How to design the seal housing for a double seal pump?

Hey there! As a supplier of double seal pumps, I've been in the thick of designing seal housings for these pumps for quite a while. It's a task that's both challenging and rewarding, and I'm excited to share my insights with you on how to design the seal housing for a double seal pump.

First off, let's understand the basics. A double seal pump is a type of pump that uses two mechanical seals to prevent leakage. The seal housing is the part that holds these seals in place and provides a stable environment for them to operate. It's crucial for the performance and longevity of the pump.

Material Selection

The choice of material for the seal housing is super important. You want something that can withstand the pressure, temperature, and chemical environment of the pumped fluid. For most applications, stainless steel is a great choice. It's corrosion-resistant, strong, and relatively easy to machine. However, if you're dealing with highly corrosive fluids, you might want to consider using materials like Ceramic Mechanical Seal. Ceramics are extremely resistant to corrosion and wear, making them ideal for harsh environments.

Another factor to consider is the thermal expansion of the material. The seal housing needs to maintain its shape and dimensions under different operating temperatures. If the material expands or contracts too much, it can cause misalignment of the seals and lead to leakage. So, make sure to choose a material with a low coefficient of thermal expansion.

Dimensions and Tolerances

Getting the dimensions of the seal housing right is crucial. You need to ensure that the seals fit snugly inside the housing without any gaps or excessive clearance. The inner diameter of the housing should match the outer diameter of the seals within a tight tolerance. A general rule of thumb is to keep the tolerance within ±0.05 mm.

The length of the housing also matters. It should be long enough to accommodate the seals and any additional components like the seal gland. However, it shouldn't be too long, as this can increase the weight and cost of the pump. You also need to consider the space available in the pump for the seal housing.

Cooling and Lubrication

Double seal pumps often require cooling and lubrication to prevent overheating and reduce friction between the seals. The seal housing should be designed with channels or ports for the circulation of coolant or lubricant. These channels should be properly sized and positioned to ensure efficient heat transfer and lubrication.

For example, you can design the housing with a jacket around the seals, through which coolant can flow. This helps to dissipate the heat generated by the friction between the seals and the shaft. You can also include ports for injecting lubricant directly into the seal faces.

Seal Compatibility

Not all seals are created equal, and it's important to choose seals that are compatible with the seal housing and the pumped fluid. Different seals have different materials, designs, and operating characteristics. For example, the Burgmann Mg12 is a popular mechanical seal known for its reliability and performance. It's suitable for a wide range of applications, but you still need to make sure it's compatible with your specific requirements.

You also need to consider the type of double seal arrangement you're using. There are two main types: tandem seals and back-to-back seals. Each type has its own advantages and disadvantages, and the seal housing needs to be designed accordingly.

Assembly and Disassembly

Designing the seal housing with ease of assembly and disassembly in mind is essential. You want to make it as simple as possible for maintenance personnel to replace the seals when needed. This means providing easy access to the seals and using fasteners that are easy to remove and install.

For example, you can use threaded fasteners instead of welded joints. This allows for quick and easy disassembly without the need for special tools or equipment. You can also design the housing with a split design, which makes it easier to access the seals from both sides.

Testing and Validation

Once you've designed the seal housing, it's important to test and validate it before putting it into production. You can use computer-aided design (CAD) software to simulate the performance of the housing under different operating conditions. This can help you identify any potential issues and make necessary adjustments.

You can also perform physical tests on prototypes of the seal housing. This includes pressure testing, leakage testing, and temperature testing. These tests can help you verify the performance and reliability of the housing and ensure that it meets your specifications.

Conclusion

Designing the seal housing for a double seal pump is a complex process that requires careful consideration of many factors. From material selection to testing and validation, every step is crucial for the performance and longevity of the pump. By following the tips and guidelines outlined in this blog, you can design a seal housing that meets your specific requirements and provides reliable operation.

If you're in the market for a double seal pump or need help with the design of a seal housing, don't hesitate to reach out. We're here to assist you with all your pump needs. Whether you have questions about the design process, need advice on material selection, or want to discuss your specific application, our team of experts is ready to help. So, let's start a conversation and see how we can work together to meet your requirements.

References

• "Mechanical Seals: Principles and Applications" by John Adamson
• "Centrifugal Pumps: Design and Application" by Igor J. Karassik