58B Chemical Pump Mechanical Seal

The 58B Chemical Pump Mechanical Seal looks closely related to the 58U at first glance, and both are positioned for corrosive service. the product specifications, however, gives the 58B/59B family a higher listed pressure limit: 2.5 MPa versus 1.2 MPa for the 58U/59U family. That does not make the 58B universally "better," but it does make pressure a meaningful selection question when a buyer is choosing between two similar model families.

For an industrial buyer, the practical question is therefore not simply "Do I need a chemical-resistant seal?" It is "What chemical, at what temperature and pressure, and which installation dimensions does the equipment require?"

The 58B in One View

58B vs. 58U: The Most Useful Difference Is Pressure

The 58B/59B family carries a higher pressure rating than the 58U/59U family. For selection, use the stated operating limits together with the actual chemical medium and equipment conditions.

A 58B RFQ Should Start with the Medium, Not the Model Code

"Strong corrosive fluids" is a useful category, but it is not a chemical compatibility chart. Before Qixing confirms a 58B configuration, the buyer should identify the actual fluid, its concentration if known, and the normal and maximum temperature. Those details matter because corrosiveness can change with concentration and temperature, and the technical specifications only provides material codes rather than a full compatibility table.

Seat Selection

The combined 58B/59B page lists BP as the standard stationary seat and BO as the alternative. Unlike the 58U/59U page, the 58B/59B drawing does not clearly assign one seat code to each model in text. For that reason, this page keeps the BP/BO information at family level and does not claim that every 58B must use one specific seat.

For replacement work, the existing stationary seat should be photographed and measured whenever possible. That is a more reliable basis for matching than forcing a seat assignment that the technical specifications itself does not explicitly state.

The Extra Dimensions on the 58B/59B Table Matter

Compared with the 58U/59U table, the 58B/59B page includes D2 and L2 in addition to D3, D4, L, L3, d6 and D7. Those extra dimensions are useful during replacement work because two seals with the same shaft diameter can still differ in the surrounding installation envelope.

• Start with shaft diameter d.
• Check D2, D3 and D4 around the radial installation envelope.
• Check L, L2 and L3 for axial space.
• Confirm d6 and D7 at the shaft/seat side.
• Send clear photos if the old model marking is incomplete.

Material Code Options

the product specifications page lists material choices as codes, not full names. Rather than turning those codes into guessed materials, this page keeps them exactly as printed:

• Stationary ring: Q2 / V1 / Q1
• Rotary ring: A / B / Q2 / Q1
• Secondary seal: T
• Spring and metal parts: F / G / M

If a buyer already knows the old material code, that code can be included in the RFQ. If not, the better route is to send the chemical medium and operating conditions so the material selection can be reviewed.

Why Choose Qixing

A size row can confirm that a 58B size exists. It cannot tell a buyer whether that size, material combination and seat arrangement fit a specific corrosive process. Qixing, the mechanical seal brand of Ningbo Yade Fluid Connector Co.,Ltd, manufactures and supplies mechanical seals for industrial buyers and can review those details together before quotation.

For OEM or replacement projects, the starting point can be a drawing, an old seal, dimensional measurements, a model reference or operating data. The goal is to match the actual duty rather than rely on the model number alone.

FAQ

What sizes are available for the 58B Chemical Pump Mechanical Seal?

The shared 58B/59B table covers shaft sizes from 14 mm to 100 mm.

What pressure is listed for the 58B/59B family?

Maximum pressure is 2.5 MPa.

How does that compare with the 58U family?

The supplied 58U/59U page lists pressure up to 1.2 MPa, while the 58B/59B page lists up to 2.5 MPa.

What temperature and speed are listed?

The operating temperature range is -40°C to +250°C and maximum sliding speed is 15 m/s.

What media are listed?

The application line states "Strong corrosive fluids." It does not provide a detailed chemical list.

Which stationary seat does the 58B use?

The combined 58B/59B page lists BP as standard and BO as alternative at series level, but it does not clearly assign one seat code to 58B in text. Confirm the existing seat for replacement work.

Why are D2 and L2 included in the table?

They are part of the dimension table and provide additional radial and axial information that can help replacement matching.

Can I order by shaft size only?

Shaft size is the first check, but corrosive-service selection should also confirm medium, temperature, pressure, dimensions and material requirements.

Can Qixing customize the 58B?

Qixing can support customized matching based on drawings, samples, dimensions and operating conditions. Non-standard requirements should be confirmed case by case.

58B Dimension Table

Dimensions are shown in millimeters. Model names below use the Qixing-facing 58B designation.