Why Machine Capacity Matters More Than Filling Speed in OTR Tire Foam Filling

When considering an OTR Tire Foam Filling Machine, mining companies often ask the question:

“How many tires can this machine fill in a day?”

The more relevant question is:

“How much polyurethane can the system deliver accurately while still producing foam of acceptable quality?”

In an operating mine, the filling machine’s capacity is determined not just by the size of the pump, but also by:

• Polyurethane output rate
• Metering precision
• Volumetric size of a tire’s cavity
• Ambient environmental temperature
• Foam formulation
• Gassing out of the foam
• Stability of continuous operation

Many failures with tire filling occur because the operator cares principally about speed of filling rather than about the proper control of the reaction within the tire’s cavity.

For large tires on mining vehicles filling speed is less important to tire performance than the consistency of foam quality throughout the tire cavity.

Understanding Capacity in OTR Tire Foam Filling Equipment

As for other types of tire filling equipment, machine manufacturers normally specify capacity in one of three ways:

Polyurethane Output Rate

Specified in:

Kg/min

Examples of equipment output rated capacity

This parameter indicates how rapidly material is being delivered into the tires. But the output rate by itself does not actually constitute production capacity.

Daily tire processing capacity

Measured in:

Tires per shift

Typical examples:

A machine which can fill 10 medium tires daily will only fill 1 ultra large mining tire in that same period.

3. Annual polyurethane consumption capacity

Some of the larger mining service companies are judging systems against volume each year. For example

• 500 tons/year
• 1,000 tons/year
• 3,000 tons/year
• 5,000 tons per year and higher

This is frequently a more meaningful figure, than number of tires processed per day because of variability in size of miningproblems.

Capacity requirements by application

Underground mining

Typical size of tire to be processed

• 5-25
• 5-25
• 5-25

Recommended equipment of output capability of 8 – 15 kg per min, daily capacity of 6 – 12 tires; metering accuracy ±1%.

Projects place premium on any equipment yielding the quality and versatility to do the job, rather than maximum daily output.

Surface mining fleet

30-ton trucks

Typical size of tire to be processed

• 5-25
• 5-25
• 35/65R33

Recommended equipment having an output capability of 15-35 kg per min with the usual controls for high pressure metering and automatic control of the ratio. Fleet operators may process hundreds of tires a year and need as level a production schedule as possible.

Ultra large mining trucks

53/80R63,59/80R63

Recommended equipment with output capability of from 40120 kg min. Hot, constantly fed foaming technique with explosion. proof design for all electronics, with a material feed system of larger volume.

This floor plan taken up with material storage. For these big jobs foam reaction, control becomes more influential than pump size.

A common, but erroneous assumption

“Bigger pumps mean increased productivity.”

First time buyers frequently think this upward trend exists, since the physical price(tag will indicate difference in size), experienced used to be brewmaster operators usually know that this is not necessarily true.

The reason is this simple!

To produce a usable polyurethane foam, there must be a chemical reaction dependent on the proper amount of isocyanate and polyol (curing component).

The problems are:

• Material enters the tyre too rapidly: the internal rise in temperature increases rapidly, gas generation increases, the cell is unevenly formed, the material shrinks, and heat is more difficult to control.

A machine handling material at 30 kg/min. whose heat generation, by the composition of the foam, is well controlled has proved frequently a better quality of foam than a machine without regard to the quality of foam produced, handling half the quantity (60 kg/min. for instance).

The limit is chemistry rather than pump volume.

How the Size of the Tyre Affects the Size of the Machine Required

The volume of material to be resorted to fill a cavity such as that presented to an on the rim (OTR) tyre becomes many times larger as the size of the tyre increases.

Roughly:

• 5-25 on tyre size requires 180–250 kg PU
• 5-25 350–500 kg
• 5-25 600–900 kg
• 5-25 1,000–1,400 kg
• 35/65R33 1,800–3,000 kg
• 59/80R63 8,000–12,000 kg

The calculation of the volume of the machine to assist the requirements at the service centre are not always realised, and a service centre dealing with two ultra-large mining OTRs may well be filling more PU than another filling twenty small industrial OTRs.

