Home/Glass Lined Equipment Manufacturer
Glass lined equipment manufacturer — steel and glass, under one roof.
STAHL GLAS is the glass lined equipment brand of Govardhannathji Engineering Private Limited, manufacturing glass lined reactors, receivers, condensers, columns, valves and piping at Uttarsanda, Gujarat, India. Plate arrives at one end of the works and a tested, documented glass lined vessel leaves the other — fabrication, glass lining and inspection are all ours, and so is the enamel formulation.
Definition
What glass lined equipment is.
Glass lined equipment is steel process equipment whose wetted surface is faced with a layer of specially formulated glass, fused to the steel at high temperature. The steel carries the pressure, the weight and the nozzle loads. The glass carries the chemistry.
It is bought for three things at once, and few other materials give all three. It resists acids across the concentration range, including service where stainless and high alloy steels have a short and expensive life. It contributes nothing to the batch, which is why pharmaceutical production specifies it. And its surface stays smooth enough to clean properly, batch after batch.
The alternative — a vessel built throughout in an exotic alloy — costs a multiple of a glass lined one, and is still vulnerable to a change in the grade of feedstock that a lining would shrug off.
The term is written both “glass lined” and “glass-lined”, and the equipment is also called glass lined reactors, enamelled reactors, GL equipment or vitreous enamelled process equipment. They all describe the same thing.
- Finished lining thickness1 – 2.2 mm
- Dielectric strength20 – 30 kV/mm
- Specific weight2.5 g/cm³
- Compressive strength800 N/mm²
- Reactor standardDIN 28136, AE & CE
- Lining standardDIN EN ISO 28721
Manufacturing process
How glass lined equipment is manufactured.
Six stages turn plate into a glass lined vessel. Five of them are irreversible: once a coat is fired, the only way back is to strip the lining and start again. That is why the sequence below is run as a controlled process with a hold point at the end of every stage, not as a series of jobs handed between departments.
Steel fabrication
Plate is cut, formed and welded into shell, dished heads, jacket and nozzles. Internal welds are ground smooth and continuous and sharp corners are radiused, because a weld undercut or a sharp internal corner will not hold glass. Geometry decided here cannot be corrected later.
Surface preparation
The fabricated steel is sand and grit blasted, inside and out, to an even anchor profile. Glass keys into that profile mechanically as well as bonding to it chemically, so the quality of the blast largely decides the adhesion of everything fired on top of it.
Ground coat
A slip milled from frit is sprayed over the prepared steel, dried, and fired in an auto-control electric furnace. The ground coat is the bonding layer — it is formulated to hold to steel rather than to resist chemistry, and the cover coats hold to it in turn.
Cover coats
Successive cover coats are sprayed, dried and fired, each on its own controlled heating and cooling curve, until the lining reaches its finished thickness of 1 to 2.2 mm. This is where the chosen grade — SG-C, SG-CT, SG-P, SG-W or SG-R — actually goes on.
Inspection and testing
Coating thickness gauges measure the lining and a high-voltage spark tester finds any discontinuity in it. The steelwork behind it is checked by ultrasonic and magnetic particle inspection, by gamma-ray radiography, and by hydrostatic test.
Assembly, documentation and despatch
Agitator, drive, seal, baffles, thermowell and nozzle fittings are assembled into a ready-to-operate system, and the vessel is despatched with its material traceability per heat, test records and third-party inspection reports.
The firing is the part that needs the plant. Our two 1,400 kW auto-control electric furnaces, with 80 kW, 50 kW and 15 kW furnaces alongside them, are what allow a 40,000 litre vessel and a 63 litre pilot reactor to be fired to the same curve. See the glass lining and furnace capacity.
Scope of manufacture
What we manufacture as a glass lined equipment manufacturer.
A complete train rather than a single item: reactor, overhead condenser, receiver, scrubber column and the lined piping between them, all from one works and under one order number.
| Equipment | Range | Notes |
|---|---|---|
| Glass lined reactors | 63 – 40,000 L | DIN 28136 types AE and CE |
| Receivers & storage tanks | 160 – 40,000 L | Jacketed and un-jacketed |
| Agitation systems | — | Anchor, impeller, hydrofoil, CBRT |
| Condensers & heat exchangers | 2 – 10 m² | Disc and shell-in-shell type |
| Distillation & scrubber columns | 250 – 1,200 mm | — |
| Jacketed piping & fittings | To 500 NB / 600 NB | Including bottom outlet valves |
| ANF / ANFD | 630 – 5,000 L | Filters and filter dryers |
| Reglassing & relining | Any make | Not only our own vessels |
ASME-standard process equipment, GMP equipment, process piping and custom industrial structures are manufactured alongside the glass lined range. See the full product range.
Standards & quality
Standards, testing and documentation.
A glass lining cannot be judged by looking at it. Everything below exists so that the buyer does not have to take the lining on trust.
Design and construction
- Reactors to DIN 28136, types AE and CE
- Lining to DIN EN ISO 28721-1 and 28721-3
- ASME-standard fabrication where called for
- Material traceability per heat
In-house testing
- High-voltage spark testing of the complete lining
- Coating thickness gauges on every vessel
- Ultrasonic flaw detection and magnetic particle inspection
- Hydrostatic and pneumatic testing
Independent verification
- Gamma-ray radiography, with dark room and viewer on site
- Third-party inspection where the client or authority requires it
- R&D and QC laboratory for chemical resistance testing
- Full test and inspection records with the vessel
Technical data carries the thermal shock limits, heat transfer coefficients and corrosion tables behind these standards. Facilities and quality lists the equipment.
