I would like to ask about Plan53

The PL53 scheme generally includes two versions: 53A and 53B. These two have different structures and also operate on different principles

Take a look; these are the commonly used flushing schemes. They can be used individually or together, with PLAN11+53/53 being the most frequently used combination. To facilitate downloading by Haiyou, it will not be uploaded as an attachment; simply copy and paste the text if you need it. PLAN 23 is generally self-flushing; the sealing fluid serves as the medium for transportation, and it is often used for single-face seals in a clean fluid environment, with an external heat exchanger being used to cool the sealing fluid. PLAN 52 is generally suitable for double-end face sealing in applications involving the transport of toxic, harmful, or dangerous media. The sealing fluid is often not the medium being transported, but rather some other liquid that does not interfere with that medium; sometimes the medium itself is used as the sealing fluid, but this is rare. PLAN 01: The fluid flows from the pressure side of the pump cover to the inside of the sealing chamber for circulation. It is recommended for use with clean liquids that require insulation, and it is not suitable for vertical pumps. PLAN02: A sealed chamber without a flushing fluid circulation; conical sealing chambers are typically used to prevent particle accumulation and facilitate heat dissipation, and it is not suitable for vertical pumps. PLAN11: It leads from the pump outlet, passes through an orifice plate to reach the seal, and is used to flush the seal. It is recommended for clean liquids with low viscosity and temperatures below 80 ℃; it is not suitable for use behind the end face of vertical pumps to enter the pump chamber. PLAN13: Leads from the sealed chamber, passes through an orifice plate to the pump inlet; it is used when the pressure in the sealed chamber is close to that at the pump outlet and it is difficult for liquid circulation to occur within the chamber, and is typically applied to vertical pumps. PLAN21: It leads from the pump outlet, passes through an orifice plate and a cooler to reach the seal; it has a high heat exchange load, and is not recommended for use in applications where the medium temperature is above 160 °C. It enters the pump chamber after flushing the seal surface. PLAN23: The circulating fluid is drawn out of the sealed chamber through a pumping loop and cooled; this enables local circulation for heat exchange. The heat exchange load is much lower than that of the PLAN21 system, allowing PLAN23 to serve as a replacement for it. It is recommended to use a return valve to the sealing chamber in high-temperature medium applications. PLAN31 is suitable for applications where the mass fraction of solid particles is less than 1.5% and the particle density is twice that of the medium. The fluid is taken from the pump outlet, passes through a hydrocyclone, with the clean fluid flowing out from the top and entering the sealing chamber. The liquid containing particles flows out from the bottom and returns to the pump inlet. PLAN32: External flushing fluid is injected into the sealing chamber to flush the seal; it is suitable for applications with solid particles or contaminants. When selecting a flushing fluid, it should be taken into account that the fluid must not contaminate the medium, and its consumption is relatively high. PLAN41: It originates from the pump outlet, passes through a hydrocyclone; the clean liquid flows out from the upper part, passes through a cooler, and then enters the sealing chamber. This system is suitable for applications where the medium temperature is below 160 °C, the mass fraction of solid particles is less than 1.5%, and the density of the particles is higher than that of the medium. The liquid under conditions with a particle size twice as large flows out from the bottom and returns to the pump inlet. PLAN52: Uses an external fluid reservoir for a pressure-free double-seal series connection. It is typically employed in pressure-free double-seal applications where high reliability of the shaft sealing system is required. Pressure-free dual-seal closure provides a buffer solution. The inner seal, which is maintained by the pumping ring during normal operation, serves as the first seal and functions as an internal seal. The second sealing chamber is filled with fluid from the buffer tank circulation. A fluid whose pressure is lower than that of the liquid in the sealed chamber. An alarm will be triggered if the inner seal or the secondary seal fails. It can also be used in applications where the pressure of the medium to be pumped is high, and single-stage mechanical seals are not sufficient to meet the requirements. By adjusting the pressure of the buffer, the respective pressure differences of the single-stage seals are controlled to meet the pressure resistance requirements of those seals. PLAN53: It uses an external liquid reservoir to provide pressure for a dual-seal configuration in series. This auxiliary system is necessary for the proper operation of such dual-seal mechanisms, and it is typically used to prevent leaks of highly toxic, flammable, explosive, or volatile substances. Sealed or double-sealed, with an isolation fluid provided. During normal operation, pumping is used; the double-sealed elastic compensating element is located in a clean isolating fluid. The circulation is maintained when the medium contains solid particles and there are crystallization issues. When the pressure in the reservoir is higher than that of the liquid in the sealing chamber, a dual-seal arrangement can also meet the required pressure levels, with a difference of 0.05–0.15 MPa. When the medium being pumped is clean, free of solid particles, or does not pose any crystallization issues, a tandem-seal configuration can also be used; however, in some operating conditions with dual-sealing, a small amount of isolation fluid may be introduced into the working medium, so this aspect needs to be taken into consideration during use. PLAN54: Uses a pressurized external system to supply clean liquid, enabling more thorough circulation of the isolation fluid and thus improving the reliability of the sealing process. The condition loop for the PLAN53 system is achieved through an external pressure system or pump. The pressure in the reservoir is 0.05–0.15 MPa higher than the pressure of the sealed medium. PLAN62 uses externally supplied quenching fluid to flush the atmospheric side of the sealing surface, in order to prevent issues such as internal solidification, external crystallization, and freezing. The quenching fluid can be low-pressure steam, nitrogen, or clean water; it is typically used in applications involving low-temperature media, media that require insulation, and liquids prone to leakage and crystallization on the atmospheric side, thereby preventing the occurrence of these problems.

The PLAN53 flushing scheme is designed for double-end mechanical seals, and it is commonly used in conjunction with PLAN02/PLAN11/PLAN21/PLAN23/PLAN32, among others. The specific combination to be used must be determined based on factors such as site conditions and the properties of the medium. Combination of end faces: front and back ； Back to back ； It can be face-to-face or not, depending on specific circumstances such as stress levels. Generally, our company faces many back-to-back applications. In the event of a leak in the main seal or external seal, a level or pressure sensor is connected to the control room to trigger an alarm. Furthermore, if the secondary seal leaks, the secondary sealing fluid will leak out from the mechanical seal. This type of alarm is related to the dual-seal design; generally, it is difficult for existing single-face mechanical seals to provide early warnings.

Isn’t the 53 system just a double-seal system? It consists of two sets of seals: an inner seal and an outer seal