Truck-mounted concrete pumps are essential equipment for modern construction, allowing concrete to be efficiently transported to great heights and distances within a worksite. This article provides a detailed step-by-step explanation of how a truck-mounted concrete pump operates, from the hopper to the discharge outlet, including its main components, hydraulic system, articulated boom, and best operating practices for industrial use.

Truck-mounted concrete pumps are essential equipment for modern construction, allowing concrete to be efficiently transported to great heights and distances within a worksite. This article provides a detailed step-by-step explanation of how a truck-mounted concrete pump operates, from the hopper to the discharge outlet, including its main components, hydraulic system, articulated boom, and best operating practices for industrial use.

1. Main Components of the Pumping System

The pumping system of a truck-mounted concrete pump consists of several subsystems that work together to transport concrete in a continuous and controlled manner.

Loading hopper

The receiving hopper is the entry point for concrete. Made of wear-resistant steel, it has a typical capacity of 0.5 to 0.8 m³ and is equipped with a safety grid to prevent oversized materials from entering the pumping circuit. The hopper includes an agitator that keeps the concrete in constant motion, preventing material segregation before pumping.

Pumping cylinders and S-valve

The heart of the system consists of two pumping cylinders: the main cylinder and the material cylinder. The S-valve (transfer valve) is the mechanism that alternates between both cylinders, allowing one to suck material from the hopper while the other pushes concrete toward the discharge pipeline. This twin-cylinder design is the standard in most industrial truck-mounted concrete pumps.

Delivery pipeline and end hose

Concrete travels from the S-valve outlet through high-thickness steel pipe sections until reaching the flexible rubber hose at the end, which allows precise direction of the concrete flow at the placement point. Pipelines typically have diameters of 100 mm to 125 mm and are designed to withstand pressures up to 85 bar.

Technical Specification	Typical Value
Diesel engine power	180 – 300 HP
Maximum pumping pressure	65 – 85 bar
Theoretical pumping capacity	60 – 120 m³/h
Pumping cylinder diameter	200 – 230 mm
Pumping cylinder stroke	1,400 – 1,800 mm
Hopper capacity	0.5 – 0.8 m³
Boom vertical reach	20 – 47 m
Boom horizontal reach	17 – 42 m
Delivery pipeline diameter	100 – 125 mm

 

2. Hydraulic Operating Principle

The hydraulic system generates the force needed to pump concrete through the pipeline. A truck-mounted concrete pump uses a closed hydraulic circuit with high-pressure oil to actuate the pumping cylinders and boom movements.

Main hydraulic pump

The main hydraulic pump is an axial piston variable displacement type, driven directly by the truck's diesel engine through a power take-off (PTO). This pump can deliver flow rates of up to 200 L/min and pressures of up to 350 bar, supplying the hydraulic oil needed for the pumping cycle.

Hydraulic accumulator and relief valve

The hydraulic accumulator stores hydraulic energy to supply peak demand during the S-valve changeover, ensuring a smooth and continuous pumping cycle. The pressure relief valve protects the system against overpressure, and the oil cooler keeps the hydraulic fluid temperature within the optimal operating range of 45 °C to 65 °C.

Hydraulic cooling system

Hydraulic oil heats up during continuous operation. An oil cooler driven by a hydraulic or electric motor keeps the temperature under control, preventing fluid degradation and extending the service life of system components. Excessive oil temperature is one of the most frequent causes of efficiency loss in concrete pump trucks.

3. Step-by-Step Pumping Cycle (From Hopper to Outlet)

The pumping cycle of a truck-mounted concrete pump is a continuous alternating process between two cylinders. Each stage of the cycle is described below.

Step 1: Material loading into the hopper

The mixer truck discharges fresh concrete into the receiving hopper. The hopper agitator keeps the material homogeneous and prevents aggregates from segregating before entering the pumping cylinder.

Step 2: Suction stroke

While one cylinder retracts, the S-valve moves to connect that cylinder with the hopper. The piston withdraws, creating a vacuum that allows concrete to flow into the cylinder. This suction stroke typically lasts between 0.5 and 1.0 seconds.

Step 3: Discharge stroke

Simultaneously, the other cylinder advances, pushing concrete toward the S-valve, which is positioned to connect this cylinder with the discharge pipeline. The piston pushes the material with pressure that can reach 85 bar, forcing the concrete through the pipeline system.

Step 4: S-valve changeover

When the discharge cylinder completes its stroke, the S-valve changes position to connect the cylinder that just finished suction with the discharge pipeline. This switching movement takes less than 0.3 seconds and is precisely synchronized to minimize pulsations in the concrete flow.

Step 5: Alternating cycle repetition

The cycle repeats alternately between both cylinders, generating a nearly continuous flow of concrete. A typical concrete pump truck completes between 20 and 30 cycles per minute, depending on concrete consistency and the selected pumping configuration.

4. Articulated Boom System

The articulated boom is the robotic arm that allows positioning the discharge hose at the exact location where concrete needs to be placed. It is one of the most distinctive components of a concrete boom pump truck.

