Description
Product Overview
The HMSS40 is a custom make-to-order 4-Inch washable stainless steel mist eliminator filter manufactured to your specified height and width dimensions. Engineered for permanent installation in HVAC systems, outside air ducts, side-access housings, and built-up filter banks where standard catalog sizes do not fit, the HMSS40 delivers the same HM Series impingement-type moisture separation performance as catalog HMS products—built to the exact height and width you specify, with the 900°F temperature rating and “frequent and rigorous” washability that distinguish stainless steel construction from the aluminum HMA model. Contact Metal Air Filters with your required height and width to request a quote and lead time.
Constructed with a 24 gauge stainless steel frame, 30 gauge stainless steel face grids on both the air entry and exit sides, and a 15-ply stainless steel screen wire media pack—multiple layers of corrugated and flat screen wire positioned for efficient drainage, placed between two layers of expanded metal—the HMSS40 delivers consistent moisture separation and particulate filtration performance. The nominal 4” depth produces an actual depth of 3-3/4″ per standard HM Series manufacturing convention. Height and width are fabricated to your specified dimensions with ±1/8” tolerance.
Unlike electrostatic or pleated media filters designed primarily for fine particulate capture, the HM Series mist eliminator operates on the impingement principle: water droplets and oil mist cannot follow the tortuous path through the corrugated stainless steel screen wire layers at rated velocity, causing them to collide with the screen wire surfaces where surface tension holds the collected liquid. The captured liquid accumulates and drains by gravity through the 3/8” diameter drain holes along the bottom of the filter frame when installed with the TOP label facing upward. This passive drainage mechanism requires no power, pumps, or active components—gravity moves collected moisture to the drain while the HVAC system operates normally.
The HMSS40 custom mist eliminator is manufactured by American Metal Filter Company (AMFCO) to the same construction standards as catalog HMS products. The 24 gauge stainless steel frame and 30 gauge stainless steel face grids provide elevated temperature resistance and rigorous washability that aluminum-frame alternatives cannot match. Pop-rivet corner construction and mitered joints maintain critical face dimensions within ±1/8” tolerance. Contact Metal Air Filters to place a custom order: provide your required height, width, and any special requirements such as polyurethane gaskets or Filter Coat treatment. Custom filters are built to your exact dimensions and are non-returnable—verify your housing dimensions before ordering.
⚠️ Important: Custom Make-to-Order — Non-Returnable
This filter is manufactured to your exact specified dimensions and cannot be returned or exchanged for any reason, including dimensions entered incorrectly by the customer at time of order. Each HMSS filter is custom-built to the height and width you provide—production begins upon order confirmation and the finished filter cannot be restocked, resized, or returned. Measure your housing opening precisely, verify both height and width before submitting your order, and contact Metal Air Filters before ordering if you have any doubt about your required dimensions. Incorrect dimensions entered at time of order are the customer’s responsibility and do not qualify for return, exchange, or refund.
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Key Benefits of the HMSS40 Custom Stainless Steel Mist Eliminator Filter
- Made to Your Dimensions: Fabricated to the exact height and width you specify—ideal for non-standard housing sizes, retrofit applications, and built-up filter banks where off-the-shelf catalog sizes do not fit. Provide your required dimensions when ordering and receive a precision-built filter with ±1/8” dimensional tolerance.