Production Capacity—Criteria

Technical Features That Actually Govern Production Capacity

Metering or Measuring Accuracy

It will be noted that a company is careful with regard to this parameter, as the recommendation runs, “to = 0.5% to = 1.0%”.

Bad ratio control results in:

• “soft foam”
• “hard foam” in terms of density
• foams that “cure out of the mould”
• pre-control heat born of poorly discharged material

Material Temperature

Tempering the material is very much part of the story.

The recommended range is from 22°C to 30°C; if either side of that, viscosity predominates, killing mixing efficiency and stability of density of foam.

Automatic temperature in modern machines seeks to avoid this situation.

The mixing head is central to the pulp of the filling machine.

Key factors in this include:

• Effectiveness of turbulent mixing
• Self-cleaning design
• In-built pressure balancing
• Wear resistance

Poor failings at this point can deprive an effective output of more than 30% of its producing capacity.

Continuous Material Feeding for Large Mining Projects

These types of mining projects will also benefit from:

• bulk material storage tanks
• automatic feeding systems
• continuous circulation loops

This reduces downtime between filling for each tire and are going to have an effect on fill time.

Capacity Planning Formula for Mining Service Providers

A good working method of sizing, if we have all the finance details, is:

1. Quantity of tires in use per year.
2. Average amount of polyurethane used for each tire fill.
3. Total number of kilograms of polyurethane used in one year.
4. Adding to this figure from 15% to 25% to ensure adequate supply.
5. There are various other aspects which we can consider almost dead subservience to supply but if we know the foregoing number of kilograms needed per year it will simply resolve our problem.
6. The chosen machine will be that which gives us output to meet the demand according to its fill time.

Consider, for example, 400 tires per year, possibly even a little more.

The average amount of polyurethane used for each tire fill is 900 kilograms of polyurethane.

Number of kilograms in one year is then:

400 x 900 = 360,000 kilograms of polyurethane for 400 tires per year.

Add 20 % or 72000 kilogs., to give adequate supply.

We arrive at,376,000.

A piece of equipment putting out 20-35 kilograms of fill per minute will therefore adequately supply 400 tires and we do not reach the constitutional point of exhaustion.

• Automatically metered.
• Automatically heated and circulated.

Stability in gear alone adds considerably to spending capital for an investor worth making.

On the opposing side of the arrangement we arrive at a summation leading to good results.

More fateful possibly will be, however, just how much size we exhaust our pocket prolonging with and indeed, just what length is a ticklishly built up dream deck which will die at a moment’s leap.

Again, though, here lies prospective grain.

All fitted to government mast.

Specifications and contracts we fill at the last.

Such spending.

Not moo and the piece all fit together well, well keep looking-that rife and mobile.

2026 Trends in OTR tire foaming filling equipment technologies

A number of noteworthy developments are impacting the OTR tire foaming filling equipment industry.

Smart Ratio Monitoring

New filling systems continuously track changes in:

• polyol flow
• isocyanate flow
• differential pressure
• material temperature

They alert operators to problems in the filling ratio during filling, rather than after an imperfect filling becomes apparent.

Remote Troubleshooting Platforms

Major equipment suppliers around the world are offering increasingly sophisticated:

• engineers access to PLCs
• online diagnostics
• updates
• troubleshooting
• process optimization

A number of issues causing downtime on jobsites can be resolved without dispatching an engineer to the mine.

Automated Foam Density Compensation

Advanced controllers adjust processing automatically when:

• ambient temperature changes
• material viscosity changes
• seasonal conditions change
• material properties vary between different mine sites

Integrated Production Data Systems

Filling stations can now record:

• quantity of foam produced
• tire identifier
• filling quantity
• foam density
• material batch number
• operator record

There are a number of OEMs capitalising on this trend and large mining companies are starting to build into their fleet control systems.

