IMI PBM Tank Bottom Valve
Sanitary tank bottom ball valve, IMI PBM Flush Tank range
IMI PBM Valve Solutions – Fully draining tank outlet ball valve, standard and fire-rated versions
The IMI PBM Flush Tank range is designed for tank outlet isolation with full drainage and no dead zone above the ball.
Unlike a 2-way ball valve mounted on a branch, where the section between the tank and the valve creates a systematic dead leg, the tank bottom valve is integrated directly under the tank with a pad radius that matches the geometry of the dished bottom.
The fluid flows with no retention point, the tank drains completely and CIP sweeps the whole assembly without a specific procedure.
Used in pharmaceuticals, biotechnology, food processing, cosmetics and fine chemicals, on mixing tanks, reactors, bioreactors, dissolution tanks and fermenters.
Available configurations
Three main configurations, adapted to the tank geometry and automation constraints:
| Configuration | Series | Typical application |
| Vertical Flush Tank Bottom | Series 5 / 6 | Standard tanks, vertical axial actuation |
| Flush Tank Steam (enhanced thermal resistance) | FD Series 5 | Steam tanks, repeated SIP, heating jacket |
| Angle Stem Tank Bottom (inclined stem) | AF Series 1 | Tanks with low ground clearance, bypassing the bottom or jacket |
The Angle Stem version is specified when the space under the tank is insufficient for a vertical axial actuator or when the heating jacket prevents direct passage.
The inclined stem offsets the actuator away from the tank bottom footprint.
Body and wetted-part materials
Low-ferrite 316L stainless steel as standard.
Alternatives available in AL-6XN® (UNS N08367) for chloride-bearing fluids and in Hastelloy® C-22 or C-276 for extremely corrosive media.
Composition and traceability compliant with ASME BPE. 3.1 material certificate supplied for all wetted parts.
Seats, seals and sealing
Standard V-TEF™ (modified PTFE) seats. FKM and EPDM alternatives available depending on chemical compatibility and temperature.
Encapsulated body gaskets to minimise PTFE cold flow and eliminate cavities where fluid could accumulate.
USP Class VI elastomers, FDA-compliant materials.
Bidirectional bubble-tight sealing upstream and downstream, allowing positive isolation between the tank and the downstream line.
Full vacuum rated as standard, a critical condition for post-SIP cooling phases and vacuum draining.
Adjust-O-Seal® technology
Progressive tightening of the seats against the ball by adjusting the body bolts, in-line, without dismantling or process interruption.
Compensates for normal seat wear and extends the valve’s service life.
Particularly critical on tank bottom valves, whose removal requires the tank to be drained first.
Hygienic design and drainage
Pad radius machined to match the tank bottom geometry and eliminate the pocket above the ball.
No retention zone at the tank outlet, full gravity drainage in the open position.
Body cavity fillers (body fillers) available as an option to minimise zones where fluid could be trapped.
Bottom-entry stem to prevent any risk of accidental blow-out under pressure: the stem can only be removed through the dismantled valve body, not from the actuator.
Surface finish
| Finish | Internal Ra | Target applications |
| Standard mechanical | ≤ 3.20 µm (125 µin) | Food processing, standard cosmetics |
| Fine mechanical | ≤ 0.81 µm (32 µin) | GMP food processing, fine chemicals |
| High-purity mechanical | ≤ 0.51 µm (20 µin) | Pharma, biotech |
| Electropolished | ≤ 0.38 µm (15 µin) | High-purity pharma, WFI, cell culture |
Surface treatments performed without animal-derived ingredients (ADI-free).
Fire-Rated solutions (FT Series 6)
The FT Series 6 version is certified fire-safe according to API-607, which defines a standardised exposure test to a standard flame: the valve, filled and pressurised, is subjected to a flame of about 750 °C for a defined period, then leakage is measured before, during and after exposure, as well as after water cooling.
The API-607 certificate validates that the valve maintains bubble-tight sealing at the body and seats during and after the fire.
Recommended configuration for tanks containing flammable fluids: pharma solvents (ethanol, isopropanol, acetone), monomers, hot oils, process gases.
It is also specified in classified ATEX zones and on processes subject to fire risk assessment.
Specific features of the fire-rated version: secondary metal seats taking over after PTFE destruction in the event of fire, graphite body seals, graphite stem packing, body and ball materials in 316L (ASTM A351 CF3M) or Hastelloy® C-276 to specification.
Compatible with the three-piece swing-out design for routine maintenance.
Sizes available in the fire-rated version: 1/2″ to 4″.
Dimensions and connections
Sizes available from 1″ to 6″ (DN 25 to DN 150), 8″ version on request.
Tank-side connections: machined radius matching the tank bottom for direct welding, or hygienic clamp connection on a short branch.
Outlet-side connection: hygienic clamp (Tri-Clamp), extended tube ends for orbital welding, FNPT thread, ANSI class 150# RF flanges to specification.
Compatible with ASME BPE, DIN 11864 and SMS dimensional standards.
Operating range
Operating pressure up to 62.1 bar (900 psig) depending on series and seat material.
Temperature up to 232 °C with V-TEF™ seats, reduced ranges with FKM or EPDM seals depending on compatibility.
In the fire-rated version, fire resistance certified to API-607 under standardised conditions, with residual leakage compliant with the standard’s requirements.
Actuation
Manual operation by stainless steel handle with non-slip vinyl coating, visual position indicating the open/closed state of the valve.
Reinforced stem/ball engagement for high-torque applications (viscous, crystallised fluids).
Integrated Direct Mount Actuation interface for automation, precise alignment with pneumatic or electric actuators.
Single-acting spring-return actuators (fail-safe close) available for fail-safe processes, particularly in combination with the fire-rated version.
Traceability and packaging
Each valve is supplied with a 3.1 material certificate according to EN 10204 for all wetted parts (CMTR), a USP Class VI declaration of conformity for elastomers, an FDA statement for product-contact materials and an API-607 qualification certificate for the fire-rated version.
Laser marking on the body: reference, size, material, serial number, “Fire Safe API-607” mention where applicable.
Individually packed in a polyethylene sleeve, with capped ends