- 900°F Maximum Operating Temperature: Stainless steel frame and face grids rated for 900°F continuous operation—625 degrees higher than aluminum HMA alternatives—for industrial process ventilation, heated make-up air, and high-temperature exhaust applications requiring custom dimensions
- Frequent and Rigorous Washability: Stainless steel construction withstands aggressive industrial wash cycles that would damage aluminum-frame alternatives, making the HMSS40 the correct specification for industrial applications where custom sizing and rigorous maintenance are both required
- 99%+ Efficient on 3-Micron Water Droplets: Independently tested and verified performance across all HM Series sizes, including custom-dimensioned filters built to the same specifications as catalog HMS products
- Permanent Washable Design: Rinse with warm water to restore full mist elimination and filtration performance—no replacement media required. Eliminates recurring filter replacement costs while maintaining consistent moisture separation performance
- Heavy-Duty 15-Ply Stainless Steel Screen Wire Construction: Same 15-ply stainless steel screen wire media pack as catalog HMS filters, providing the verified tortuous path geometry for efficient impingement-type moisture separation at rated 500 fpm airflow
- Gravity Drainage System: 3/8” diameter drain holes along the bottom of the stainless steel frame collect and divert captured moisture to a drain when the filter is installed upright with the TOP label facing upward
- Made in USA by AMFCO — UL Classified 900: Manufactured by American Metal Filter Company to the same exacting standards as catalog HMS products. Optional polyurethane gaskets for side-access housing applications
Technical Specifications
The HMSS40 custom 4-Inch stainless steel mist eliminator filter is built to customer-specified dimensions using the same HM Series construction and materials as catalog HMS products. All performance specifications conform to the authoritative AMFCO HM Series Tech Sheet. Dimensional specifications for height and width are provided at time of order.
| Specifications: | Details: |
|---|---|
| Model Number | HMSS40 (HM Series — Custom Make-to-Order Stainless Steel Mist Eliminator) |
| Ordered Size (Custom) | Customer-specified H” x Customer-specified W” x 4” D — provide dimensions when ordering |
| Actual Depth | 3-3/4″ (±1/16”) — height and width fabricated to customer spec (±1/8”) |
| Frame Material | 24 gauge stainless steel |
| Frame Construction | Precision-mitered corners secured with pop rivets; 3/8” diameter drain holes along bottom of frame |
| Face Grid Material | 30 gauge stainless steel (both air entry and exit sides) |
| Media | Stainless steel screen wire — 15-ply: multiple layers of corrugated and flat screen wire positioned for efficient drainage |
| Media Pack Placement | Pack placed between two layers of expanded metal |
| Filter Type | Impingement type washable panel filter — custom make-to-order |
| Primary Function | Moisture/mist separation — collects water droplets and oil mist; diverts liquid to drain |
| Secondary Function | Heavy-duty washable particulate filtration |
| Water Droplet Efficiency | 99%+ efficient on water droplet size of 3 microns and larger (independently tested) |
| Water Droplet Efficiency Detail | 2.5–3 micron: 94.9% • 3–4 micron: 99.1% • 4–5 micron: 99.9% |
| Dust Arrestance / Capacity | Not officially rated for this depth — primary function is moisture/mist separation at 500 fpm |
| Rated Airflow | 500 fpm face velocity |
| Recommended Airflow Range | 450–550 fpm |
| Maximum Operating Temperature | 900°F continuous |
| Washability Rating | Frequent and rigorous |
| Recommended Final Resistance | 0.50 inches W.G. before cleaning |
| Cleaning Method | Rinse with moderate-to-heavy stream of warm water; air dry before reinstalling |
| Adhesive Coating Option | Not supplied from factory; may optionally be sprayed with Filter Coat (water-soluble adhesive and detergent) before installation |
| Gasket Option | Available with polyurethane gaskets on vertical sides for side-access housing applications (specify at order) |
| Installation Orientation | TOP label must face upward for moisture separation drainage |
| Drain Hole Placement | 3/8” diameter drain holes along bottom of frame |
| Filter Weight | Varies by ordered dimensions |
| Compliance & Certifications | UL Classified 900 |
| UPC Code | 840373527397 |
| GTIN Code | 00840373527397 |
| Country of Origin | Made in USA |
How to Order Your Custom 4-Inch Stainless Steel Mist Eliminator
The HMSS40 is a make-to-order product. Because height and width are built to your specifications, please contact Metal Air Filters before placing your order to confirm your required dimensions, lead time, and pricing. Having the following information ready will ensure a fast, accurate quote:
- Required Height: The actual height of the filter you need (in inches, to the nearest 1/8”).
- Required Width: The actual width of the filter you need (in inches, to the nearest 1/8”).
- Drain Hole Placement: Specify if drain holes should be on the short or long dimension of the frame. Standard placement is along the bottom (long or short side depending on installed orientation).
- Quantity: The number of filters required. Custom orders may have minimum quantity requirements—confirm with Metal Air Filters.
- Gasket Option: Whether polyurethane gaskets on the vertical frame sides are required for your side-access housing application.
