En-Masse Conveyor Installation & Commissioning: The Factory Procedure, Step by Step

An en-masse (buried scraper) chain conveyor does not carry material on a belt — it drags a solid plug of material through a closed steel casing with scraper bars mounted on a chain. That single difference changes everything about installation. There is no belt to train, but there is a chain that must run in the correct direction inside a casing that must be straight to within a few millimetres, with side clearances that prevent the scrapers from rubbing and a tension setting that keeps the chain on its guide rails. This guide is the installation and commissioning procedure our service engineers use in the field, condensed from the Tianyi en-masse conveyor training manual. It covers preparation, the erection sequence, centreline and support tolerances, casing assembly and straightness, scraper chain installation and tensioning, inlet and drive installation, the no-load and load trials, and the maintenance regime after handover. For the equipment itself, see our en-masse chain conveyor page.

1. Why En-Masse Conveyor Installation Is Different

On a belt conveyor, the belt is both the carrying surface and the traction element, and most installation effort goes into keeping it centred. On an en-masse conveyor, the casing is the carrying surface and the chain is the traction element. The material is not resting on a moving belt; it is being pushed and dragged as a continuous plug between the scrapers. The clearances around the chain, the straightness of the casing and the alignment of the head and tail wheels therefore decide whether the machine runs quietly for years or wears itself out in months.

The installation faults that show up in the first weeks are consistent:

• Chain rubbing or jamming: casing sections assembled out of sequence, flanges misaligned, or a casing that is not straight.
• Chain climbing or jumping at the head wheel: chain installed in the wrong direction, or insufficient tension.
• Scraper bars bent or broken: a flange joint protruding into the material path, or hard foreign material entering the casing.
• Excessive noise: loose chain pins, a worn chain joint, or debris left inside the casing at handover.
• Premature chain and wheel wear: head and tail wheels not aligned, or shafts not parallel.

2. Before Erection: Packing List, Layout Drawing, Foundation and Crew

Most installation rework starts before the first bolt is tightened. The manual is explicit about the preparation stage because an en-masse conveyor cannot be corrected later by adjusting an idler — the error is built into the casing.

• Unpack and check against the packing list. Count every component, classify it, and inspect for transport damage. Identify the head section, tail section, intermediate and transition sections, drive unit, chain, covers and accessories before erection begins.
• Measure the foundation and the supporting structure. Compare the actual dimensions and elevations with the installation layout drawing. Resolve any discrepancy before the equipment is placed — not after it is welded down.
• Confirm the foundation has cured. The concrete foundation should be poured at least 20 days before formal installation. It must support the conveyor reliably, without sinking or deforming because the footing is too small, and it must give the machine enough stability in operation.
• Prepare the tools and materials. Spanners, a welding machine, oxy-fuel cutting equipment, wire rope, fine steel wire for the centreline, levels, shims and gaskets.
• Assemble the right crew. Installation requires fitters, welders, riggers and electricians. Chain handling and casing placement are rigging work, not improvised manual lifting.

3. The Erection Sequence: From Centreline to Wiring

The order in the manual is deliberate. Each step assumes the previous one has been completed and checked, and doing them out of order is how casings end up stressed and chains end up twisted.

1. Mark the foundation centrelines. The longitudinal centreline is set from the plant process datum and from adjacent equipment; the transverse centreline is set the same way.
2. Check the embedded foundation. Verify the anchor plates, pockets and elevations against the foundation drawing, and correct anything that is out of position.
3. Install the supports. Head support first, then the intermediate supports, following the layout drawing. Measure every embedded part before fitting, because civil works and support fabrication both carry tolerance.
4. Assemble the casing. Head, transition, intermediate and tail sections, in the numbered order marked on each section. Flanges are initially bolted loose with gaskets in place, so the line can still be adjusted.
5. Install the scraper chain. Lower run first, then the upper run, with the correct orientation relative to the head wheel rotation.
6. Install the inlet and the covers. The inlet is usually cut and welded on site; every cover needs a gasket.
7. Install the drive unit. Motor, reducer and transmission, aligned to the head wheel shaft.
8. Install the safety devices. Chain guard, chain-break alarm and blockage alarm where specified, and the water pipes for a water-cooled casing.
9. Run the electrical wiring. From the local control box to each electrical component, following the electrical schematic, with every cable numbered and recorded.
10. Clean the casing. Remove tools, welding slag, debris and water before commissioning.

4. Centreline and Support Tolerances

The support frame is the reference for everything above it. If the supports are out of line, the casing will be out of line, and no amount of chain adjustment will fix it.

4.1 Setting out the centrelines

4.2 Support installation tolerances

After the supports are checked and accepted, touch up the paint. The paint type and colour must match the original components.

