technical info

Centrifugal pumps are among the most widely used pump types in industrial applications due to their simplicity and efficiency. They rely on centrifugal force to move fluids through a system, making them ideal for transferring liquids in a variety of industries, including manufacturing, water treatment, and food processing. 

But how does a centrifugal pump work, and what are its key components? This guide will break it down step by step.

Centrifugal pumps are often chosen for their ability to handle:

• High flow rates with consistent pressure.
• Continuous operation with minimal maintenance.
• Customizability to fit specific needs, including material choices like stainless steel, cast iron, or bronze for compatibility with different fluids.
• Varying flow rates and pressure conditions.

Centrifugal Pumps are often the most cost effective pump for an application, with both low upfront costs and little to no maintenance required when compared to other types of pumps, especially all positive displacement pumps. 

Key Components of a Centrifugal Pump

Before understanding how a centrifugal pump works, it’s important to familiarize yourself with the main pump components:

Impeller: A rotating component with vanes or blades that accelerates the fluid outward.

Impellers come in three main types: open, semi-open, and enclosed. Open impellers are simple and ideal for fluids containing solids but are less efficient. Enclosed impellers, by contrast, are more efficient and suited for clean liquids. The choice of impeller depends on the specific application requirements.

Casing: A stationary housing that directs the fluid into the pump and collects it after it leaves the impeller. 

Casings can be designed as concentric casings, with a volute or with diffusers, and their geometry is critical for pump efficiency. Special coatings or materials, such as stainless steel, may be used for the casing to resist corrosion or abrasion in demanding environments.

Concentric casings are used in low flow (less than 200 gpm) or high pressure (higher than 75 psig) pumps.  Volutes are most common in larger pumps where flows are high relative to the pressure.  Diffusers are used most often in high head pumps where more than one impeller is needed for very high pressures.

Suction and Discharge Ports: The suction (inlet) port allows fluid to enter, while the discharge (outlet) port directs it out of the pump.

The orientation and size of these ports are determined by the pumps flow rates and the need to connect to the piping systems. Standardized flange connections help ensure the pump integrates seamlessly into existing setups.

Pump Shaft: Connects the impeller to the motor or drive mechanism.

In larger pumps, the shaft’s alignment is crucial to prevent vibration and wear. High-precision bearings are used to support the shaft and ensure smooth operation.

Mechanical Seal or Packing: Prevents leakage around the rotating shaft.

Mechanical seals are preferred in modern pumps because they minimize leakage and reduce maintenance requirements compared to traditional packing systems. Specialized seals, such as double or cartridge seals, are available for handling hazardous or abrasive fluids.  Packing is rarely used in pumps today.

How Does a Centrifugal Pump Work?

The operation of a centrifugal pump can be summarized in three main steps:

1. Fluid Entry (Suction)

Fluid enters the pump through the suction port, a critical stage influenced by pressure dynamics. To draw the fluid into the pump, a low-pressure zone is created at the eye (center) of the impeller. This low-pressure area is typically generated by the impeller’s rapid rotation, which reduces static pressure at the impeller’s eye relative to the atmospheric or system pressure at the suction port.

The pressure differential forces the fluid into the pump. For this to occur efficiently, it is essential to maintain a continuous flow without cavitation, which happens when the suction pressure falls below the fluid’s vapor pressure. Proper suction line design, including adequate pipe diameter and minimal bends, is key to optimizing fluid entry and preventing disruptions.

Be sure to check the pumps required net positive suction head (NPSHr) is satisfied by the available suction pressure (NPSHa).  If there is not enough suction pressure at startup the pump will cavitate, make a lot of noise and eventually destroy the impeller.

2. Acceleration (Impeller Rotation)

Once the fluid enters the pump, it reaches the rotating impeller, which is the primary energy-transferring component. The impeller blades accelerate the fluid radially outward through centrifugal force. This outward movement imparts significant kinetic energy to the fluid, increasing its velocity.

The impeller’s design – including blade curvature, diameter, and rotational speed – directly affects the pump’s performance. For example, the vane angles of the impeller blades will determine whether the pump has relatively high efficiencies and relatively low NPSHr. The impeller’s material must also match the application to resist wear, corrosion, or temperature extremes.

3. Conversion of Energy (Casing)

As the high-velocity fluid exits the impeller, it enters the volute or diffuser within the pump casing. Here, the casing plays a pivotal role in converting the fluid’s kinetic energy into pressure energy (also known as head).

• Volute Design: A spiral-shaped casing gradually increases in cross-sectional area, slowing the fluid velocity while raising its pressure.
• Diffuser Design: A series of stationary vanes surrounding the impeller reduces velocity more systematically, ensuring efficient energy conversion with minimal turbulence.

The result is a pressurized fluid stream that exits the pump through the discharge port. The discharge pressure depends on factors like impeller speed, casing design, and the fluid’s density. This high-pressure fluid is then ready to be transported through the system.

Contact American Stainless Pumps Today

At American Stainless Pumps, we deliver high-performance, close-coupled, customizable centrifugal pumps designed to meet the demands of your industry. So, whether you need a standard solution or a tailored design, our pumps will provide the durability and efficiency your operation requires.