- Application: Brief description of your application (outside air intake, industrial mist, high-temperature exhaust, etc.) to help confirm the right specification.
⚠️ Non-Returnable — Custom Built to Your Dimensions: These filters are manufactured to the exact height and width you specify and cannot be returned or exchanged for any reason, including incorrect dimensions entered by the customer at time of order. Measure your housing opening carefully and verify your dimensions before confirming your order. Contact Metal Air Filters before placing your order if you are unsure of your required size.
Once your order is confirmed and dimensions verified, production and shipping lead time will be quoted. Custom filters are built to your exact specifications and are non-returnable and non-exchangeable—filters manufactured to incorrect dimensions entered by the customer cannot be returned, exchanged, or refunded. Measure your housing opening carefully, double-check every dimension before confirming your order, and contact Metal Air Filters with any questions before ordering. Contact Metal Air Filters by phone or email to place your custom HMSS40 order.
Commercial & Industrial Applications
The HMSS40 custom 4-Inch stainless steel mist eliminator filter is specified for commercial, institutional, and industrial HVAC applications where standard catalog HMS filter sizes do not match the required housing dimensions—particularly applications requiring the 900°F temperature rating and rigorous washability of stainless steel construction that catalog-size aluminum HMA filters cannot provide at the same temperature.
High-Temperature Non-Standard Housing Applications
Industrial process facilities, commercial kitchens, drying systems, and heated make-up air units with non-standard ductwork dimensions frequently require custom filter sizing at temperatures that exceed the 275°F aluminum filter rating. The HMSS40 provides 900°F capability in a custom-dimensioned stainless steel filter built to the exact dimensions your housing requires, ensuring complete face coverage and moisture separation performance without bypass gaps that defeat impingement capture efficiency.
Industrial Retrofit and Non-Standard Housing Applications
Existing industrial facilities often have HVAC and ventilation systems with non-standard filter housing dimensions fabricated during original construction to plant-specific dimensions. The HMSS40 custom stainless steel mist eliminator provides the same HM Series impingement-type moisture separation in a filter built to the exact dimensions required for proper fitment in these non-standard housings, with the rigorous washability and temperature resistance that industrial environments demand from a permanent washable filter installation.
Built-Up Filter Bank Applications
Commercial and industrial built-up filter banks assembled from site-specific ductwork and framing frequently use non-standard filter dimensions calculated from available housing space rather than catalog sizes. The HMSS40 custom stainless steel filter provides the 900°F-rated, rigorously-washable HMS performance in every cell of a custom built-up filter bank, ensuring uniform moisture separation across the entire bank face area without catalog-size substitutions that leave gaps or reduce capture efficiency at filter perimeters.
Maintenance & Cleaning
The HMSS40 custom stainless steel mist eliminator filter requires periodic washing to maintain optimal moisture separation performance. The HMS’s “frequent and rigorous” wash rating allows aggressive cleaning appropriate for industrial applications with heavy particulate or coolant mist loading. Washing procedure is identical to catalog HMS filter maintenance.
Washing Procedure
Remove the HMSS40 from the filter housing, noting the TOP label orientation. Rinse with a moderate-to-heavy stream of warm water from the clean side through to the dirty side until water runs completely clear. The stainless steel frame and face grids tolerate higher-pressure washing than aluminum-frame alternatives. For filters in oil mist or coolant mist applications, a mild detergent solution may be used followed by a thorough fresh-water rinse. Allow the filter to air dry or shake off excess water before reinstalling. If Filter Coat adhesive treatment is used, reapply after each wash cycle.
Washing Frequency Guidelines
Outside air intake applications in dusty environments typically require washing every 1–3 months. Industrial coolant mist applications may require monthly washing. Commercial moisture separation applications typically require washing every 3–6 months. Visual inspection and monitoring drain hole flow are the most reliable washing indicators.
Installation
Installing the HMSS40 custom stainless steel mist eliminator requires one critical orientation step: the filter must be installed with the TOP label facing upward in all moisture separation applications. Verify your housing interior dimensions accommodate the custom filter dimensions you ordered before installation.