How Do Make Sure You’ve Selected the Right One for Your Operation?

Think carefully about these few priorities when looking at an OTR Tire foam filling machine:

• what your annual polyurethane throughput requirement will be
• tire size distribution
• meter accuracy
• foam reaction stability
• temperature control
• remote troubleshooting features
• expansion plans for fleet growth

The most productive filling machine for most mining applications will not necessarily be the one with the biggest pump.

The best filling system will be the one that allows for accurate ratios of the chemicals, producing consistent foam density and filling quality on every tire brought to it.

Manufacturers like Haifeng Automation and Haifeng PU Technology are moving towards complete turnkey solutions.

Merging their activities for products and PU processors, foams to literally just fit and to assist at any time so to pop.

“all act eternally behind” and innocently get made over into remakes their people, their only true admissions and we outweigh, are going home to fill and arm a few more guns.

At all as mining contractors and tire service people are.

In 2026.

PREGUNTAS FRECUENTES

Q1: What is the optimal output capacity for an OTR Tire Foam Filling Machine?

Answer:

The desirable capacity depends on many factors including the size of tires and the level of production anticipated each year and the size of tires to be filled and the approximate amount of polyurethane consumed for each.

For mining service centres handling the large size of OTR tires, production machines with an output of about 15–35 kg/minute or so provide adequate service.

For operations servicing ultra large mining tires such as 53/80R63 and 59/80R63, 40–120 kg/minute output systems may be required.

Q2: Does a high capacity output always guarantee greater production?

Answer:

No.

Excessive heat build up, faulty cell structure, foam shrinkage, bad curing etc., are all possible as a result of higher output rates.

In fact in many cases a properly controlled 30 kg/minute system will yield better results than a 60 kg/minute larger machine operating without reaction control.

Q3: How much polyurethane does it take to fill an OTR tire?

Answer:

Varies widely by tire size:

etc.

Actual consumption depends on construction of the tire, number of cavities to be filled and density of foam required, etc.

Q4: What type of metering accuracy should an OTR tire filling system exhibit?

Answer:

Plus or minus 1/2 % to 1% metering accuracy represents a desirable minimum for mining applications.

Accurate ratio control charges foams with material of constant density and lessens curing “defects” that reduce the life expectancy of the tire.

Q5: If the temperature of the polyurethane material is not held within specified bounds, what effect will this have?

Answer:

The viscosity of the polyurethane also changes with temperature, causing the material to attack with less efficiency if the material temperature is outside the critical range of 22°C to 30°C.

Result is that unstable foams with incorrect density form, and filling, if completed at all, is poor.

New systems often have functions for automatic heating and “temperature compensation”.

Q6: What features do you feel are the most important in selecting an OTR Tire Foam Filling Machine?

Answer:

• Annual consumption of polyurethane;
• size of tire range;
• metering accuracy superordinate factor effecting size of pump;
• mixing head;
• temperature control;
• automatic feeding of material directly to the mixing head;
• remote troubleshooting;
• production expansion potential;
•  

In fact the above considerations frequently bear a greater relationship to future productivity than does item 1 alone.

Q7: Do you upgrade old tire foam filling equipment instead of replacing complete systems?

Answer:

Certainly many mining service people are opting to upgrade rather than install a completely new system.

Items included in the upgrade are:

• New releasable PLC for control;
• Digital metering;
• Automatic temperature control;
• Remote diagnostics facility;
• High efficiency mixing head;
•  

Q8: What would you consider the most important trends in OTR tire foam filling in 2026?

Answer:

Some of the more encouraging recent trends in this segment of the foam filling service are:

• Smart ratio monitoring systems;
• design for data capture of production records for private fleet management, etc.;
• Automatic foam density compensation;
• remote troubleshooting computer;
• linkage with fleet management computers in touch with various health monitoring systems;

continuous feeding of material to fill head as far as high throughput is concerned.