The hydraulic systems that hydraulic pumps support exist in a range of industries, among them agriculture, automotive manufacturing, defense contracting, excavation, and industrial manufacturing. Within these industries, machines and applications that rely on hydraulic pumps include airplane flaps, elevators, cranes, automotive lifts, shock absorbers, automotive brakes, garage jacks, off-highway equipment, log splitters, offshore equipment, hydraulic motors/hydraulic pump motors, and a wide range of other hydraulic equipment.
Hydraulic pumps are commonly constructed using a variety of materials, each selected for specific reasons to ensure optimal performance and longevity. The primary materials utilized for hydraulic pumps are stainless steel, cast iron, and various types of alloys. Stainless steel is a preferred choice for critical components like pump casings, impellers, and shafts due to its high strength, corrosion resistance, and ability to withstand harsh operating conditions. Cast iron is often employed for the pump housing and other non-critical parts, offering cost-effectiveness, good mechanical properties, and ease of manufacturing. Additionally, alloys such as bronze and brass are used for specific pump components, such as bearings and bushings, owing to their low friction properties and resistance to wear and tear. The selection of these materials is critical to ensure the pump’s durability, reliability, and efficient functioning, even under high-pressure and demanding environments, while minimizing maintenance needs and downtime.
Considerations and Customization
Before designing a pump, manufacturers must answer a few questions.
First, what are the operating specifications of their customer? They must make sure that the pump they design matches customer requirements in terms of capabilities. These capabilities include maximum fluid flow, minimum and maximum operating pressure, horsepower, and operating speeds. Also, based on application specifications, some suppliers may choose to include discharge sensors or another means of monitoring the wellbeing of their hydraulic system.
Next, what is the nature of the space in which the pump will work? Based on the answer to this question, manufacturers will design the pump with a specific weight, rod extension capability, diameter, length, and power source.
Manufacturers must also find out what type of substance does the customer plan on running through the pumps. If the application calls for it, manufacturers can recommend operators add other substances to them in order to decrease the corrosive nature of certain hydraulic fluids. Examples of such fluids include esters, butanol, pump oils, glycols, water, or corrosive inhibitors. These substances differ in operating temperature, flash point, and viscosity, so they must be chosen with care.
Hydraulic pumps are crucial components in hydraulic systems, responsible for converting mechanical power into hydraulic energy to generate fluid flow. The primary features of hydraulic pumps include the reservoir, hydraulic hoses or tubes, hydraulic cylinder or cylinders, hydraulic valves, and pistons and gears.
Reservoir: The reservoir serves as a storage tank for hydraulic fluid, providing a constant supply to the pump. It helps in maintaining a stable fluid level, preventing aeration, and dissipating heat generated during the hydraulic system’s operation.
Hydraulic Hoses or Tubes: These act as conduits, transporting hydraulic fluid from the reservoir to the pump and then distributing it to various components throughout the system. The hoses or tubes must be robust and leak-resistant to withstand high pressures and ensure a continuous flow of fluid.
Hydraulic Cylinder or Cylinders: Hydraulic cylinders are key elements used in various applications to convert hydraulic energy into linear mechanical force. They typically consist of a piston and rod that move inside a cylinder, creating controlled movement and power in the connected machinery.
Hydraulic Valves: Hydraulic valves regulate the flow and pressure of the hydraulic fluid within the system. They allow precise control over the movement of actuators (hydraulic cylinders or motors) by directing the flow to different directions and determining the speed and force of the actuator’s movement.
Pistons and Gears: Hydraulic pumps often use pistons or gears to create fluid flow and pressure. Piston pumps generate flow by reciprocating pistons, while gear pumps work through the meshing of rotating gears. Both designs are chosen based on the specific requirements of the application, considering factors such as flow rate, pressure, and efficiency.
The interaction among these features is essential to achieve efficient hydraulic system operation. The hydraulic pump draws fluid from the reservoir through the intake check/valve, ensuring a constant supply. Then, it pressurizes the fluid and delivers it to the hydraulic cylinders or actuators through the discharge check/outlet valve and hydraulic hoses or tubes. The hydraulic valves control the flow direction and pressure, allowing precise and controlled movement of the cylinders to perform the desired mechanical tasks.
