A bellow seal valve uses a metal bellows to seal the stem, so it does not leak steam or hot oil at the gland. It is the preferred isolating valve in modern boiler houses.
We list sizes 1/2, 1, 1 1/2, 2, 2 1/2, 3, 4 and 6 inch. Choose a size above for details.
What is a bellow seal valve?
A bellow seal valve is a globe valve that uses a welded metal bellows to seal the stem. The bellows is fixed to the stem and the bonnet, so fluid cannot reach the gland.
Ordinary packed valves leak a little steam over time. Therefore, bellow seal valves are used on steam, thermal oil and hazardous lines to stop leaks, save energy and reduce gland maintenance.
Further reading
- Globe valves explained (Wikipedia)
- Bellows and how they flex (Wikipedia)
- Steam and its industrial uses (Wikipedia)
Key terms explained
- Bellows
- A thin, pleated metal tube that flexes as the stem moves while staying sealed.
- Gland packing
- Soft rings around a valve stem that seal it. They wear and leak over time.
- Globe pattern
- A body shape where flow passes under a disc, good for regulating flow.
- PN rating
- Pressure Nominal: the pressure class in bar at reference temperature, such as PN16.
- Class 150 and 800
- American pressure classes. Class 800 is common for small forged steel valves.
- End connection
- How the valve joins the pipe: threaded, flanged, wafer, socket weld or clamp.
Features and benefits
- Metal bellows seal on the stem.
- Backup gland packing.
- Globe pattern for regulation and isolation.
- Flanged ends.
- Suits steam and thermal oil.
- Lower energy loss than packed valves.
Technical specifications
| Product | Bellow seal valve |
|---|---|
| Sizes | 1/2, 1, 1 1/2, 2, 2 1/2, 3, 4 and 6 inch |
| Pattern | Globe |
| Ends | Flanged |
| Supplier | Sparks Plumbing Experts Ltd, Nairobi |
Each size has its own page with sizing details. Choose a size above, then request a quote.
Applications of a bellow seal valve
- Boiler outlets. Isolates steam at the boiler.
- Steam mains. Isolates sections of steam distribution.
- Heat exchangers. Isolates steam to calorifiers and plate exchangers.
- Thermal oil systems. Isolates hot oil lines without leaks.
- Steam trap sets. Isolates traps for service.
- Dairy and food plants. Controls process steam.
- Laundries. Isolates steam to ironers and dryers.
- Hospitals. Isolates sterilizer steam supplies.
- Textile mills. Controls steam to dyeing machines.
- Breweries. Controls steam to coppers and tanks.
- Chemical plants. Isolates hazardous fluids without stem leaks.
- Tea and coffee factories. Controls drying and process steam.
How to choose and install
- Match size, pressure class and flange drilling.
- Choose body material for the steam pressure and temperature.
- Install with flow in the arrow direction.
- Support heavy valves so pipework is not strained.
- Open slowly to avoid water hammer.
Why choose Sparks Plumbing Experts
- Valves, flanges and gaskets togetherComplete a pipeline joint with matching valves, flanges, gaskets and bolts.
- Pressure-rated optionsMany items come in PN16, class 150 or class 300 ratings, so you can match the line.
- Stainless and carbon steelChoose stainless for corrosion resistance or carbon steel where it suits the service.
- Plant maintenance sparesKeep critical spares on hand for planned shutdowns and breakdowns.
- Visit or collect in NairobiOur store is at KCB Building, Enterprise Road, in the Industrial Area, so you can see parts before you buy or collect your order.
- Quotes your wayAsk for prices by phone, WhatsApp, email or the online quote form, whichever suits you on site.
- Over 1,600 products in one placeOur catalogue covers 55 categories, so one supplier can handle most of your parts list.
- Help choosing the right partSend a nameplate photo, a drawing or the old part, and we help you match size and specification.
- Single items or project quantitiesWe price a single replacement part just as readily as a full site order.
- Supply across East AfricaWe serve customers across Kenya, and we also supply buyers in Uganda and Tanzania.
Related products and accessories
Browse more: Valves · Boiler Accessories · Flanges · Gaskets.
Ordering from Sparks Plumbing Experts
We supply customers across Kenya, and we also serve buyers in Uganda and Tanzania. You can collect from our store at KCB Building, Enterprise Road, Nairobi, or ask us about delivery to your site. Send your quantities and specifications, and we will reply with prices and availability.
Request a Quote WhatsApp 0726 086 895
Frequently asked questions
Why choose a bellow seal valve?
It stops gland leaks, which saves steam and reduces maintenance.
Which sizes of bellow seal valve do you list?
We list 1/2, 1, 1 1/2, 2, 2 1/2, 3, 4 and 6 inch.
Is a bellow seal valve a globe valve?
Most are globe pattern with a bellows stem seal.
Can I mix sizes in one order?
Yes. Send a list with sizes and ratings.
What details do you need to quote bellow seal valves?
Tell us the size, end connection, pressure rating, body material and the fluid and temperature. A photo of the old part, a nameplate or a drawing also helps. Then call or WhatsApp 0726 086 895, or use the quote form on this page.
Do you deliver bellow seal valves outside Nairobi?
Yes. We supply customers across Kenya, and we also serve buyers in Uganda and Tanzania. Delivery or courier arrangements are agreed when you confirm the order.
How much does a bellow seal valve cost in Kenya?
The price depends on the type, size, material, pressure rating and quantity. Therefore, send your list with a quote request and we will reply with current figures.
What does PN16 mean on a valve?
It means a nominal pressure rating of 16 bar at reference temperature. At higher temperatures the allowed pressure is lower, so check the rating table.
Flanged or threaded: which do I need?
Threaded ends suit small sizes, usually up to 2 inch. Flanged ends suit larger sizes and make removal easier.
Can a bellow seal valve be repaired?
Packing and some internals can be serviced. A failed bellows usually needs the bonnet assembly replaced.
Why do steam plants use bellow seal valves?
They stop gland leaks, which saves steam and improves safety.
Are bellow seal valves suitable for thermal oil?
Yes, with the right body material and rating.
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