Before you order
What separates one glass lined equipment manufacturer from another.
Most suppliers will quote the same standard, the same volume and a similar price. These are the questions that actually distinguish them, and our answers to each.
Who owns the glass formulation?
Most glass lined equipment brands in India work to an enamel formulation owned by an overseas principal, so a change to suit an unusual medium needs somebody else’s approval. Our frit and enamel are developed in our own R&D laboratory, which is why a grade can be adapted to a customer’s chemistry. How our own glass came about.
How much of the job is subcontracted?
Fabrication, blasting, glass lining, testing and assembly all happen in one 26,000 m² works with 16,000 m² under crane and 1,500 KVA installed. Nothing leaves the site between stages, so nothing waits on somebody else’s schedule. See the works.
Is the grade matched to the duty, or to the catalogue?
Five grades exist because five different things go wrong. SG-C and SG-CT for chemical duty to 220 and 260 °C, SG-P where the lining must add nothing to the batch, SG-W where the surface must be seen, SG-R where the product sticks. Compare the grades.
What happens after the vessel is delivered?
A lining lasts decades if it is looked after, and the supplier who cannot reline is of limited use in year twelve. We reglass and reline vessels of any make, repair glass, spark test on site and assess damage. Services and reglassing.
Will the feedstock be asked about?
Fluoride at 20 ppm attacks glass, and technical-grade phosphoric acid is frequently fluoride-contaminated. Phosphoric acid also becomes more aggressive as it concentrates. A quotation raised without asking about either is a quotation raised blind. Corrosion resistance.
Can one supplier cover the whole train?
Reactor, condenser, receiver, column, lined piping, ASME-standard equipment, GMP stainless and the structures around them are all manufactured here — so the validation package covers one supplier, not six. Industries served.
FAQ
Frequently asked questions about glass lined equipment.
What is glass lined equipment?
Steel process equipment whose wetted surface is faced with a layer of specially formulated glass, fused to the steel at high temperature. The steel carries the pressure, the weight and the nozzle loads; the glass carries the chemistry. It resists acids across the concentration range, adds nothing to the batch and cleans easily, at a fraction of the cost of an equivalent vessel in exotic alloy.
How is glass lined equipment manufactured?
In six stages: steel fabrication; sand and grit blasting of the surface; a fired ground coat that bonds glass to steel; successive fired cover coats built up to 1–2.2 mm; thickness and high-voltage spark testing of the finished lining; then assembly, documentation and despatch. Each coat is fired in an electric furnace on its own controlled heating and cooling curve.
How thick is a glass lining?
A finished STAHL GLAS lining measures 1 to 2.2 mm, built from a ground coat and several cover coats. Dielectric strength is 20 to 30 kV/mm, which is what makes high-voltage spark testing a reliable way to find a discontinuity.
What standards do glass lined reactors follow?
Reactors are built to DIN 28136 in types AE and CE. The lining is specified and tested to DIN EN ISO 28721-1 and 28721-3. Where the client requires it, the steelwork is fabricated and documented to ASME practice, with material traceability per heat, radiography and third-party inspection.
What sizes of glass lined reactor can be manufactured?
From 63 litres for pilot plant up to 40,000 litres, with receivers and storage tanks to 40,000 litres, columns from 250 to 1,200 mm, jacketed piping to 500 NB, fittings to 600 NB, and ANF/ANFD from 630 to 5,000 litres.
How long does a glass lining last?
Decades, if the duty suits the grade and the vessel is looked after. Life is decided by thermal shock, mechanical impact and, in a few chemistries, fluoride in the feedstock — not by simple wear. Spark testing on a schedule catches a fault while it is still a repair rather than a reline.
Can a glass lined vessel be relined?
Yes, and not only our own. We reglass and reline glass lined vessels of any make, and also carry out refurbishment, retrofit, spares, glass repairs, on-site spark testing and damage assessment.
Does STAHL GLAS make its own glass?
Yes. The frit and enamel formulations are developed, tested and refined in our own R&D laboratory in Gujarat. That is unusual among glass lined equipment manufacturers in India, where the formulation is more often owned by an overseas principal — and it is what allows a grade to be adapted to a customer’s medium.
Which glass grade should be chosen?
SG-C for standard chemical duty to 220 °C, SG-CT to 260 °C, SG-P for pharmaceutical service free from heavy metal contamination, SG-W as a high-gloss reflective grade, SG-R where a non-stick surface is needed. The choice follows the medium, its concentration, the peak temperature and the cleaning cycle.
Where is STAHL GLAS located?
Near Gutal Crossing, N.H. No. 48, At. Uttarsanda, Ta. Nadiad, Dist. Kheda, Gujarat 387 370, India. Telephone +91 63585 84545, email info@stahlglas.in. Contact and directions.
Enquiries
Send us the duty. We will send back the engineering.
Medium, concentration, peak product and jacket temperature, batch volume and cleaning cycle are enough to start. We will come back with the grade, the type and the drawing — not just a price per litre.