The intake check/valve plays a critical role in preventing backflow, ensuring that the pump only draws fluid from the reservoir during the suction stroke and maintaining a steady flow of fluid into the pump. On the other hand, the discharge check/outlet valve prevents reverse flow when the pump is in its compression stroke, ensuring that the pressurized fluid moves in the desired direction, powering the hydraulic cylinders to perform their intended functions. These check valves help maintain system efficiency, prevent damage to the pump, and enable smooth and controlled operation of hydraulic machinery.
How They Work
Hydraulic pumps operate under the principle of Pascal’s Law, which states the increase in pressure at one point of an enclosed liquid in equilibrium is equally transferred to all other points of said liquid.
To start, the check valve is closed, making it a normally closed (NC) valve. When the check is closed, fluid pressure builds. The piston forces the valves open and closes repeatedly at variable speeds, increasing pressure in the cylinder until it builds up enough to force the fluid through the discharge valve. In this way, the pump delivers sufficient force and energy to the attached equipment or machinery to move the target load.
When the fluid becomes pressurized enough, the piston withdraws long enough to allow the open check valve to create a vacuum that pulls in hydraulic fluid from the reservoir. From the reservoir, the pressurized fluid moves into the cylinder through the inlet. Inside the cylinder, the fluid picks up more force, which it carries over into the hydraulic system, where it is released through the outlet.
All hydraulic pumps can be categorized as either single action or double action.
Single action pumps can propel, pull, and lift unidirectionally only.
Double action pumps can move loads in more than one direction.
In addition, all hydraulic pumps are divided into two main groups: piston pumps and gear pumps.
Piston pumps create positive displacement and build pressure using pistons. Piston pumps may be further divided into radial piston pumps and axial piston pumps.
Radial pumps are mostly used to power relatively small flows and very high-pressure applications. They use pistons arranged around a floating center shaft or ring, which can be moved by a control lever, causing eccentricity and the potential for both inward and outward movement.
Axial pumps, on the other hand, only allow linear motion. Despite this, they are very popular, being easier and less expensive to produce, as well as more compact in design.
Gear pumps, or hydraulic gear pumps, create pressure not with pistons but with the interlocking of gear teeth. When teeth are meshed together, fluid has to travel around the outside of the gears, where pressure builds.
Gear pumps are also divided into two categories: external gear pumps and internal gear pumps.
External gear pumps facilitate flow by enlisting two identical gears that rotate against each other. As liquid flows in, it is trapped by the teeth and forced around them. It sits, stuck in the cavities between the teeth and the casing, until it is so pressurized by the meshing of the gears that it is forced to the outlet port.
Internal gear pumps, on the other hand, use bi-rotational gears. To begin the pressurizing process, gear pumps first pull in liquid via a suction port between the teeth of the exterior gear, called the rotor, and the teeth of the interior gear, called the idler. From here, liquid travels between the teeth, where they are divided within them. The teeth continue to rotate and mesh, both creating locked pockets of liquid and forming a seal between the suction port and the discharge port. Liquid is discharged and power is transported once the pump head is flooded. Internal gears are quite versatile, usable with a wide variety of fluids, not only including fuel oils and solvents, but also thick liquids like chocolate, asphalt, and adhesives.
Various other types of hydraulic pumps include rotary vane pumps, centrifugal pumps, electric hydraulic pumps, hydraulic clutch pumps, hydraulic plunger pumps, hydraulic water pumps, hydraulic ram pumps, portable 12V hydraulic pumps, hydraulic hand pumps, and air hydraulic pumps.
Rotary vane pumps are fairly high efficiency pumps, though they are not considered high pressure pumps. Vane pumps, which are a type of positive-displacement pump, apply constant but adjustable pressure.
Centrifugal pumps use hydrodynamic energy to move fluids. They feature a rotating axis, an impeller, and a casing or diffuser. Most often, operators use them for applications such as petroleum pumping, sewage, petrochemical pumping, and water turbine functioning.
Electric hydraulic pumps are hydraulic pumps powered by an electric motor. Usually, the hydraulic pump and motor work by turning mechanisms like impellers in order to create pressure differentials, which in turn generate fluid movement. Nearly any type of hydraulic pump can be run with electricity. Most often, operators use them with industrial machinery.
