HIGH-PRESSURE PUMPS

When we talk about high-pressure pumps, we mean, first of all, piston pumps capable of pumping large quantities of liquids and fluids within circuits and pipelines.

This is, as already mentioned, the basic operating principle that unites numerous professional tools, differing only in the fluid, flow rate, and pressure to be pumped. Taking the example of the pressure washer: by generating a high-power water jet with a piston pump, the machine for domestic or professional cleaning is activated. But we will see later how numerous and different the fields of application of these pumps are.

First, however, let’s clarify that piston pumps are cataloged as reciprocating positive displacement pumps, consisting of a fixed high-pressure seal chamber and a smooth cylindrical plunger that slides through the seal driven by an endothermic, hydraulic or electric motor.

LEARN MORE: WHAT PISTON PUMPS ARE AND WHAT THEY ARE USED FOR

By reciprocating displacement along an axis, the piston creates the pressure in the cylinder necessary to push the fluid through the entire circuit. This pressure is generated in the chamber by operating valves, both at the suction and delivery points, and reaches values ranging from 10 to 2800 bar.

The sealing chamber, in fact, has an inlet to suck the fluid into the pump and an outlet to actually pump the fluid into the dispensing system: the presence, in these two points, of special valves ensures pressurization and movement of the material to be pumped in one direction only.

When the piston moves away from the inlet, it creates a vacuum, then a suction: the valve opens automatically and the material is sucked into the cylinder chamber. When the piston is pushed in the opposite direction, i.e., toward the outlet, the pressure lifts the closing element of the outlet valve and the fed material is pressurized for dispensing.

READ MORE: MAINTENANCE OF HIGH-PRESSURE PISTON PUMPS

In many ways, piston pumps are very similar to diaphragm pumps but have the main advantage of being designed for very frequent and repeated use and to withstand high pressure.

Depending on the operating pressure they withstand, in fact, we can distinguish between:

• Low-pressure pumps: less than 10,000 psi (69 MPa);
• Medium pressure pumps: 10,000 to 15,000 psi (69 to 103 MPa);
• High-pressure pumps: 15,000 to 40,000 psi (103 to 276 MPa);
• Ultra-high-pressure pumps: Ranging from 40,000 psi to 75,000 psi (276 to 517 MPa).

Starting from this classification, we can deduce that high (and ultra-high) pressure pumps are designed and used to act with the maximum power that can be used, which is why they are used in industrial processes that can be categorized transversally in the removal, even at high impact, of residues of unwanted materials from the most disparate surfaces.

This is done with the application of pumps on high-pressure units: technological equipment characterized by both high effectiveness and high precision in the delivery of the pressurized jet; a factor that exponentially expands the range of professional fields for which pumps are indispensable work tools.

One of the main production processes that high-pressure units carry out is water blasting.

Water blasting is, therefore, a hydro-cleaning procedure  that uses the power of high-pressure pumps to  generate a pressurized jet of water and use it to remove coatings or contaminants from a substrate, objects, buildings, vehicles and surfaces in general. It can be used for cleaning in a wide variety of industrial fields, on different surfaces and for a variety of applications.

It is also called waterjet sandblasting as it is capable of “scraping” unwanted layers of stubborn materials from internal and external surfaces, with the simple force of water and without resorting to sand or other abrasives.

Through the use of high-pressure hoses, lances and special nozzles, for example, water blasting units allow you to remove grease and oil from floors and machinery or to restore rusty metal surfaces.

These systems use pumps at different pressures to perform, respectively:

• High-pressure power cleaning: 11,600 psi (800 bar) to 21,750 psi (1500 bar)
• ultra-high pressure hydro-cleaning: over 1500 bar (21,750 psi)

With the same principle, pressurized water is also used for waterjet cutting on metals, plastics, stone, glass, ceramics and other materials, without the use of blades, saws or flames.

Water blasting also includes hydroscarification, i.e. the selective removal of deteriorated concrete from walls and facades with the sole force of the pressure of the water jet, without transferring any force structurally and avoiding the formation of tension cracks.

The water spouted by the high-pressure pumps, through lances connected to specific nozzles, penetrates the concrete surfaces through the porosity and creates an internal pressure so strong as to cause the detachment of the deteriorated parts, preserving and preserving healthy parts and reinforcements. The pressurized water, in fact, widens the microfractures present in the weakened structure; therefore, the accumulation pressure exceeds the tensile strength of the concrete and causes the already deteriorated concrete to detach.

In a similar way, hydrodemolition greatly speeds up renovation, repair and cleaning operations in the construction field.

READ MORE: HIGH-PRESSURE PUMPS FOR HYDRODEMOLITION

Finally, by adding abrasive materials such as sand or garnet to pressurized water,  abrasive water blasting can be obtained: these particular mixtures increase the removal and cutting capacity, making high-pressure units even more indispensable in various professional and industrial fields.

Finally, by adding abrasive materials such as sand or garnet to pressurized water,  abrasive water blasting can be obtained: these particular mixtures increase the removal and cutting capacity, making high-pressure units even more indispensable in various professional and industrial fields.

The primary advantages offered by this technique are certainly those concerning safety, environmental sustainability, eco-compatibility: by not using chemicals, water blasting does not pose a danger to operators or to the treated surfaces, as well as not dispersing pollutants into the environment through the air or through water collection systems.

The speed and effectiveness of the intervention also allows both labour and time savings in the case of pre-treatment of surfaces for painting operations.

The ease of use and the use of flexible hoses and extensions, on the other hand, allows you to reach and treat even the most inconvenient points for traditional cleaning and sandblasting methods with precision

The fact that it can be used on a wide range of materials and surfaces makes the practice extremely versatile.

The most important advantage, however, is certainly  that it does not damage the surfaces during washing, as no sharp utensils or aggressive substances are used to remove the unwanted layer of dirt and this is applied with extreme precision.

Cleaning units using high-pressure pumps find an infinite range of applications in the most diverse sectors of industry and professional cleaning, below you will find some examples

Removing dust, topsoil, paint, and clogs from:

• Floors
• Vertical surfaces
• Street furniture
• Tanks and containers
• Sewers, drains and drain pipes
• Toilets
• Vehicles
• Heating systems
• Vehicles and machinery

READ MORE: HIGH-PRESSURE PUMPS FOR URBAN CLEANING

Removal of scale and debris of cement, asphalt, garbage, concrete, lime, tar, grease, paint, mastic and clay from:

• Machinery
• Vehicles
• Canals
• Lifts, dams and sliding surfaces

Cutting concrete.

Rehabilitation and sandblasting of tunnels.

Surface hydroscarification of concrete of:

• Large infrastructures
• Dams
• Viaducts
• Homes and offices

Surface preparation.

Roughening of stone and concrete surfaces.

Removal of jammed materials, coats, damaged or corroded coatings from walls and floors.

Removal of scale and sediment of algae, coal, foam, soft polymers and asbestos, wax, paraffin, grease and crude oil residues, limescale scale, calcium sulphate, chlorides, hard polymers, iron oxide, coal, hard coal, PVC and PVA, by:

• Heat exchangers
• Boilers
• Tanks
• Reactors
• Pipping
• Cooling Towers

“Cold” cutting operations.