1. Follower Design
The Secrets To FOLLOWER PUMPS
Follower design is an important aspect in the manufacture of a follower pump. It ensures that the pump can move a large amount of liquid without developing a lot of problems. It also helps to ensure that the pump can be used in a wide range of applications, including pumping pasty and viscous liquids.
The first step in designing the follower of a follower pump is to choose a suitable cam profile for it. The cam profile should be designed to give the follower a simple harmonic motion. This means that the follower will move in a straight line and will not be affected by any accelerations or angular changes.
There are several types of cam profiles, and a designer can choose one according to the specific requirements of their pump design. These requirements can include speed, acceleration, radial displacement and position.
A cylindrical cam is the most common type of cam, and has a circular contour cut on the cylinder surface. It also has a spring-loaded follower that translates along the parallel axis of the cylinder.
Another type of cam is a disk (or plate) cam, which has no regular contour to transmit the motion to the follower. This can be helpful when a precise rotary movement is needed.
These types of cams are generally able to rotate in both forward and reverse directions. However, they are not as smooth or easy to control as a cylindrical cam.
The following are some examples of cams:
Flat Follower: In this type, the follower has a flat surface that makes contact with the cam. This type of follower is usually used when a quick motion is required, but it can develop a high amount of friction and wear over time.
Roller Follower: In this type, the follower also has a flat surface to make contact with the cam, but it is able to reduce the amount of friction and wear over time.
There are ปั้มไลค์ of using a cam and follower mechanism in a machine component. It is a very versatile mechanism that can be used in a variety of machines, including soda machines and aircraft applications. It is also able to absorb a large amount of shock that increases the mechanical efficiency of a machine component.
2. Pump Shaft
The pump shaft is the part of the equipment that transmits power and torque from the driver to the impeller(s). It consists of multiple elements including bearings, couplings, shaft seals, and the pump’s casing. The shaft should be designed for maximum reliability, efficiency and safety.
A good quality shaft should have a high degree of straightness, which prevents vibration at higher speeds and allows the shaft to withstand thermal expansion without bending or twisting. This is important to reduce turbulence in the fluid and the potential for damage.
There are six major materials used to make pump shafts: copper, aluminum, stainless steel, cast iron, nickel and steel. These materials have varying hardness, strength and corrosion resistance.
Shafts made from these materials typically fracture due to bending stresses (excessive rotary bending). These failures appear as if the shaft snapped off at one point on the axis, and they are more common with variable speed devices.
Another common mode of shaft failure is fatigue from torsional stress. This happens when the shaft is pushed too far from its centerline. These torsional fractures are usually less frequent than bending fractures and may appear like the shaft is being sucked away from the axis of rotation.
Pump shafts can also fail due to metallurgical issues, such as undetected porosity in the base stock, improper annealing and/or other process treatments. Some also fail because of poor machining, such as tool drag, sharp radii, or incorrect dimensions.
In addition, some shafts may fail because of a lack of design margins to accommodate torque, fatigue or corrosion. Credible pump manufacturers build their machine shafts with a reasonable design margin for normal startup and operational conditions, but some have higher margins for upset conditions or safety reasons.
The majority of pump shaft fractures/failures occur due to fatigue failure (also known as reversed bending fatigue). This occurs when a shaft experiences excessive bending stresses while being rotated.
A good seal should be installed on the shaft, using a new mechanical seal material. This is a crucial step because the seal faces need to be installed correctly. The rotary portion of the seal needs to be inserted into the shaft and the stationary part placed on top. It should then be set back into the axial or radial seal chamber bore to form a tight, effective seal.
3. Seals
Seals are the key to preventing fluid from escaping and are critical for the optimal performance of pumps. They are available in many forms and should be chosen according to the pumping application and specific needs.
The type of seal used will depend on the type of liquid, how it is handled and its environment. Choosing the right sealing solution will ensure that you have reliable, long-lasting equipment and will increase your pumping lifespan.
Mechanical seals are a good choice for applications where leakage is unacceptable, like pumps that handle hazardous materials. They are durable and can withstand more wear and tear than pump packing without leaking.
They come in various designs and can be installed on a wide range of pump types, depending on the design. These include balanced mechanical seals, unbalanced mechanical seals and double seals.
Balanced seals are generally preferred for high pressure and velocities, while unbalanced seals are best suited for lower pressures and low velocities. They are also a good option for pumps that are designed to handle aggressive or highly viscous liquids, such as those in the mining industry.
One disadvantage to these types of seals is that they can cause coking when exposed to hydrocarbon leakage. To minimize this problem, a stream quench is often employed to wash away the coke as it forms.
Another concern is that these types of seals require maintenance staff and can wear out quickly, especially when compared to other options. This will add to the costs of maintaining them.
Despite these challenges, gland packing is an excellent option for some applications due to its low upfront cost and easy installation. It also tolerates misalignment and axial/radial movement better than mechanical seals, which can help reduce the need for repair.
It is important to discuss your pumping application and specific needs with a trusted seal supplier before selecting a sealing solution to ensure that you have the best solution for your unique situation.
The dynamic seal has become an increasingly successful alternative to stuffing box sealing, a method traditionally utilized on pumping systems. This method allows for the elimination of external water for stuffing box flush, which can save considerable amounts of water and money over time. This can be a great benefit in certain mill environments where water availability is limited or where the cost of water is higher.
4. Bearings
In pump design, bearings are critical components that can impact performance and reliability. Understanding their basic functions is essential to choosing the right type for your application.
A common bearing is a ball or other rolling element that facilitates movement between two mating components without the use of friction. They are commonly used for both rotational and linear movements, allowing for smooth and noise-free operation.
They are made from a variety of materials and come in many different shapes. There are sleeve, bushing, cylindrical, flanged and tapered varieties, each with its own specific characteristics.
Sleeve or bushing bearings are often made of plastic and are the simplest type of bearing, although they can also be manufactured from metal, such as steel. These are the most affordable and reliable choices, but can cause rattling and noise at high speeds, so they are typically only chosen for applications where this isn’t an issue.
Roller and spherical bearings are popular choices for applications that require support of significant radial and axial loads. They can also help compensate for shaft misalignment, absorb heavy shocks and withstand high temperatures.
The secret to reducing pump maintenance costs is to keep the bearings clean, dry and greased. Lubrication quality-enhancing components such as noncontact seals help to prevent oil and grease problems and can increase lubricant life.
When it comes to bearings, it is important to understand the ABEC value and radial play that is typically specified for each bearing type. This value is used to determine if the bearing will be able to move in a controlled way, or if the bearing is likely to slip, spin, and deform.
Ideally, ball and other rolling element bearings should be assembled with axial preload via shims, springs, take up nuts or other assembly methods. This will remove the internal looseness between the balls and raceways and ensure that the axial positioning is accurate.
However, a slight amount of internal looseness between the balls and races is normal and will affect the bearing’s ability to support a load. This can be minimized by incorporating a proper number of balls, a proper radial play value, and a suitable axial load capacity.