Hydraulic clutch pumps help users engage and disengage vehicle clutch systems. They do so by applying the right pressure for coupling or decoupling shafts in the clutch system. Coupled shafts allow drivers to accelerate, while decoupled shafts allow drivers to decelerate or shift gears.
Hydraulic plunger pumps use plunger mechanisms in place of pistons and their hydraulic actuator.
Hydraulic ram pumps are a type of hydraulic pump designed to harness hydropower, or the power of water, to elevate it. Featuring only two moving hydraulic parts, hydraulic ram pumps require only the momentum of water to work. Operators use hydraulic ram pumps to move water in industries like manufacturing, waste management and sewage, engineering, plumbing, and agriculture. While hydraulic ram pumps return only about 10% of the water they receive, they are widely used in developing countries because they do not require fuel or electricity.
Hydraulic water pumps are any hydraulic pumps used to transfer water. Usually, hydraulic water pumps only require a little bit of energy in the beginning, as the movement and weight of water generate a large amount of usable pressure.
Portable 12V hydraulic pumps are a battery-operated hydraulic pump type. Operators can use them in emergency applications.
Hydraulic hand pumps are hydraulic pumps that only work after you manually pressurize their hydraulic fluid contents.
Air hydraulic pumps are hydraulic pumps powered by air compressors. In essence, these energy efficient pumps work by converting air pressure into hydraulic pressure.
Hydraulic pumps face competition from various other types of pumps and power transmission systems in terms of applications. Some of the primary competitors include electric motors, pneumatic systems, and mechanical systems. Electric motors are a common alternative to hydraulic pumps, especially in applications where simplicity and ease of use are paramount. However, hydraulic pumps have certain advantages over electric motors. Hydraulic systems can deliver higher power densities, making them suitable for applications requiring high force and torque, such as heavy machinery, construction equipment, and aerospace systems. Additionally, hydraulic systems offer smooth and precise control, making them ideal for tasks requiring accurate movement and positioning.
Pneumatic systems utilize compressed air to generate power and motion and are often preferred in applications where cleanliness and simplicity are essential, such as in food processing or medical devices. However, hydraulic pumps offer higher power output and greater force capabilities compared to pneumatic systems. Hydraulic systems also excel in applications that demand continuous and sustained force, as they can maintain pressure without the need for constant airflow like pneumatic systems. Moreover, hydraulic systems are more adaptable to high-load and heavy-duty applications, making them a preferred choice in industries like construction, manufacturing, and automotive.
Similarly, traditional mechanical systems, such as gears, levers, and pulleys, can be efficient for certain applications, but they have limitations in terms of flexibility and control. Hydraulic pumps outperform mechanical systems in scenarios that require smooth and variable motion control. The use of hydraulic valves allows for precise and proportional control, enabling hydraulic systems to offer finer adjustments and greater versatility. This makes hydraulic pumps more suitable for tasks that demand precision, such as in material handling, marine applications, and aerospace control systems.
In summary, hydraulic pumps have several advantages over their competitors. They provide higher power density, making them well-suited for heavy-duty applications that require substantial force and torque. Hydraulic systems offer smoother and more precise control, giving them an edge in tasks requiring accurate movement and positioning. Additionally, hydraulic pumps can deliver continuous force without the need for constant airflow or electrical supply, providing more consistent performance in various applications. These advantages make hydraulic pumps the preferred choice in industries where power, precision, and adaptability are crucial for successful operation.
Proper care and maintenance are crucial to ensure the longevity and optimal performance of a hydraulic pump. Regular maintenance practices include monitoring fluid levels, checking for leaks, inspecting hoses and fittings for wear or damage, and changing the hydraulic fluid as recommended by the manufacturer. It’s essential to keep the hydraulic fluid clean and free from contaminants by using quality filters and ensuring the reservoir is adequately sealed to prevent moisture and dirt from entering the system. Additionally, maintaining proper pressure and temperature levels is vital to avoid excessive wear and stress on pump components.
Consequences of improper care for a hydraulic pump can be severe and costly. Neglecting maintenance can lead to fluid contamination, resulting in increased friction and wear on pump components, reducing efficiency and potentially causing premature failure. Leaks in the hydraulic system can lead to fluid loss, decreased performance, and safety hazards. If the hydraulic fluid is not changed regularly, it can deteriorate, losing its lubricating properties and causing damage to internal components. Overheating due to insufficient cooling or incorrect fluid levels can also lead to pump failure and other system malfunctions.
