Feeding Tank Length and Excavator Cycles

The feeding tank is the least glamorous row on any specification sheet and one of the most consequential for daily operation. Its length decides how much material sits staged in front of the blade — and therefore how many excavator cycles a shift consumes, how smoothly the machine cuts, and how much of the crew’s day is spent feeding rather than producing. This article is the tank-length decision at flagship scale, where the cycles add up to real money. The reference machine is the Q91-2000.

What the Tank Actually Does

The tank is the staging bay between your loading equipment and the blade. Material arrives from the excavator or grapple, sits in the tank, and is advanced to the cutting position by the hydraulic pushing system. Three things follow from that arrangement:

Cycle count. A longer tank holds more staged material, so the excavator fills fewer times per shift. Each fill is a cycle of the loading equipment — and at 250 to 300 tons a day, the difference between a short tank and a long one is a meaningful number of cycles.

Cutting rhythm. A tank that empties between excavator fills starves the cycle; a tank that stays charged keeps the PLC presets working at a steady rate. The rhythm is what delivers the published tonnage, and the tank length is where the rhythm is decided.

Footprint. The other direction: a longer tank takes more floor space, and in a tight yard that is the binding constraint. The tank decision is always a trade between cycles and floor space.

How the Length Is Chosen

The choice is made at quotation against three inputs, and it is a decision rather than an option:

• Your excavator’s reach and cycle time. The loading equipment sets how fast the tank can be refilled. A machine with a long cycle between fills needs a longer tank to keep the blade fed; a fast excavator keeps a shorter tank charged.
• Your material’s bulk density. Dense material — heavy plate, HMS — fills the tank’s weight capacity before its volume; light material fills the volume first. The tank length that suits dense flagship feed differs from the one that suits light intake.
• Your footprint. The route the machine travels into the yard and the floor space around it. A longer tank in a tight yard is a constraint discovered at installation rather than at quotation.

The entry class publishes the logic plainly: the Q91-200 offers 4, 4.5 and 5 m tanks — shorter for tight footprints, longer for fewer excavator cycles and smoother continuous cutting. The same logic scales up the range, and the flagship’s tank is specified against the same three inputs at a larger scale.

The Cycles, Counted

The arithmetic that makes the decision concrete is simple and rarely run. Take your daily tonnage, divide by the excavator’s payload per cycle, and you have the fills per shift. Then ask what each fill costs — the excavator’s time, the operator’s attention, and the interruption to the cutting rhythm when the tank runs dry mid-cycle. Multiply by shifts and days, and the tank length that eliminates a third of the fills has a price. At flagship duty that price is large enough to decide the configuration, and it is invisible on any specification sheet.

The same arithmetic runs in reverse for the footprint constraint: floor space has a price too, and in a tight yard the shorter tank wins. The quotation conversation is where the two prices get compared against your site.

The Rhythm the Tank Enables

The deeper point is that the tank is where the cutting rhythm is decided. A machine fed in surges produces in surges — the cycle time stretches when the tank is full and starves when it is empty, and the published band becomes unreachable. A machine fed from a tank that stays charged produces at the preset rate, and the tonnage figure becomes a rhythm rather than a target. At 250 to 300 tons a day the difference between the two is the difference between the flagship’s published band and a machine that never quite reaches it.

This is why the tank length belongs in the duty conversation rather than in the options list. The flagship guide covers the specification conversation at this scale, and the full range publishes the configuration rows per class.

The Tank and the Rhythm

The tank’s deeper job is rhythm, and the rhythm is what delivers the published tonnage. A tank that empties between excavator fills starves the cycle — the machine waits, the crew compensates with surge feeding, and the surge overloads the discharge. A tank that stays charged keeps the presets working at a steady rate, and the tonnage figure becomes achievable rather than theoretical.

At flagship duty the difference is the whole band. The Q91-2000’s 250 to 300 tons per day assumes a tank that stays charged, a discharge that clears at the box’s rate, and a loading arrangement that keeps pace with the cycle. All three are operational, and the tank length is where the first of them is decided.

The Configuration Decision

The tank decision is made at quotation against three inputs — your excavator’s reach and cycle time, your material’s bulk density, and your footprint — and it is a decision rather than an option. The entry class publishes the logic: 4, 4.5 and 5 m tanks, shorter for tight footprints and longer for fewer excavator cycles and smoother cutting. The same logic scales up the range, and the flagship’s tank is specified against the same three inputs at a larger scale.

Send the three inputs with your inquiry and the configuration comes back in writing within two business days, with the crate dimensions your route needs and the floor space your yard needs. The tank is the least glamorous row on the sheet and one of the most consequential for daily operation — the full range publishes the configuration rows per class.

The Tank, Counted

The tank arithmetic is the most under-run computation in the whole specification, and it takes five minutes. Daily tonnage divided by the excavator’s payload per cycle gives the fills per shift. Each fill costs the excavator’s time, the operator’s attention, and a rhythm interruption when the tank runs dry mid-cycle. Multiply by shifts and days, and the tank length that eliminates a third of the fills has a price — and at flagship duty that price is large enough to decide the configuration.

The arithmetic runs in reverse for the footprint constraint: floor space has a price too, and in a tight yard the shorter tank wins. The quotation conversation is where the two prices get compared against your site — the box guide covers the measurement, and the full range publishes the configuration rows per class.

The Tank as a Rhythm Decision

The tank length is a rhythm decision, and the rhythm is what delivers the published tonnage. A tank that stays charged keeps the presets working at a steady rate; a tank that empties between fills starves the cycle and pushes the crew into surge feeding. The dimension is the least glamorous row on the sheet and one of the most consequential for daily operation.

Run the five-minute arithmetic before the quotation conversation, and bring the number. The full range publishes the configuration rows per class, and the tank that comes back is specified against your excavator, your material and your footprint.

Buyer FAQ

What does the feeding tank length decide?

How much material sits staged in front of the blade — and therefore excavator cycles per shift, cutting rhythm, and how much of the day is spent feeding rather than producing.

Is a longer tank always better?

No — it takes floor space, and in a tight yard that is the binding constraint. The choice trades cycles against footprint, and the quotation conversation compares the two prices against your site.

How do I know which length suits my operation?

Three inputs: your excavator’s reach and cycle time, your material’s bulk density, and your footprint. Send them with the inquiry and the configuration comes back in writing.

Does tank length affect throughput?

Through rhythm rather than capacity. A tank that stays charged keeps the presets working at a steady rate; a tank that empties between fills starves the cycle, and the published band becomes unreachable.

What tank options are published?

The entry class publishes 4, 4.5 and 5 m — shorter for tight footprints, longer for fewer excavator cycles and smoother continuous cutting. The same logic scales up the range, specified at quotation against your site. Run the five-minute arithmetic before the quotation conversation, and bring the number — the tank length that eliminates a third of the fills has a price, and at flagship duty that price is large enough to decide the configuration. Run the five-minute arithmetic before the quotation conversation and bring the number — the tank that comes back is specified against your excavator, your material and your footprint rather than against a default.