Sealless centrifugal pump standard and its selection
June 30 06:05:23, 2025
Sealless centrifugal pump standards and their selection: (1) Sealless centrifugal pumps should be designed with a radially split casing, and axial split casings are not recommended. This ensures better structural integrity and easier maintenance. For the latest order updates, feel free to contact us—our team is here to assist you. Don’t miss out on the newest buyer information; we can provide it at no cost. If you're interested in this product, reach out now for more details.
(2) For medium and light load sealless centrifugal pumps, the minimum design pressure of the pump casing should be 1.6 MPa (G) or higher at 20°C. For heavy-duty sealless pumps, the minimum design pressure should be the lower value between: ①the allowable pressure corresponding to the flange of ISO 7005-1 PN50 (ASME B16.5, Class 300), based on the casing material, and ② 4 MPa (G) at 38°C.
(3) For medium and light load sealless pumps, the flanges should be able to withstand external forces and torque as per the manufacturer’s standard. However, for heavy-duty models, the flanges must meet the requirements of API Std 685-2000, specifically Article 2.4 from NNT API Std 610-1995.
(4) The radial runout (TIR) of the shaft should not exceed 0.05 mm for medium and light load pumps, and less than or equal to 0.025 mm for heavy-duty models. This ensures smooth operation and reduces wear over time.
(5) Medium and light load sealless pumps require dynamic balancing of impellers and other rotating parts according to ISO 1940, G 6.3. Heavy-duty models must have all major rotor components, including couplings in magnetically driven pumps, dynamically balanced to meet ISO 1940 G Class 2.5 standards.
(6) Vibration speed at the bearing points should not exceed 4.5 mm/s for medium and light load pumps at rated operating conditions. For heavy-duty units, within the preferred operating range, vibration should not go beyond 3.0 mm/s. Outside the preferred range, vibration limits may increase up to 130% of these values.
(7) All non-pressurized components of sealless centrifugal pumps should not be made of cast iron to ensure durability and prevent corrosion.
(8) Dry running should be strictly avoided to prevent damage to sliding bearings and isolation sleeves (or shielding sleeves). Always ensure proper lubrication with the process media.
(9) Due to the use of sliding bearings that rely on the process fluid for lubrication, sealless pumps are best suited for media with a viscosity range of 0.1 to 20 mPa·s. When dealing with low-viscosity fluids, a vertical structure can enhance lubrication performance.
(10) Regular monitoring of current, temperature, outlet pressure, leakage, stability, vibration, and noise levels is essential to ensure safe and efficient operation.
(11) Sealless centrifugal pumps typically have lower efficiency compared to sealed pumps. However, for low and medium power applications, the difference in overall efficiency is minimal when compared to double-seal pumps, as the latter consume more power due to cooling and flushing systems.
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