Home » Product » Mechanical Seals » Metal Bellow Mechanical Seals
Metal Bellow Mechanical Seal Manufacturer in Mumbai, India
Running a thermic fluid or hot oil pump where an elastomer secondary seal simply won't survive the temperature?
Ashish Seals India manufactures metal bellow mechanical seals for thermic fluid and hot oil applications — standard design, single mechanical seal, inherently balanced, inside mounted, independent of direction of rotation, for shaft diameters 25 mm to 100 mm, up to 10 bar and 350°C (product range BS14). We've been building mechanical seals in Mumbai since 2005.
A welded metal bellow does the job an elastomer secondary seal can't at high temperature: it flexes to absorb shaft movement without a dynamic O-ring, so there's nothing to harden, crack or hang up on the sleeve as the media gets hot. Because the bellow itself carries the torque, the design is inherently balanced and suited to high start-up torque — which is exactly the combination thermic fluid and hot oil circuits demand.
Types of Metal Bellow Mechanical Seals
Thermicfluid Application Metal Bellow Mechanical Seals
Built for the thermic fluid heating circuits used to control process temperature across corrugators, dryers, reactors and jacketed vessels. Standard design, single mechanical seal, inherently balanced, inside mounted, independent of direction of rotation, with a metal bellow instead of a dynamic O-ring — so the seal holds up through the continuous high-temperature cycling that thermic fluid systems put it through.
View Thermic Fluid Seal →
Hot Oil Application Metal Bellow Mechanical Seals
The same welded metal bellow construction, matched to hot oil pumps handling continuous high-temperature circulation. No dynamic O-ring means nothing to harden or crack as the oil cycles hot — and because the bellow is independent of torque transmission, the seal is well suited to the high start-up torque hot oil pumps often need.
View Hot Oil Seal →Both types share the same BS14 construction and specification envelope — the difference is the specific heating circuit each is matched to. If your duty falls outside standard thermic fluid or hot oil service, tell us the media and we'll confirm the right build.
Metal Bellow Mechanical Seal — Standard Specifications
Our standard BS14 range covers the following envelope. Duties outside this range are built to order — send your shaft diameter, pressure and temperature and we'll confirm.
| Parameter | Standard Range |
|---|---|
| Product code | BS14 |
| Shaft diameter | 25 mm to 100 mm |
| Pressure | Up to 10 bar (max.) |
| Temperature | –20°C to 350°C |
| Design | Standard design, single mechanical seal, inherently balanced |
| Mounting | Inside mounted |
| Rotation | Independent of direction of rotation |
| Secondary seal | Welded metal bellow — no dynamic O-ring |
| Torque transmission | Independent of torque transmission — suited to high start-up torque |
| Faces | Carbon, silicon carbide, [tungsten carbide] |
| Bellow material | [SS 316L / Hastelloy — selected for media and temperature] |
Why Choose a Metal Bellow Over an Elastomer Bellow?
At high temperature, an elastomer bellow or O-ring is the first thing to fail — it hardens, cracks, or simply can't take the heat cycling. A welded metal bellow solves the problem structurally:
That combination is what makes metal bellow construction the standard choice wherever a plant runs thermic fluid or hot oil circuits — media that would destroy an elastomer seal in a fraction of its expected life.
What We Need to Quote Your Seal
Metal bellow seals are matched to the pump and heating circuit, not sold as a single universal part. Send as much of this as you can — photographs of the existing installation fill most of the gaps.
