Primary Mechanical Seal
Overview
The HMT Scissor Shoe Primary Seal is the primary seal of choice for external floating roofs. The original scissor shoe seal was invented by HMT in 1987, and the design has been continuously refined since then. To this day, it remains the most widely utilized and successful primary seal in the industry. The reasons are clear: it works and it’s extremely durable.
For a primary seal that will last, perform well through heavy use, adapt to tank roundness anomalies, span a wide range of rim spaces, and most importantly, maintain tank-shell contact resulting in no gaps, choose the HMT Scissor Shoe.
Key Benefits
The HMT Scissor Shoe Primary Seal relies on innovative design features that contribute key benefits to the end user:
Handles wide range of rim spaces — scissor hanger design performs well in rim spaces ranging from 3.5” to 18” and can be custom-designed to handle rim spaces up to 24”
No gapping — good seal even with wide-ranging rim spaces and tank roundness anomalies
Long life — key components made from custom-hardened stainless steel, ensuring spring longevity and long-lasting seal performance
Low maintenance — workhorse design and materials
In-service install — no hot work required
Key Design Features
Custom-hardened steel will not fatigue
Ten pressure points per shoe create even pressure distribution across the entire shoe
HMT’s scissor shoe stays level as the rim space varies, ensuring a tight fit as roof travels
Premium fabrics for long-life and durability of vapor barrier
Bolt-on design allows for installation and repair while in service
Each HMT seal is designed and sized to fit the specific tank and floating roof dimensions
PTFE fabrics have excellent flame retardant properties; meets DIN 22118 standard
Scissor Shoe Resources
Scissor Shoe Primary Seal Brochure
Product Photo Gallery
Secondary Seal Capacity Chart
Verticality & Roundness Survey Procedures
Chemical Compatibility Chart
Links to Applicable Standards including: API 650,
API 653 & API 2000
Regulatory links including EPA
NFPA – National Fire Protection Association
API - American Petroleum Institute
Tanks 4 - Emissions program
Tanks ESP - Emissions program
