Portable Valve Grinding Machines for Globe & Safety Valves
Metals Kingdom Industry Limited supplies portable valve grinding machines for on-site and workshop maintenance of globe valves, safety valves, and related valve sealing surfaces. Our manufacturing experience in valve and pipeline maintenance equipment dates back to 1994.
This product series covers flat valve seats, conical valve seats, safety valve seats, valve discs, and other applicable sealing surfaces. Different models are available for small, medium, and large valve applications.
Why procurement teams specify this machine over a generic grinder
Buying the wrong seat-repair tool is expensive twice — once on the purchase order, and again the first time it fails to match the valve's actual seat geometry. Before shortlisting a supplier, most buyers are really comparing three things:
Can it handle both flat and conical seats without swapping to a different machine?
Is it rated for the actual seat diameter and valve class, not just the nominal pipe size?
Does the supplier provide selection support and configuration options, or does the buyer have to guess the right setup alone?
This is exactly why the product is searched under several names depending on the buyer's region and application — as an in-situ valve seat grinding machine, a valve reseating machine, a conical seat valve lapping machine, or a portable valve resurfacing machine. Whatever the term used in your RFQ, the underlying requirement is the same: restore a leaking seat to its original sealing profile, on-site, without removing the valve body.
Available Models
| Model | Grinding Range | Valve Size | Motor Power | Equipment Weight |
|---|
| M-100 | Conical valve seats: Φ20–65 mm
Flat sealing surfaces: Φ20–175 mm | DN20–150 (1″–6″) | 850 W | 27 kg |
| M-100A | Φ20–175 mm | DN20–150 (1″–6″) | 850 W | 22 kg |
| M-100C | Φ20–85 mm | DN20–80 (1″–3.2″) | 850 W | 24 kg |
| MJ-250 | Φ90–275 mm | DN80–250 (3″–10″) | 1,300 W | 38 kg |
| MJ-400 | Φ118–450 mm | DN100–400 (4″–16″) | 1,300 W | 80 kg |
What the machine actually does on-site
Grinds and laps flat globe valve seats to restore flatness and sealing contact
Grinds and laps conical globe valve seats, matching the original seat angle
Reseats safety and relief valve discs, restoring set-pressure accuracy that drifts once the seat is pitted
Supports wet lapping (abrasive paste) and dry grinding (abrasive paper) by changing the grinding disc, so the same machine adapts to Stellite-faced and standard steel seats
Runs on electric motor drive with adjustable speed, suited to coarse removal and fine finishing passes on the same seat
Fitted with replaceable grinding discs and centering tooling, so wear parts — not the whole machine — are what gets replaced over years of use
Configuration and Customization Options
Standard models cover the seat diameters and valve sizes most plants need, but valve geometry is rarely uniform across a fleet, especially on older or non-catalog equipment. We configure the following on request:
Non-standard seat angles for conical seats outside the common 30°–90° range
Extended output shafts where the valve bonnet, insulation, or piping layout limits access to the seat
Custom centering fixtures and mandrels for valves with irregular bore profiles or flangeless bodies
Alternate power supply and voltage configurations (110V/220V, single or three-phase) to match site electrical standards
Abrasive disc sets matched to seat material — standard steel, hardened steel, and Stellite-overlay seats each call for a different grit and bond
Air-driven or intrinsically safe drive options for hazardous-area sites where electric tooling is restricted
None of this needs to be specified from a catalog — send us the valve drawing or photo and working conditions, and we configure the machine to match, rather than asking you to adapt your maintenance procedure to a fixed product.
Model Selection Guide: How We Confirm the Right Configuration
Nominal valve size alone is not enough to select the right machine — the same DN rating can carry different actual seat diameters depending on valve design and manufacturer. Our selection process works in three steps:
You send us the basics — valve type, nominal size, actual sealing-surface diameter, flat or conical structure (and seat angle if conical), whether the repair target is the valve seat or the valve disc, required grinding depth, minimum installation clearance around the valve, a drawing or clear photo, and the power supply available on-site.
We confirm the model and configuration — matching seat diameter to grinding range, checking clearance against the machine's reach, and flagging any non-standard tooling needed (extended shaft, custom mandrel, alternate abrasive set).
We quote the complete working set — machine, centering tooling, abrasive discs sized to your seat material, and an operating manual, so nothing is missing when the machine arrives on-site.
This step matters most on safety and relief valves, where an undersized or oversized grinding head can leave the disc slightly out of flat — which shows up later as a set-pressure that drifts off spec even though the valve "passed" the repair.
Application Scenarios
Boiler safety valve annual reseating. Safety and relief valves on boiler headers typically require annual seat lapping to stay compliant with codes such as ASME BPVC. Doing this in-line on the header — rather than removing the valve — turns what would be a multi-day shutdown task into a repair completed in a single maintenance window.
Offshore and refinery hazardous-area repair. Platforms and refineries often require ATEX-rated or intrinsically safe tooling before any grinding equipment is allowed near a live process line. Valve bonnets on these sites are often large, so the machine needs a heavy-duty base and extended reach to clear the bonnet and still seat squarely on the sealing surface — this is a configuration point to raise before ordering, not after.
Chemical service globe valves with eroded seats. Globe valves throttling aggressive or abrasive media develop wire-drawing damage on the conical seat faster than on clean-fluid duty. Restoring the seat to a mirror finish resets both the seal and the flow-control (Cv) accuracy that drifts once the seat is pitted.
Stellite-faced high-pressure valve seats. Seats overlaid with Stellite for erosion resistance need diamond lapping paste rather than standard abrasive paper — a machine with wet-lapping capability and the right disc set handles this without switching equipment.
Field maintenance across a valve fleet with mixed sizes. Plants running both small control valves and large relief valves on the same site typically standardize on two models — one at the lower end of the range and one at the upper end — rather than one oversized machine for every job.
Industries Served
Power generation, petroleum and petrochemical processing, natural-gas transmission, chemical processing, metallurgy, shipbuilding, boiler maintenance, pressure-vessel maintenance, and water treatment.
Frequently Asked Questions
Can one machine handle both flat and conical seats? Within a model's rated range, yes — the grinding head and disc set are changed rather than the machine itself. Outside that range, we recommend the next model up or down based on your seat diameter.
Does the machine work on Stellite-overlay seats? Yes, using diamond lapping paste and the corresponding disc set instead of standard abrasive paper.
What's included with the machine on delivery? The base unit, centering tooling appropriate to your valve, a matched set of grinding/lapping discs, and an operating manual. Additional consumables and spare parts can be quoted alongside the initial order or stocked separately.
How is the correct model confirmed before ordering? Through the selection process above — valve drawing or photo, seat dimensions, and working conditions reviewed by our team before quotation, so the configuration is confirmed before you commit.
Can the machine be configured for hazardous-area or offshore use? Yes — intrinsically safe or air-driven configurations are available where site regulations restrict standard electric tooling.
Looking for a different valve type or repair method?
This page covers globe and safety valve seats specifically. If you're maintaining gate valve wedges and parallel seats instead, see our Portable Gate Valve Grinding & Lapping Machine. For larger valves better suited to bench-mounted repair rather than on-site work, see the Stationary Valve Grinding Machine. And once a valve is repaired, it still needs to be pressure-verified before returning to service — see our Valve Pressure Test Bench range, including the dedicated Safety Valve Test Bench.
Contact Us
Send your valve drawings, seat dimensions, and working requirements. Our team will confirm the right portable globe & safety valve grinding and lapping machine model and configuration — including tooling and abrasive selection — before you commit to an order.
