The Pit Furnace is a vertical batch heat treatment furnace, installed underground or semi-underground. It features a cylindrical heating chamber, large effective working space and outstanding temperature uniformity. The workpiece is hoisted vertically into the furnace for heating, suitable for long, heavy components.
A bell-type furnace is a vertical batch heat treatment furnace. The heating chamber is a cylinder set at or below floor level — which is why the arrangement is often called a pit furnace in the workshop — and the charge is lowered into it from above on a hoist. Every unit we build is a custom industrial furnace in the literal sense: chamber diameter and depth, charge weight and the process cycle are worked out from your parts rather than picked from a fixed size list. Workpieces hang through the heating cycle instead of lying on a hearth, and that is what makes the design suit shafts, long bars, tubes and heavy castings. Operation is periodic: charge, heat, soak, cool, discharge. That makes this a batch heat treatment furnace rather than a continuous line — it is the machine for a heavy or long batch you run again and again, not for an endless stream of small parts. Changxing Jiacheng Furnace has been an industrial furnace supplier and manufacturer since 2010, working from Changxing in Zhejiang, and this unit is built alongside our box, double-door and car-bottom furnaces.
Every furnace is fabricated, assembled and wired in our own workshop in Changxing before it is broken down for shipment. Because each one is a custom industrial furnace, the chamber, the control cabinet and the loading arrangement are trial-fitted together here rather than meeting for the first time on your site.
We work as an industrial furnace supplier to tube, casting, forging, aluminum and powder metallurgy plants, and the electrical, safety and HMI systems on export units are built to the standards those markets work to. Drawings, the control description and the documentation package travel with the machine.
The same workshop builds our box, double-door and car-bottom furnaces and the aluminum solution heat treatment furnace, so a plant that buys more than one type works with a consistent control platform and a single spare-parts route.
Vertical cylindrical chamber. Heating is arranged around a cylinder, so the load is worked on from every side instead of from a hearth underneath and a roof above. The round section keeps the wall close to the charge and leaves no corners for a long part to sit in; together with the high-precision temperature control system, it is what holds a stable, uniform chamber temperature through the soak. Ground space and load capacity. Because the chamber sits in the floor, the workshop keeps its floor area for handling, racks and storage, and the furnace takes headroom instead. Capacity follows the chamber rather than a hearth: it is designed for long and heavy workpieces, so a full batch of shaft parts or tube lengths goes in together. Routine maintenance is reached from the top of the chamber rather than from inside it, which keeps day-to-day checks short. - Deformation control on long parts. A shaft or tube hangs free for the whole cycle, so it is not resting on supports at temperature; the risk of sagging or bowing along its length is reduced. - Consistent results end to end. Because the part stands in the chamber instead of lying across it, the bottom and the top of a long workpiece pass through the same heating and cooling sequence. - One lift per batch. A full charge of long pieces goes in as a single lift rather than in sections, so the crane is committed for minutes instead of for a shift. - Hot work stays in one place. There is no bogie driving out of the chamber with a hot load on it; the charge is lifted vertically and stays over the furnace, which keeps the bay around it clear. - Batch economics without a continuous line. You get a large charge per cycle and low handling time per part without committing to a mesh-belt or roller-hearth installation.
| Chamber form | Vertical cylinder, at or below floor level |
| Chamber diameter and depth | Built to your workpiece envelope |
| Charge weight | Sized to your heaviest batch |
| Processes | Normalizing, tempering, annealing, stress relief |
| Typical workpieces | Shafts, long bars, pipes, castings, large mechanical parts |
| Loading | Top loading by crane or hoist, charge stood upright |
| Atmosphere | Optional controlled atmosphere system for anti-oxidation treatment |
| Working temperature and zones | Agreed against your process curve |
| Heating power | Matched to chamber volume and the heat-up rate you need |
| Lift or quench arrangement | Quoted separately where the process needs one |
| Floor opening and foundation | Formed with the chamber during installation |
Loading is a vertical lift, so the crane comes first: hook height above the floor, capacity at that height, and the sling or spreader used for your heaviest part. Chamber depth and the height of the rim above the floor both come out of that geometry, and a deep chamber under a low crane is far cheaper to solve on paper than on site.
The chamber is set into a prepared foundation with a working platform or surround at the rim, so operators can guide the charge and reach the top for maintenance. Plan the floor opening, the foundation and the crane approach together — the lift needs clear headroom and a straight run in to the rim.
Securing the batch belongs to the layout as well. Shafts usually stand on a base plate or in a charging basket, long bars are bundled and slung so they cannot shift during the lift, and the stacking height has to be agreed before the chamber is detailed, because it uses part of the depth you are paying for.
We build industrial heat treatment furnaces to order, so selection starts with your workpiece, material and output target rather than a catalogue number. Send us your drawings, process aim and site conditions; our engineers will compare the furnace types that fit, set the temperature zoning and handling arrangement around your parts, and confirm the layout with you before production begins. Custom work adjusts chamber dimensions and control configuration, while safety circuits and atmosphere safety components stay as designed. After delivery we remain reachable for start-up questions, fault finding and spare parts.
In workshop language the two names describe the same arrangement — a cylindrical chamber at or below floor level, loaded from above — and we build it under the bell-type name. If your internal specification is written around a pit furnace, send that document with the enquiry; as an industrial furnace supplier we regularly match chamber and control details to a customer's own standard.
The shaft is slung at two or more points, lifted vertically and lowered in standing on a base plate or in a charging basket at the bottom of the chamber. Because it travels and heats upright, it never sits on two supports with a free span between them. Tell us the slinging method and the crane hook height at enquiry — the lift gear uses chamber depth just as the workpiece does.
Yes. A controlled atmosphere system can be specified where the surface has to come out oxide-free, and the gas arrangement is matched to the material and to what the next operation expects. Describe the surface requirement rather than a gas name and we will configure the atmosphere side around it.
From the workpiece envelope and the batch. The longest part sets the depth, the widest charge sets the diameter and the heaviest batch sets the load rating; nothing is taken from a stock list. As an industrial furnace manufacturer we detail the chamber from your drawings, and we ask about slinging because the lift gear takes up height inside the chamber too.
Aluminum work is usually quoted on one of our aluminum furnaces rather than on this chamber. If the requirement is a heat treatment furnace for aluminum with a controlled quench transfer, it becomes a separate vertical unit built on the same top-loading layout. Send the alloy, temper and section and we will confirm which configuration fits.
The quotation moves to our aluminum solution heat treatment furnace. The heating side stays familiar — vertical chamber, top loading — but the cycle gains a transfer and quench stage, and that changes the arrangement around the furnace as much as the furnace itself. Alloy, temper and section thickness are the three details we need to size it.