Contact us today to discuss your needs and discover how our commercial stainless steel pumps can optimize your processes.

If you want your manufacturing operation to continue running smoothly, you need to be able to select the right electric motors for your applications. Jet pump motors come in all shapes and sizes, and the wrong motor might not only cost you money, but bring your operation to a halt. Unfortunately, many manufacturing leaders aren't sure exactly how to select electric motors, and they aren't even sure what they need for their organization.

So how exactly are you supposed to select the right jet pump motors for your commercial application?

Top Priorities for AC Electric Jet Pump Motors

There are many types of electric motors available, from a wide range of manufacturers. Before you can choose the “right” fit for your needs, you should nail down your priorities.

Typical priorities for buying jet pump motors include:

• Specialization/application. Are you going to use this pump motor for a [MB3] water pump? Or a commercial dishwasher pump? Or something else entirely? If you use a motor in the wrong application, it could cause devastating results[MB4] . Even in a best-case scenario, it's going to compromise your productivity and temporarily interfere with your ability to keep things running. In a worst-case scenario, you could be a major safety hazard, threatening your entire workforce.
• Reliability/quality. Obviously, you'll also need to think about reliability and quality. Even within the same category, some motors are strictly better than others. They can withstand harsher conditions, they don't need as much maintenance, and they could last for years longer than their counterparts. All other factors being equal, it's important to choose the most reliable, highest quality motor you can afford.
• Price. Speaking of affordability, you'll need to think about prices as well. This is especially true if you're buying multiple jet pump motors for your systems. Choosing the cheapest pump motor on the market usually isn't ideal, since it will force you to compromise on other factors. But at the same time, it's a good idea to compare cost so you can get the best deal on a pump motor for your specific application.

Key Motor Elements to Consider

Centrifugal pumps, fire sprinkler pumps, chiller pumps, and commercial dishwasher pumps are just a few of the types of pumps that could need a motor to function properly. Your application is going to dictate what type of motor you need.

These are some of the most important considerations:

Specific application needs.

One of the first things you'll need to think about is your specific application and its motor needs. For example, do your motor need to be compatible with a Variable Frequency Drive (VFD)? Does your motor need to be able to withstand a certain ambient temperature? Does your motor need to fit into a specific physical envelope? What size do you need and how much horsepower is required to meet your overall system’s needs?

Environment.

Some motor enclosures are more resistant to humid and/or hot environments than others. In general, the more protection against the elements your motor offers, the more expensive it will be. A totally enclosed fan cooled (TEFC) motor or Washdown Duty motor will often prevent your motor from failing prematurely due to water damage, but you’ll need to consider the specific application and how vulnerable your motor is. Consider consulting with one of our experts for more information.

Pump efficiency.

Some motors are more energy efficient than others. Though not always the case, higher efficiency motors can be more expensive, so this is a tradeoff you'll need to consider. In many cases, higher efficiency components end up paying for themselves, but the math depends on your specific application, the duty cycle of the motor, and how long you plan on using them. Consider consulting with one of our experts for more information.

Construction materials.

Jet pump motors can be made from a wide range of materials, each of which has advantages and disadvantages. Some motor materials are more resilient, some are more cost effective, and some are particularly suited to specific applications. Consider your options carefully and choose the best fit for your needs.

Manufacturer.  

Next, consider the manufacturer of the motor. Two motors that are otherwise identical may have very different levels of reliability due to how they were manufactured and quality checked. It's important to work with a manufacturer that you trust, and one with a reputation for quality work. American Stainless Pumps, Inc has decades of experience with several manufacturers, across multiple factories. We can help you select the best motor for your application.

Maintenance requirements.

Research the maintenance requirements of the jet pump motors you're considering. More complex jet pump motors and jet pump motors in more demanding applications are typically going to require more maintenance, which is something that needs to factor into your equations.

Availability.

You may also need to think about availability. If there are supply chain issues or other economic variables that interfere with the availability of jet pump motors, your first choice may not be immediately available. If you have urgent needs, you may be forced to make a compromise.

Cost.

Finally, you'll need to think about cost. This is the last item on the list because you may not have much wiggle room in what type of pump motor you buy. It's important to prioritize application specificity, quality, and type above price. Only then can you start conducting price comparison analyses in pursuit of the best deal.

There are a lot of factors to consider here, some of which may be beyond the scope of your current understanding. That's why it pays to work with a pump motor expert, who can help you evaluate your needs and choose the right pump motor for your manufacturing company.

Are you ready to buy stainless steel jet pump motors for your stainless steel pumps, chiller pumps, or other commercial applications? The best course of action is to talk to an expert who can help you find the perfect fit for your needs. 

If you’re ready to get started or if you’re interested in a free quote, contact us today!

Commercial pumps play an important role in a variety of industrial settings, so it's important to find the right products, made from the best possible materials. In many ways, stainless steel is advantageous over materials like cast iron, but what is it exactly about stainless steel that makes it such a powerful material for commercial pumps?

