Type a line (DIN 7081 B 220, transparent 340, size IV, 220 x 34 x 17, DIN 7080 100x15), or pick the glass, the type and the size. Below, an offered glass can be checked against the one wanted.
On the type, size and glass alone: the material, gaskets and mica shields are checked separately, and the gauge maker’s drawing and the glass removed decide.
Flat level gauge glasses to DIN 7081 are made as reflex glasses (grooved on the liquid side) and transparent glasses (plain), and in two cross-sections, type A (30 mm wide) and type B (34 mm wide), both 17 mm thick; the length sets the size. Type a designation (“DIN 7081 B 220”, “reflex glass A 190”), a size number (“size IV”) or measured dimensions (“220 x 34 x 17”), and the finder gives the type, the size number and the length × width × thickness, draws the glass to scale, checks an offered glass against the one wanted and writes an RFQ line. A round sight glass to DIN 7080 is typed as diameter × thickness (“DIN 7080 100x15”).
This is reference data: the gauge maker’s drawing and the glass removed decide. A size is given only where two independent maker tables give the same value; where they differ, or only one table gives it, the size is left out. No pressure or temperature ratings are given: they depend on the glass material and the maker.
A reflex glass has grooves along its length, with faces at 90 degrees, moulded into the side that faces the liquid: the liquid shows dark and the vapour space bright, and the gauge has one glass. A transparent glass is plain on both faces, and the gauge has two glasses, one each side of the chamber. Mica shields are used with transparent glasses; for reflex glasses the makers differ: one says they are not used, a second recommends mica.
The letter gives the cross-section: type A is 30 × 17 mm, type B 34 × 17 mm, and both are made as reflex and as transparent glasses. The length sets the size: 0 is 95 mm, I 115, II 140, III 165, IV 190, V 220, VI 250, VII 280, VIII 320, IX 340 and X 370 mm (type B only). Gaskets and mica shields are separate items to order.
DIN 7080 covers round sight glass discs of borosilicate glass, sized by diameter × thickness, such as 100 × 15 mm. One diameter comes in more than one thickness, so measure both. Tubular gauge glasses are outside this standard and are not covered here.
| Size | Length L, mm | Type A, L × 30 × 17 mm | Type B, L × 34 × 17 mm |
|---|---|---|---|
| 0 | 95 | reflex | reflex |
| I | 115 | reflex, transparent | reflex, transparent |
| II | 140 | reflex, transparent | reflex, transparent |
| III | 165 | reflex, transparent | reflex, transparent |
| IV | 190 | reflex, transparent | reflex, transparent |
| V | 220 | reflex, transparent | reflex, transparent |
| VI | 250 | reflex, transparent | reflex, transparent |
| VII | 280 | reflex, transparent | reflex, transparent |
| VIII | 320 | reflex, transparent | reflex, transparent |
| IX | 340 | reflex, transparent | reflex, transparent |
| X | 370 | — | reflex, transparent |
A dash marks a size that is not in two independent maker tables. Size 0 (95 mm) is agreed as a reflex glass only: one maker alone lists a transparent glass of that length. Left out: the lengths 300, 400 and 420 mm (one maker only, and 300 has no size number); the thicker glasses (34 × 22 mm in one table, 21 mm thick in a second); the narrow glasses 20 × 12 and 25 × 15 mm and glasses 27.6 × 16.8 mm (one table each); size numbers in Arabic numerals (1 to 9 in one catalogue, 11 to 19 at one maker). A measured dimension is matched to a nominal one within 1 mm either way.
| Diameter D, mm | Thickness s, mm |
|---|---|
| 45 | 10, 12 |
| 50 | 10, 12 |
| 60 | 10, 12, 15 |
| 63 | 10, 12, 15 |
| 80 | 12, 15, 20 |
| 100 | 15, 20, 25 |
| 125 | 15, 20, 25 |
| 135 | 25 |
| 150 | 20, 25, 30 |
| 175 | 25, 30 |
| 200 | 20, 25, 30 |
| 250 | 25, 30 |
The pairs shown are those that two independent tables count as DIN 7080 sizes. Left out: 175 × 20 and 265 × 30 mm, which one table counts as DIN 7080 sizes and a second lists without that mark. The viewing diameter and the working pressure are not given: the pressure depends on the material, the maker and the seal.
The DIN 7081 flat level gauge glass tables of two makers (reflex and transparent glasses, types A and B) and the tables of a distributor for three more glass makers; the descriptions of reflex and transparent glasses by glass makers and level gauge makers; the DIN 7080 round sight glass tables of a sight glass fitting maker, a distributor and a further glass maker. Every figure on this page is in at least two of them; the text of DIN 7081 and DIN 7080 is not quoted.
In every maker table checked, the letter gives the cross-section of the glass, not whether it is reflex or transparent: type A is 30 mm wide and type B 34 mm wide, both 17 mm thick. Each type is made as a reflex glass and as a transparent glass, so a request names both: for example, reflex glass type B, 220 mm long.
A reflex glass has grooves with faces at 90 degrees moulded into the side that faces the liquid; the gauge has one glass, and the liquid shows dark against a bright vapour space. A transparent glass is plain on both faces; the gauge has a glass on each side of the chamber and is often lit from behind. They are made in the same sizes, but whether one can replace the other in a given gauge is for the gauge maker to say, so an offer of the other glass is marked for checking.
The maker tables checked number the lengths in Roman numerals: 0 is 95 mm, I 115, II 140, III 165, IV 190, V 220, VI 250, VII 280, VIII 320, IX 340 and X 370 mm (type B only). Numbers in Arabic numerals are not matched: one catalogue numbers the same glasses 1 to 9, a maker 11 to 19, and gauge bodies carry size numbers of their own. Give the length in mm when in doubt.
A size is shown only where two independent maker tables give the same length, width and thickness. Left out: 300, 400 and 420 mm (one maker only); size 0 as a transparent glass (one maker only); the thicker glasses for higher duty (22 mm in one table, 21 mm in a second); narrower glasses 20 and 25 mm wide; and round discs 175 x 20 and 265 x 30 mm, which one table counts as DIN 7080 sizes and a second does not.
None is given here. The limits depend on the glass material (borosilicate or aluminosilicate), the maker, whether a mica shield is fitted, the medium and the gauge itself, and the makers’ figures differ. Use the data of the glass maker and of the gauge maker for the duty.
DIN 7081, reflex or transparent, the type (A or B) or the width, the size number or the length, the dimensions length x width x thickness, the quantity, whether gaskets and mica shields are wanted, the maker and type of the level gauge and a photograph of the gauge and of the glass removed. For a round sight glass: DIN 7080, diameter x thickness and the sight glass fitting.
Finding the size is a check against maker tables, not the gauge maker’s drawing. Attach a photograph of the level gauge and of the glass removed, and Vessel Core checks them before an offer goes back.
