Latest Trends In Hydraulic Pumps

 What are Hydraulic Pumps?

    A hydraulic pump is a mechanical device that converts mechanical power into hydraulic energy. It generates flow with enough power to overcome pressure induced by the load.



    When a hydraulic pump operates, it performs two functions. First, its mechanical action creates a vacuum at the pump inlet which allows atmospheric pressure to force liquid from the reservoir into the inlet line to the pump. Second, its mechanical action delivers this liquid to the pump outlet and forces it into the hydraulic system.

    A pump produces liquid movement or flow: it does not generate pressure. It produces the flow necessary for the development of pressure which is a function of resistance to fluid flow in the system. For example, the pressure of the fluid at the pump outlet is zero for a pump not connected to a system (load). Further, for a pump delivering into a system, the pressure will rise only to the level necessary to overcome the resistance of the load.


Classification of Pumps

Pumps are classified into either positive-displacement or non-positive-displacement.

  • Non-positive displacement pump: A non-positive displacement pump’s output flow rate can change in response to the pressure on the outlet. They use Newton’s first law of motion to move fluid against the system resistance. Although they provide smooth and continuous flows - their flow output is reduced as the system resistance is increased.

Examples of non-positive displacement pumps are:

    • Centrifugal pumps
    • Multi-stage pumps
    • Axial (propeller) pumps

  • Positive displacement pump: A positive displacement pump provides a constant flow at fixed speed, regardless of changes in pressure.

    The pump makes the fluid move by trapping a fixed amount and forcing the volume into the discharge pipe. The liquid flows into the pump as the cavity on the suction side opens or expands, whilst the liquid flows into the discharge as the cavity closes or decreases. Through every cycle of operation, the volume is the same.

    Examples of positive displacement pumps are:

    • diaphragm pumps
    • helical rotor or progressive cavity pumps
    • peristaltic hose pumps
    • piston pumps
    • rotary lobe or gear pumps
    Commonly Used Hydraulic Pumps
  • Gear Pumps:
Gear pumps are fixed displacement, also called positive displacement, pumps. This means the same volume of flow is produced with each rotation of the pump’s shaft. Gear pumps are rated in terms of the pump’s maximum pressure rating, cubic inch displacement, and maximum input speed limitation.





                    Generally, gear pumps are used in open center hydraulic systems. Gear pumps trap oil in the areas between the teeth of the pump’s two gears and the body of the pump, transport it around the circumference of the gear cavity and then force it through the outlet port as the gears mesh. Behind the brass alloy thrust plates, or wear plates, a small amount of pressurized oil pushes the plates tightly against the gear ends to improve pump efficiency.

  • Piston Pumps:
        When high operating pressures are required, piston pumps are often used. Piston pumps will traditionally withstand higher pressures than gear pumps with comparable displacements; however, there is a higher initial cost associated with piston pumps as well as a lower resistance to contamination and increased complexity. This complexity falls to the equipment designer and service technician to understand in order to ensure the piston pump is working correctly with its additional moving parts, stricter filtration requirements, and closer tolerances. Piston pumps are often used with truck-mounted cranes but are also found within other applications such as snow and ice control where it may be desirable to vary system flow without varying engine speed. 


    A cylinder block containing pistons that move in and out is housed within a piston pump. It’s the movement of these pistons that draw oil from the supply port and then force it through the outlet. The angle of the swashplate, which the slipper end of the piston rides against, determines the length of the piston’s stroke. While the swash plate remains stationary, the cylinder block, encompassing the pistons, rotates with the pump’s input shaft. The pump displacement is then determined by the total volume of the pump’s cylinders. Fixed and variable displacement designs are both available. 

  •             Fixed Displacement: With a fixed displacement piston pump, the swashplate is nonadjustable. Its proportional output flow to input shaft speed is like that of a gear pump and as a gear pump, the fixed displacement piston pump is used within open center hydraulic systems.
  •             Variable Displacement: Unlike the fixed displacement design, the swashplate is not fixed and its angle can be adjusted by a pressure signal from the directional valve via a compensator.

  • Vane Pumps:

Today, the vane pump is not commonly found on these mobile (truck-mounted) hydraulic systems as gear pumps are more widely accepted and available.




Within a vane pump, as the input shaft rotates it causes oil to be picked up between the vanes of the pump which is then transported to the pump’s outlet side. This is similar to how gear pumps work, but there is one set of vanes – versus a pair of gears – on a rotating cartridge in the pump housing. As the area between the vanes decreases on the outlet side and increases on the inlet side of the pump, oil is drawn in through the supply port and expelled through the outlet as the vane cartridge rotates due to the change in the area.

