Views: 0 Author: Site Editor Publish Time: 2026-08-27 Origin: Site
A double seal is the right answer for toxic or flammable media. But a lot of pumps never see that. Water treatment, mild chemicals, general transfer. On those, a single cartridge seal is the sensible default, and the ESMH is built to be the one you stock. The trick is not cutting corners on the parts that fail. We kept the faces hydraulically balanced, kept the springs out of the product, and standardized the cartridge so it drops in without a field rebuild. No point saving two dollars on the seal if the downtime costs you two thousand.
Heat is what kills most single seals, full stop. An unbalanced face makes more of it, the elastomer bakes, the leak starts. The ESMH runs hydraulically balanced faces, so it runs cooler and draws less power. The multi-spring layout sits outside the product stream, and that matters more than it sounds. Slurry, crystallizing fluid, anything that settles, it clogs a spring sitting in the flow. Ours does not. The load stays even, the seal lasts. We have watched balanced single seals outlive unbalanced ones by a wide margin on exactly this duty, and the spring placement is most of the reason.
It is a cartridge. Slide it on the shaft, set the clips, done. No stacking faces and springs by hand, no guessing the stack length. Every unit ships with the impeller spacer ring, and the size range is 30, 40, 50, 60, 80 and 90 mm. For a plant keeping a mixed fleet running, that is the difference between a planned swap and a scramble at 2 a.m.
We do not cheap out on the metal, and that is on purpose. Structurally the ESMH is all 316SS. Shaft sleeve, rotary and stationary seats, gland, clamp ring, spring, the screws, the intermediate sleeve. Faces are SSIC or tungsten carbide on both sides. O-rings come in EPR, Viton, Aflas or Kalrez, and there is a PTFE gasket option, so you match the elastomer to what you are pumping instead of changing the fluid to suit the seal. On a plain water or solvent duty we usually leave it at EPR and move on. For mild service that is over-specified in a good way. For the edge of the range it is what keeps the seal alive.
Mostly, the ESMH turns up on chemical and petrochemical lines, oil and gas, water treatment, pharma and food, hazardous handling and marine decks. It is the economical single-seal answer wherever a Sulzer APP or a standard centrifugal pump needs a reliable cartridge without the cost of a double. Built in China by FBU SEALS.
Configuration | Rotary pusher cartridge, single end seal |
|---|---|
Shaft diameter | 30, 40, 50, 60, 80, 90 mm |
Pressure | ≤ 15 bar |
Temperature | -20 °C ~ +120 °C |
Sliding velocity | ≤ 20 m/s |
Seal chamber | Sulzer® APP pump and general centrifugal-pump chambers |
Recommended piping plans | Process side: 01, 02, 03, 11, 12, 13, 14, 21, 22, 31, 32, 41 |
Faces | SSIC / TC (rotary and stationary) |
Structural parts | 316SS throughout; multi-spring set in 316SS, out of media |
O-rings / gasket | EPR / Viton / Aflas / Kalrez; PTFE gasket option |
Q: What is a rotary pusher single mechanical seal and when do you use it?
A: A rotary pusher cartridge seal spins the seal faces and spring assembly with the shaft. The FBU SEALS ESMH is a single end version built for centrifugal pumps like the Sulzer APP. On moderate duty it is the economical choice over a double seal, because one balanced barrier is enough when the fluid is not hazardous. We reach for it whenever the pumped product is benign enough that a single line of defense makes sense.
Q: Which pumps does the FBU SEALS ESMH single seal fit?
A: The ESMH fits the Sulzer APP pump and other standard centrifugal-pump seal chambers. FBU SEALS ships each unit with the impeller spacer ring and covers shaft sizes 30, 40, 50, 60, 80 and 90 mm.
Q: What temperature and pressure can the ESMH centrifugal pump seal handle?
A: FBU SEALS rates the ESMH single seal for up to 15 bar and -20 °C to +120 °C, with sliding velocity up to 20 m/s. For most clean-water and mild-chemical services that is more than enough, which is exactly the duty this seal targets.
Q: What piping plan does the ESMH single seal use?
A: The ESMH uses standard process-side plans 01, 02, 03, 11, 12, 13, 14, 21, 22, 31, 32 and 41. These are the common single-seal arrangements, so in most plants the existing stuffing-box piping already matches and there is nothing to re-engineer.
Q: What are ESMH seal faces and springs made of?
A: ESMH faces are SSIC or tungsten carbide on both the rotary and stationary seats. The wetted structure is all 316SS, including the multi-spring set, and the springs sit outside the product media. O-rings come in EPR, Viton, Aflas or Kalrez with a PTFE gasket option.