Boom sections

Articulated booms have between 3 and 5 folding sections, each operated by independent hydraulic cylinders. The sections are made of high-strength steel and fold in a "Z" or "R" configuration for easy transport. The final section includes a flexible rubber hose 3 to 5 meters in length.

Reach and configurations

Booms offer vertical reaches ranging from 20 meters on compact units to 47 meters on large truck-mounted concrete pumps. The maximum horizontal reach may be slightly less than the vertical reach due to boom geometry. Most booms can rotate 360 degrees on the truck base, providing full coverage around the equipment.

Outriggers (hydraulic stabilizers)

Before operating the boom, four hydraulic outriggers are deployed to level and secure the truck to the ground. The outriggers have inclination sensors that lock boom movement if the truck is not properly leveled, preventing tip-overs. The support surface area of each outrigger can reach 0.5 m² to distribute the weight of the loaded equipment.

Professional tip: Before operating a truck-mounted concrete pump, always verify that the outriggers are deployed on firm, level ground. Placing steel plates or thick planks under the hydraulic jacks distributes the load better and prevents sinking in soft soils, especially on worksites with unstable terrain.

5. Remote Control System

The operator controls all boom movements and pumping speed through a wireless remote control, enabling safe and precise operation from near the placement point.

Remote control functions

The remote control allows: starting and stopping pumping, adjusting pumping speed (slow/fast), moving each boom section independently (up/down), rotating the boom left or right, and activating emergency stop. Modern concrete pump trucks include LCD screens on the remote that display pumping pressure, engine RPM, and system alerts.

Safety and emergency stop

All remote controls include a red emergency stop button that immediately halts pumping and locks all boom movements. The system uses radio frequency communication in the 433 MHz or 868 MHz band, with a typical range of 100 to 200 meters on the worksite. If the remote control signal is lost, the system automatically and safely stops all functions.

6. Preparation Before Pumping

Proper preparation is essential to ensure efficient and safe pumping. The operator must follow a verification sequence before starting any operation with a truck-mounted concrete pump.

Component inspection

Check hydraulic oil level, hose condition, accumulator pressure, fuel level, tire pressure, and operation of all warning lights. This pre-operation visual inspection should be completed within 15 minutes following the manufacturer's checklist.

Circuit lubrication

Before the first pump, the inside of the cylinders and pipeline must be lubricated with a cement grout (cement and water mixture) or a specific concrete pump lubricant. This procedure reduces initial friction and prevents concrete from sticking to dry pipeline walls, preventing blockages.

Equipment positioning

The operator must position the concrete pump truck on a level, firm surface, fully deploy all four outriggers, verify leveling using the inclination indicators, and plan the boom trajectory while avoiding obstacles such as overhead power lines, trees, and structures.

7. Operating Procedure

The operating procedure of a truck-mounted concrete pump follows an established sequence to maximize efficiency and safety during pumping.

Start-up sequence

Begin pumping at low speed while verifying that concrete flows correctly through the entire pipeline. Once concrete emerges uniformly from the end hose, gradually increase the speed to reach the desired pumping rate. During the first few minutes, the operator must closely observe flow behavior and system pressure.

Pumping speed adjustment

Pumping speed is regulated according to concrete consistency, pumping distance, and discharge height. For dry or high-strength concrete, a slower speed is recommended to avoid overpressure. For fluid concrete, speed can be increased. Pumping pressure should be kept below 80% of the equipment's maximum pressure to prevent relief valve activation.

Continuous monitoring

During operation, the operator must constantly monitor hydraulic pressure, oil temperature, fuel level, and boom behavior. Any sudden pressure increase may indicate an imminent pipeline blockage, requiring immediate speed reduction or flow reversal to clear the system.

8. Cleaning After Use

Immediate cleaning after pumping is critical to extending the service life of a truck-mounted concrete pump and preventing blockages in future use.

Pressure washing with water

Once pumping is complete, water is pumped through the entire system to remove fresh concrete residue from the pipeline, S-valve, and cylinders. Wash water is discharged at a designated location to prevent soil contamination. This process requires 200 to 500 liters of water, depending on pipeline length.

Cleaning sponges (pigs)

After water washing, one or two sponge balls are introduced into the pipeline, propelled by compressed air or pressurized water to sweep out any remaining residue. This deep-cleaning method ensures the pipeline interior is completely free of hardened concrete.

Post-wash inspection

The operator must visually inspect the hopper, S-valve, and pipeline outlet to confirm no residue remains. Seals and gaskets should be checked and lubricated to prevent dry concrete from damaging sealing surfaces. Finally, the boom is folded and the remote control is stored in its designated place.

9. Preventive Maintenance

Regular preventive maintenance is the key to maximizing the availability and service life of an industrial truck-mounted concrete pump.

Hydraulic oil change

Hydraulic oil must be replaced every 1,000 to 2,000 operating hours, according to manufacturer recommendations and working conditions. Periodic oil analysis detects contamination from metallic particles, water, or thermal degradation before it causes damage to the main pump or system valves.