  • Clutch Pumps:
A clutch pump is a small displacement gear pump equipped with a belt-driven, electromagnetic clutch, much like that found on a car’s air conditioner compressor. It is engaged when the operator turns on a switch inside the truck cab. Clutch pumps are frequently used where a transmission power take-off aperture is not provided or is not easily accessible. Common applications include aerial bucket trucks, wreckers,



and hay spikes. As a general rule clutch pumps cannot be used where pump output flows are in excess of 15 GPM as the engine drive belt is subject to slip under higher loads.
  • Dump Pumps:

             This type of pump is commonly used in dumping applications from dump trailers to tandem axle dump trucks. The dump pump is specifically designed for one application – dump trucks – and is not suitable for other common trailer applications such as live floor and ejector trailers.




            What separates this pump from the traditional gear pump is its built-in pressure relief assembly and an integral three-position, three-way directional control valve. The dump pump is unsuited for continuous-duty applications because of its narrow, internal paths and the subsequent likelihood of excessive heat generation.

  • Refuse Pumps:

DRY VALVE PUMPS:



            Primarily used on refuse equipment, dry valve pumps are large displacement, front crankshaft-driven pumps. The dry valve pump encompasses a plunger-type valve in the pump inlet port. This special plunger-type valve restricts flow in the OFF mode and allows full flow in the ON mode. As a result, the horsepower draw is lowered, which saves fuel when the hydraulic system is not in use.


LIVE PAK PUMPS:




Live Pak pumps are also primarily used on refuse equipment and are engine crankshaft-driven; however, the inlet on a Live Pak pump is not outfitted with a shut-off valve. With a Live Pak pump, the outlet incorporates a flow-limiting valve. This is called a Live Pak valve. The valve acts as an unloading valve in OFF mode and a flow-limiting valve in the ON mode. As a result, the hydraulic system speed is limited to keep within safe operating parameters.


Hydraulic Pump Market Overview

According to the International Association of Oil & Gas Producers (IOGP), the production indicator for oil is 83% and 101% for gas in North America. High production indicators show the self-sufficiency level and a strong base for export of oil and gas in North America, that in turn demand effective extraction and processing of these resources. Hydraulic pump has outpaced other sets of pumping devices in this industry since it amplifies the artificial lift method used for removing oil and gas from a wellbore through sustainable performance. Owing to this, North America contributed a regional share of 27.84% in 2018. Apart from oil fields, hydraulic pumps are widely used in construction, chemical, and automotive industry. As per the International Organization of Motor Vehicle Manufacturers (OICA), globally 95,634,593 motor vehicle units were manufactured in 2018 which simultaneously provide a gauge sheet for the global hydraulic pump market. The global hydraulic pump market generated revenue worth $7.4 billion for the FY 2018, which is evaluated to increase at a notable CAGR of 4.70% through to 2025.


Depending upon movement type, hydraulic pumps either work as positive displacement or variable displacement. The hydraulic pumps have a wide range of applications in industrial machines such as cranes, aircraft, forklifts, and also in theme park rides. Growing industrialization generates a huge demand for hydraulic pump systems which is projected to rise at a CAGR of 6.81% during the forecast period 2019-2025.

Hydraulic Pump Market Growth Drivers

  • Growing demand for automobiles, boosting the construction industry, and increasing crude oil drilling are constantly expanding the hydraulic pump market.
  • High preference for sustainable equipment and rising dependency of water supplying utilities on hydraulic pumps majorly elevate the global market growth.

Hydraulic Pump Market Key Players

The leading players in the hydraulic pump market are Toshiba Machine Co. Ltd., Dynamatic Technologies Ltd., Eaton Corporation Plc, Danfoss Power Solutions, Bailey International, Parker Hannifin Corporation, LLC, Bosch Rexroth Ltd., Linde Hydraulics, Hydac International, Actuant Corporation, and others.

Toshiba Machine Co. Ltd. is a Japanese machine manufacturing company that provide products such as injection molding machine, auxiliary equipment, and various hydraulic systems to automotive, electronics, and medical industries.

Hydraulic Pump Market Trends And Innovations

· Electro-Hydraulics for E-Vehicles:

Poclain Hydraulics has recently launched an innovative electro-hydraulic machine that gains wide application in forklift trucks due to its low noise production and clean air emission. In close collaboration with electric motors, electro-hydraulic motors provide high efficiency along with equal control over acceleration and deceleration thereby enhancing the longevity of battery life.

· Robot Operated Hydraulic Actuator:

Hydraulic actuators work by consuming the energy provided by the hydraulic pump mechanism which essentially enhances control systems to act according to a given situation. Researches at the Tokyo Institute of Technology have developed a hydraulic actuator that will facilitate effective robot mechanisms in adverse conditions and weather.


Guide: Prof. Dr. Komble
Written By:

Group 3 - TY-ME-A-B3

56 - Prajwal Darade

57 - Dhanashri Daware

61 - Atharva Deore

71 - Roshan Dhadiwal

73 - Rushikesh Dhanedhar


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