5. Casing Assembly and Straightness

The casing is the heart of an en-masse conveyor. It guides the chain, contains the material and carries the scrapers. Each section leaves the factory with a match-marked sequence number; the sections must be assembled in that order and in that direction. Sections must not be swapped or reversed.

5.1 Assembling the sections

• Place the gasket between each pair of flanges, bring the sections together and fit the bolts hand-tight only. The line must still be able to move while it is aligned.
• Remove the covers and stretch a 1 mm steel wire along the head and tail wheel centrelines, at an adjustable height. This wire is the machine centreline and must coincide with the marked longitudinal centreline.
• Use the wire to check that the guide rails in each casing section are centred, and move the sections until the tolerances below are met.

5.2 Casing symmetry tolerance

The symmetry of the head, tail and intermediate casing side walls about the conveyor's longitudinal centre plane must meet the values in the table.

5.3 Flange joints

• The internal joint between adjacent casing flanges must be flat, tight and misaligned by no more than 2 mm. The inner wall and the guide rails must not step up, down, left or right.
• The casing is allowed to sit slightly lower in the direction of chain travel — the downstream section lower than the upstream section — so that the scrapers cannot catch on a lip. It must never sit higher.
• The head and tail wheels must be centred on the casing and their shafts must be parallel, otherwise the chain will run to one side.

5.4 Welding and final tightening

Once the casing is aligned to the wire, weld the head section firmly to the head support first. The head casing carries the highest load in the machine and must not move or loosen in service. Then tighten the flange bolts between the transition, intermediate and tail sections, and weld or clamp those sections to the intermediate supports. The whole line must not swing left or right during this stage. Remove the wire only when the line is fully fixed.

5.5 Overall straightness

Measure straightness as follows: find the symmetrical centre points A at the head and B at the tail, stretch a fine wire L1 along one side of the conveyor (it must be able to move vertically), and set the wire at a distance S from the A–B line, where S = half the casing width + 80 mm. Measure the maximum and minimum perpendicular distances from the wire to the outside of the casing. Straightness = Δmax − Δmin.

The head must be firmly fixed to the foundation or support. The intermediate and tail sections are normally held by clamps or welded to their bottom supports, to stop the line swaying in operation. When the conveyor handles material above 200 °C, fit an expansion joint at the inlet, and do not weld the tail and intermediate sections to their supports — they must be free to expand.

6. Scraper Chain Installation: Direction, Clearance and Tension

The scraper chain is the most important component in the machine. It must articulate freely, run in the correct direction and sit at the correct height above the casing floor.

6.1 Inspect the chain before installation

• Check that every joint between links articulates freely by hand.
• If a joint is stiff, dismantle it, remove rust and clean it, or polish it with abrasive paper until it moves freely.
• Never apply grease or oil to the chain. The chain runs in the material stream; lubricant attracts fines and turns into an abrasive paste.

6.2 Install in the correct direction

Confirm the running direction before the first link goes in. The chain must not be installed backwards. With the head wheel rotating clockwise (viewed from the drive side), the lower run has its small end toward the head and its large end toward the tail; the upper run is the opposite, with the small end toward the tail and the large end toward the head.

6.3 Installation method

1. Install the lower run first. Place an electric hoist directly above and behind the head wheel.
2. Run a wire rope from the tail floor to the head floor and connect it to the hoist.
3. At the lower tail end, connect the other end of the rope to the first group of chain — normally about 10 links.
4. Start the hoist and pull the first group into the casing. Connect the next group, pull it in, and repeat until the lower run is complete.
5. Install the upper run the same way, but in the opposite direction. When the rope emerges at the head, the lower run is complete; repeat for the upper run.
6. At the head, connect the upper and lower runs. At the tail, pull the chain tight, cut it to the correct length and connect the ends. A connecting ring made from 5 mm plate is preferable to a light pressed ring.

6.4 Side clearance

For casing widths between these values, the minimum clearance follows the same proportion. Check the clearance with the chain resting on its guide rails, not hanging free.

6.5 Tensioning

After the chain is connected, adjust the take-up to give the correct slack. When adjustment is complete, the unused travel of the take-up must be at least half of its total travel, so there is room to compensate for chain elongation in service.

7. Inlet, Covers and Drive Unit

7.1 Inlet and covers

Tianyi ships the inlet as a separate item; it is cut and welded on site because the exact position depends on the upstream connection. The procedure is:

1. Lay the cover on the casing and hold the inlet against the upstream connection with bolts.
2. Mark the actual opening on the cover with a scribe, remove the inlet and the cover, cut the opening and grind the edges.
3. Refit the cover and fix it down, then weld the inlet to the cover.
4. Bolt the inlet to the upstream connection with a gasket between them; where sealant is specified, apply it to both faces of the gasket.

