

Data sheets/ downloads

			Data sheet
28120
28121
DVG 28120

Add-ons

We have the following add-ons for circular 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