On the other hand, properly caring for a hydraulic pump brings several benefits. Regular maintenance helps identify potential issues early, allowing for timely repairs or component replacements, reducing downtime, and minimizing repair costs. A well-maintained hydraulic pump operates more efficiently, ensuring optimal performance and power output, leading to increased productivity and improved system reliability. Proper care also extends the lifespan of the pump and other system components, reducing the need for frequent replacements and saving on long-term maintenance expenses. Furthermore, a well-maintained hydraulic system is safer, as it reduces the risk of sudden failures or accidents, enhancing workplace safety for operators and personnel.
In conclusion, caring for a hydraulic pump through regular maintenance practices is essential to avoid costly consequences associated with improper care. Neglecting maintenance can lead to increased wear, reduced efficiency, and potential pump failure. On the other hand, properly caring for the hydraulic pump results in extended equipment lifespan, improved performance, increased productivity, and enhanced safety. By adhering to manufacturer recommendations and implementing routine maintenance procedures, operators can ensure their hydraulic pumps perform optimally, maximizing their investment and ensuring a reliable and efficient hydraulic system
Standards play a crucial role in the creation and use of hydraulic pumps, ensuring their safety, performance, and compatibility within various applications. Several organizations and agencies are involved in setting these standards, including the International Organization for Standardization (ISO), the American National Standards Institute (ANSI), the European Committee for Standardization (CEN), and the National Fluid Power Association (NFPA).
These standards are essential for multiple reasons. First, they establish uniform specifications and guidelines for the design, manufacture, and testing of hydraulic pumps, promoting consistency and compatibility across different manufacturers and industries. Standards also ensure that hydraulic pumps adhere to safety regulations, reducing the risk of accidents and potential harm to operators and users. Additionally, these standards help in the evaluation and comparison of hydraulic pump performance, allowing consumers to make informed decisions when selecting the most suitable pump for their specific needs.
Using a hydraulic pump that doesn’t meet the established standards can lead to several consequences. It may compromise the safety of the hydraulic system and its operators, as the pump might not withstand the required pressure or have insufficient safety features. Pumps that don’t meet standards might also be prone to premature failure, resulting in costly downtime and repairs. Moreover, these pumps may not deliver the expected performance, leading to inefficient operations, reduced productivity, and increased energy consumption.
On the other hand, using a hydraulic pump that complies with industry standards offers numerous benefits. Such pumps are more likely to be reliable and durable, as they have undergone rigorous testing to meet quality and performance requirements. Meeting standards ensures that the pump will function optimally under the specified conditions, delivering the required flow rate and pressure consistently. Compliant pumps also facilitate easier integration into hydraulic systems, as they meet common industry specifications. Overall, using a hydraulic pump that meets the established standards leads to enhanced system performance, reduced downtime, improved safety, and cost-effectiveness in the long run.
In conclusion, standards set and used during the creation and use of hydraulic pumps are critical for ensuring safety, performance, and compatibility. Various organizations and agencies are involved in developing these standards to promote uniformity, safety, and reliability in hydraulic systems. Using pumps that meet these standards offers numerous benefits, including enhanced performance, durability, and efficiency. On the other hand, the use of non-compliant pumps can result in safety hazards, reduced performance, and costly consequences. Adhering to established standards helps guarantee the optimal performance and reliability of hydraulic pumps, benefiting both manufacturers and end-users alike.
Things to Consider
The highest quality hydraulic pumps come from the highest quality hydraulic pump manufacturers. Finding the highest quality hydraulic pump manufacturers can be hard, which is why we have listed out some of our favorites on this page. All of those whom we have listed come highly recommended with years of experience. Find their information nestled in between these information paragraphs.
Before checking out any of these suppliers, we recommend you take some time to jot down your specifications. That way, you will have an easier time figuring out which ones have potential for you and which ones do not. Plus, when you are ready to talk to a supplier, your list will help you steer the conversation. Do not forget to include in your list the nitty-gritty details like your timeline, your budget and your delivery preferences.
Once you have put together your list, get to browsing. Pick out three or four hydraulic pump supply companies to which you’d like to speak, then reach out to each of them. After you’ve spoken with representatives from each company, decide which one will best serve you, and get started on your project.
Hydraulic Pump Informational Video