Pre-Installation Checklist
- Confirm housing interior dimensions match the custom filter dimensions ordered (within ±1/8” tolerance on height and width)
- Confirm HVAC system operating temperature does not exceed 900°F at the filter location
- Identify the TOP label and confirm housing orientation allows it to face upward
- Locate drain holes along the bottom frame and confirm they drain to an appropriate collection point
- If gasket option was ordered, verify gaskets are properly positioned on vertical frame sides
- Clean housing interior of accumulated dust and debris
Installation Steps
Shut down the HVAC system. Remove any existing filter. Orient the HMSS40 with the TOP label facing upward. Insert the filter into the housing maintaining upright orientation. Press firmly into place ensuring all four frame edges seat properly against housing walls. Secure with the housing retention mechanism. Verify drain holes are unobstructed. Restore power and restart the HVAC system. Record installation date and orientation. During the first operating period, check the drain area for moisture drainage to confirm correct positioning.
Frequently Asked Questions
What dimensions can I specify for the HMSS40?
Height and width can be specified to your exact requirements in 1/8” increments. The nominal depth is fixed at 4” (3-3/4″ actual depth per HM Series convention). Specify drain hole placement (short or long dimension) when ordering. Contact Metal Air Filters with your required dimensions to receive a quote and confirm lead time.
How does the HMSS40 mist eliminator filter work?
The HMSS40 operates on the impingement principle: water droplets and oil mist cannot follow the tortuous path through the 15-ply corrugated stainless steel screen wire layers at rated 500 fpm velocity and collide with wire surfaces. Surface tension holds the captured liquid until it drains by gravity through the 3/8” drain holes along the bottom of the stainless steel frame. Achieves 99%+ efficiency on 3-micron and larger water droplets.
How do I clean the HMSS40?
Rinse with a moderate-to-heavy stream of warm water from the clean side through to the dirty side until water runs completely clear. The HMS stainless steel model is rated for frequent and rigorous washing. Air dry or shake off excess water before reinstalling. Mild detergent may be used for industrial oil or coolant residue.
What is the maximum operating temperature?
The HMSS40 HMS stainless steel model is rated for 900°F continuous operation—significantly higher than the aluminum HMA model (275°F) and the galvanized HMG model (325°F).
What is the lead time for a custom HMSS40 order?
Lead time varies by dimensions and production schedule. Contact Metal Air Filters with your required dimensions and quantity to receive a current lead time quote. Custom orders cannot be returned or exchanged once production has begun.
Why must this filter be installed with the TOP label facing upward?
The 3/8” drain holes are along the bottom of the frame and only function when the filter is upright with TOP facing up. Installing sideways or inverted prevents captured moisture from draining, reducing separation efficiency and potentially causing liquid re-entrainment.
Are polyurethane gaskets available for the HMSS40?
Yes—specify the gasket option and indicate which sides (short or long) require gaskets when placing your order. For special size filters, also specify if drain holes should be on the short or long dimension of the frame.
How often should I wash the HMSS40?
Outside air intakes in dusty environments typically every 1–3 months; commercial moisture separation applications every 3–6 months; industrial coolant mist applications may need monthly washing. Visual inspection and drain hole flow monitoring are the best washing indicators.
Why Choose the HMSS40 Custom Stainless Steel Mist Eliminator?
The HMSS40 custom HMS Series stainless steel mist eliminator solves the problem of non-standard housing sizes in commercial and industrial applications where standard catalog dimensions do not fit—and where the application demands the 900°F temperature rating and rigorous washability that stainless steel construction provides beyond the aluminum HMA model. With 99%+ water droplet capture efficiency, passive gravity drainage, and the same 15-ply stainless steel screen wire media as catalog HMS filters, the HMSS40 delivers catalog-grade performance in a filter built to your exact dimensions.
Built with 24 gauge stainless steel framing, 15-ply corrugated and flat stainless steel screen wire media, and 30 gauge stainless steel face grids, the HMSS40 provides the elevated temperature resistance (900°F), rigorous washability, and structural durability that industrial facilities require from a custom permanent washable mist eliminator. Made in USA by American Metal Filter Company to the same standards as catalog HMS products. Contact Metal Air Filters to order: provide your required height, width, drain hole placement, quantity, and any special requirements.