Component greasing

The lubrication points of the boom, outriggers, S-valve, and pumping cylinders should be greased daily with lithium grease or equivalent. Greasing frequency increases in dusty or high-temperature working conditions, typical in industrial construction projects.

Seal and gasket replacement

Pumping cylinder seals, S-valve gaskets, and hydraulic system seals have a limited service life. They should be inspected every 500 operating hours and replaced at the first sign of wear. A damaged seal in the pumping cylinders reduces volumetric efficiency and can halt production on the jobsite.

Component	Maintenance Frequency	Required Action
Hydraulic oil	Every 1,000 – 2,000 hours	Change and analysis
Hydraulic filters	Every 500 hours	Replacement
Boom and S-valve greasing	Daily	Apply grease
Pumping cylinder seals	Every 500 hours	Inspection
Hydraulic hoses	Every 1,000 hours	Visual inspection
Delivery pipeline	Every 2,000 hours	Pipe rotation

 

10. Frequently Asked Questions

Q1: How much concrete can a truck-mounted concrete pump deliver per hour? The theoretical pumping capacity of a concrete pump truck ranges from 60 to 120 m³/h, depending on the model, concrete consistency, and pumping distance. Under real worksite conditions, practical output is typically 60% to 80% of the theoretical value due to operational stops and material conditions.

Q2: What is the maximum height a concrete pump truck boom can reach? Articulated booms on truck-mounted concrete pumps offer vertical reaches from 20 meters on compact models up to 47 meters on large units. Special models with booms reaching up to 62 meters are available for large-scale projects such as skyscrapers and bridges.

Q3: What type of concrete can be pumped with this equipment? Concrete with slump values between 50 mm and 200 mm can be pumped, using aggregates up to 40 mm maximum diameter. Concrete with slump below 50 mm is difficult to pump due to high internal friction, while very fluid concrete requires lower pressure but may segregate if pumping speed is not properly controlled.

Q4: How are pipeline blockages prevented? Blockages are prevented by maintaining proper aggregate gradation, lubricating the pipeline before pumping, using the correct pumping speed for the concrete type, and performing immediate cleaning after each use. If a blockage occurs, most truck-mounted concrete pumps allow flow reversal to clear the pipeline.

Q5: How long does it take to prepare a concrete pump truck for operation? Complete equipment preparation, including outrigger deployment, leveling, boom extension, and circuit lubrication, takes between 15 and 30 minutes for an experienced operator. Preparation time decreases significantly with practice and when working with a well-coordinated support team.

Q6: What daily maintenance does a truck-mounted concrete pump need? Daily maintenance includes: checking hydraulic oil level, greasing all boom and S-valve lubrication points, visually inspecting hydraulic hoses for leaks or wear, checking tire and outrigger condition, and cleaning the hopper and S-valve after each operation.

Q7: Can concrete be pumped over long horizontal distances? Yes, concrete pump trucks can pump concrete over horizontal distances of up to 400 meters in standard configurations, and up to 1,000 meters with specialized equipment and pipelines. The maximum distance depends on equipment pressure, concrete consistency, pipeline diameter, and the vertical height that must be overcome along the route.

Q8: What is the difference between a boom pump and a stationary pump? A truck-mounted concrete pump with an articulated boom integrates the pumping system, boom, and vehicle into a single self-contained unit, ideal for projects requiring mobility and variable reach. A stationary (trailer-mounted) pump requires a separate crane or boom to position the hose and has lower mobility, but offers higher pumping capacity and pressure for large-volume projects such as tunnels and mining.

Q9: What is the average service life of a truck-mounted concrete pump? With proper preventive maintenance, a truck-mounted concrete pump can last between 8 and 12 years, equivalent to 8,000 – 12,000 operating hours. The factors that most influence service life are maintenance quality, operating conditions, pumped concrete quality, and equipment usage frequency.

11. Summary

A truck-mounted concrete pump is a highly engineered piece of equipment that combines a twin-cylinder pumping system, a high-pressure hydraulic circuit, and a remotely controlled articulated boom to efficiently transport concrete in industrial construction projects. Understanding its step-by-step operation, from hopper to outlet, enables operators and project managers to maximize equipment performance and prevent operational failures.

The alternating pumping cycle, regular preventive maintenance, and immediate cleaning after each use are the three keys to ensuring the productivity and longevity of these machines. Investing in operator training and scheduled maintenance significantly reduces operating costs and unplanned worksite downtime.

At Iron Giant we work with 15+ years of experience in Changsha, offering new and semi-new truck-mounted concrete pumps with after-sales technical support throughout Latin America. We have in-depth knowledge of how these machines operate and the best practices for operation and maintenance to maximize their performance in industrial projects.

Commercial Department, Iron Giant Machinery

Contact Iron Giant today: WhatsApp: +86 19572932608 | Email: manager@hunan-iron-giant.com | Web: www.hunan-iron-giant.com