Advantages of Stainless Steel Pumps Over Plastic

We can start by comparing stainless steel pumps to their plastic counterparts. What are the advantages of stainless steel over plastic in this application?

• Durability. Different pumps and different applications may have different requirements, but most industrialists are always looking for something durable. Stainless steel is one of the most durable materials available, and it's much more durable than plastic. This allows stainless steel pumps to withstand more wear and tear and handle much more intense environments.
• Longevity. Partially as a byproduct of this, stainless steel offers superior longevity. Your stainless steel pumps are going to last much longer than plastic ones. If you're trying to get the most out of your investment, and make sure your pumps last for many years, stainless steel is likely the right option.
• Chemical and corrosion resistance. People popularly choose stainless steel for kitchen appliances in part because of its corrosion and chemical resistance. Plastics come in many varieties, and there are some designer plastics that are capable of resisting specific chemicals, but even these specially engineered plastics pale in comparison to stainless steel. That's because stainless steel naturally resists a wide range of chemicals and corrosive substances naturally, making it far more versatile and in many cases, more robustly resilient.
• Strength and integrity. Engineers love stainless steel because of its strength and structural integrity. You probably understand this intuitively, as plastic is designed to be somewhat flexible and malleable. Comparatively, stainless steel is stronger and more rigid, and it's far less likely to deform or crack when experiencing mechanical stress. This advantage makes stainless steel far superior to plastic in any heavy duty application.
• Temperature tolerances. You likely know that plastic has the potential to melt, or at least deform, under high temperatures. It also has a tendency to become brittle when experiencing extreme low temperatures. Comparatively, stainless steel has much higher temperature tolerance, and it's capable of withstanding both extreme highs and extreme lows without melting, warping, or becoming brittle.
• Environmental resistance. Generally, stainless steel is better than plastic at resisting environmental conditions. For example, plastic can easily be degraded by UV radiation or saltwater, but stainless steel is resilient to these elements.

Advantages of Stainless Steel Pumps Over Cast Iron

As you can imagine, cast iron has some critical advantages over plastic as well. So what makes stainless steel commercial pumps better than cast iron?

• Corrosion resistance. For starters, stainless steel pumps are more corrosion resistant than cast iron. If you're dealing with an application that involves a hostile environment or corrosive fluids, stainless steel is a better option. For example, in open impellers, cast iron has a tendency to bind up after accumulating rust, eventually leading to pump and motor failure.
• Lighter weight. Compared to cast iron, stainless steel is much lighter compared to its strength. Generally, this makes stainless steel a more versatile material for pumps, and it simultaneously makes stainless steel pumps easier to handle and install.
• Durability. Cast iron is a highly durable material, but stainless steel is arguably even more durable. It can take a more intense beating, and it's significantly less prone to cracking and breaking.
• Longevity. Just as in our comparison to plastic, stainless steel has more longevity. Because of its strength, durability, and other qualities, it's likely going to last much longer than a comparable cast iron pump. You'll also have fewer maintenance needs by upgrading to stainless steel.
• Hygiene and cleanliness. Stainless steel is also known for its hygiene and easy cleanability. It's one of the best materials for applications in industries where hygiene is crucial, such as food, beverage, and pharmaceutical industries. Comparatively, cast iron pumps are more susceptible to contaminants due to the porous nature of cast iron – and they're much harder to clean as well.
• Aesthetics and overall quality. Some people prefer stainless steel for pumps simply because of its aesthetic attributes. Stainless steel is smoother and more visually appealing than cast iron, which makes it the best option in any public-facing or high-end installation. Additionally, the sleek, smooth surface of stainless steel can lead to efficiency improvements.

Are There Downsides for Commercial Stainless Steel Pumps?

So are there any downsides for commercial stainless steel pumps?

The short answer is yes. In some contexts, stainless steel pumps are more expensive to purchase compared to pumps made from other materials such as plastic or cast iron. They’re also heavier than plastic pumps, making them unsuitable for some niche applications. Also, stainless steel is corrosion resistant, not corrosion immune; stainless steel pumps can’t stand up to chlorinated water or sea water in the long term. 

Still, stainless steel pumps are highly advantageous in most situations. 

The Bottom Line for Stainless Steel

So what's the bottom line here?

When it comes to commercial pumps, stainless steel is superior to cast iron and plastic in nearly all applications. It offers practically no downsides, and is the best material to choose if you want:

• A lightweight, relatively inexpensive, strong material. Stainless steel is incredibly strong, considering its weight, it's relatively inexpensive, and yet, it's also highly versatile.
• Corrosion, chemical, and environmental resistance. Stainless steel is also resistant to corrosion, various chemicals, and various environmental hazards, including extreme temperatures. If you need your pumps to be tough, stainless steel is the obvious answer.
• A long life. People also choose stainless steel for pumps they need to last. Stainless steel is relatively low maintenance, and it can last for decades with proper care.

Are you looking for commercial pumps? Are you unsure about the “best fit” for your needs? Our engineers can help guide you to find the perfect solution – so reach out for a free consultation today!