| Parameter | What to Send | Why It Matters |
|---|---|---|
| Equipment type | Thermic fluid pump, hot oil pump, or other high-temperature circulation pump | Sets duty class and expected torque |
| Shaft / sleeve diameter | Actual measured diameter at the seal chamber | Sets bellow bore and internal dimensions |
| Pressure | Normal and maximum operating pressure | Must stay within the 10 bar standard limit, or flags a custom build |
| Temperature | Operating and maximum temperature, including start-up spikes | Confirms compatibility with the standard –20°C to 350°C envelope |
| Media | Thermic fluid or hot oil grade, corrosivity | Decides face and bellow material |
| Start-up torque | Typical and peak start-up conditions | Confirms the bellow design handles your torque profile |
| Existing seal | Model, drawing, photos, sample, failure history | Enables a compatible replacement |
| Order details | Quantity, delivery location, required date | Production and dispatch planning |
Industries We Serve
Metal bellow mechanical seals go wherever heat transfer fluids or hot oil run continuously at high temperature:
Why Buy from Ashish Seals India?
We've manufactured industrial sealing solutions in Mumbai since 2005, with the entire process under one roof:
Application-based seal selection by our own engineering team, matched to temperature and torque
Custom design and development, including reverse engineering from a worn sample
CNC and VMC machining, seal-face lapping [checked to light-band flatness]
Component inspection, assembly and testing before every dispatch
Standard BS14 range plus custom builds beyond the 25–100 mm envelope on request
[Repair and reconditioning of existing seals]
Frequently Asked Questions
What is a metal bellow mechanical seal?
A mechanical seal where a welded metal bellow — instead of an elastomer bellow or dynamic O-ring — flexes to absorb shaft movement. There's nothing to harden, crack or hang up on the sleeve, which is why it's the standard choice at high temperature.
What's the difference between the thermic fluid and hot oil versions?
Both share the same BS14 construction and specification envelope. The difference is the heating circuit each is matched to — thermic fluid systems used for process heating (corrugators, dryers, reactors) versus hot oil circulation pumps. Tell us your specific media and we'll confirm the right fit.
Why choose a metal bellow over an elastomer bellow or O-ring seal?
Elastomers harden and crack at sustained high temperature. A welded metal bellow doesn't have that failure mode — it flexes structurally instead, so it holds up through the continuous heat cycling thermic fluid and hot oil circuits put it through.
What temperature can a metal bellow seal handle?
The standard range covers –20°C to 350°C. Duties outside this envelope need a custom build — tell us your operating and peak temperatures and we'll confirm.
What shaft diameter and pressure range do you cover?
Our standard BS14 range covers shaft diameters 25 mm to 100 mm and pressure up to 10 bar. Larger or higher-pressure duties can be built to order.
Can this seal handle high start-up torque?
Yes — because the bellow is independent of torque transmission, the design is well suited to the high start-up torque common on thermic fluid and hot oil pumps.
Which industries use metal bellow mechanical seals?
Petroleum, petrochemicals, refineries, paper and corrugating, and any chemical process running jacketed reactors or heat-traced lines on thermic fluid or hot oil.
Which materials are used for the faces and bellow?
Carbon and silicon carbide for the faces as standard, with tungsten carbide available for harder duty. The bellow material is selected for your media and temperature — tell us the details and we'll confirm.
Is this seal balanced or unbalanced?
Inherently balanced — the bellow geometry itself provides the balance, without needing a separate balanced/unbalanced version like some spring-type seals.
Can you manufacture a replacement from an old seal or sample?
Yes. We regularly develop replacements from a worn sample, a dimensional drawing, or good photographs plus the equipment details and operating conditions.
What is the price of a metal bellow mechanical seal in India?
It depends on shaft diameter, materials and quantity — there's no fixed price list. Send your shaft diameter, temperature and media for a specific quotation.
How long does manufacturing take?
Standard BS14 sizes typically ship faster than custom builds. Share your required date with the enquiry and we'll confirm a lead time.
Do you supply outside Mumbai?
Yes — we supply across India [and export to the Middle East, Africa and Southeast Asia].
Request a Quote for a Metal Bellow Mechanical Seal
New thermic fluid or hot oil pump, or a seal that keeps failing from heat — send us the shaft diameter, operating temperature, pressure and existing seal details. Our engineers will confirm the right build, materials and any custom sizing, with a quotation to follow.