The centreline of the inlet must be within ±2 mm of the centreline of the mating connection. Every casing cover must have a gasket; a cover without one leaks dust and lets water in.

7.2 Drive unit

• Before mounting the motor, run it unloaded for 2 continuous hours and check the current variation and bearing temperature rise against the motor manual.
• Weld the motor-reducer and the transmission firmly to the foundation platform or to the head section, as specified in the technical agreement and contract.
• The reducer output shaft must be parallel to the head wheel shaft. On an open chain drive, the centres of the large and small sprockets must lie on one straight line.
• After alignment, weld the drive to the foundation or tighten the anchor bolts so the unit runs without vibration.

8. Safety Devices, Water Jacket and Electrical Wiring

• Chain guard. Fit a guard over the transmission chain before the machine is run.
• Chain-break and blockage alarms. Where the contract specifies them, install and fix them at the positions shown on the layout drawing.
• Water-cooled casing. Connect water pipes that match the reserved ports on the casing jacket, and pressure-test the jacket and connections for leaks.
• Electrical wiring. Run the cables from the local control box to each electrical component strictly according to the electrical schematic. Number every cable and record it. Do not guess a connection because the terminal looks similar.
• Final clean. Remove all installation debris, welding slag and water from the casing before commissioning. A forgotten tool or offcut will jam the chain on the first start.

9. No-Load and Load Commissioning

Commissioning is done in two stages, and the first stage is not optional. The machine runs empty first, is adjusted, and only then is loaded — gradually.

9.1 Checks before the first start

• All bearings, transmission chains and the reducer are filled with the specified lubricant.
• The casing is clean and free of tools, material and water.
• The chain slack is roughly correct. Turn the motor-reducer coupling or the motor fan by hand until the lower run is straight, then inspect how the chain leaves the head wheel.
• All covers are fitted and gasketed, and all guards are in place.

9.2 No-load test

At least three people should take part: one at the head, one at the tail and one electrician.

1. Jog the drive. The observer at the head checks the head wheel rotation direction. If it is wrong, the electrician reverses the motor.
2. Jog again. Watch the chain as it leaves the head wheel. If the chain arches or climbs, adjust the tail take-up screws to increase tension until it runs correctly.
3. Jog for longer. The observer at the tail checks for chain mistracking through the tail cover. If the chain runs to one side, adjust the take-up screw on that side.
4. Run continuously empty. Once rotation, tension and tracking are correct, start the continuous no-load run. Keep observers at their posts; stop immediately on any abnormality.

A moderate sliding noise is normal: the chain runs on guide rails by sliding friction, and the noise usually drops noticeably under load. Knocking, scraping or intermittent catching is not normal and must be investigated before loading.

9.3 Load test

• Run the machine empty for 2 hours before loading.
• Feed uniformly and increase the rate gradually. Never dump a full load into the casing at once.
• Check that the material is within the conveyor's design range — particularly maximum particle size and moisture content. If it is not, correct the material before the load test.
• Watch the discharge. If material does not leave smoothly, find and fix the cause before increasing the load.
• Record the baseline data: voltage, current, power and throughput, and compare them with the design figures.
• Run loaded for 8 hours, then stop. Before stopping, stop the feed and let the casing empty completely.
• Close and fix all inspection covers when the test is complete.

10. Operation, Lubrication, Troubleshooting and Wear Parts

10.1 Operating rules

• After every start, run empty for 15 minutes before feeding material.
• Do not stop under load unless it is unavoidable. Normally, empty the casing before stopping.
• On a line made up of several en-masse conveyors, start the last machine first and work backwards; stop in the reverse order.
• During operation, check the chain for damage and check bolts for loosening — especially the bearing housings and support bolts. Repair or replace anything that is loose or damaged.
• Keep iron pieces and large lumps out of the casing. They damage the chain and can jam the machine.
• Keep all bearings and drive parts lubricated, but keep grease out of the casing.

10.2 Lubrication schedule

10.3 Troubleshooting

10.4 Common wear parts

Keep these items in the site store: large and small sprockets; head wheel hub and teeth; support rollers and shafts; chain pin shafts; single-row scraper chain; transmission chain (16A / 24A / 32A); and bearing assemblies.

10.5 Handover acceptance

The installation and trial-run report should record, at minimum: foundation and support integrity; casing straightness; casing symmetry and flange alignment; head and tail wheel alignment; chain direction, clearance and tension; inlet and cover sealing; drive alignment and rotation; safety devices; electrical numbering; lubricant grade and quantity; and the no-load and load-run results. Acceptance limits include a bearing temperature rise of no more than 40 °C after two hours of no-load running, no leakage or blockage under load, and noise below 85 dB at 1 m from the machine.