The double acting Alfa laval pump mechanical seal is a high-performance, flushed cartridge seal designed as a direct replacement and upgrade solution for Alfa Laval LKH and SRU series centrifugal pumps.
Double acting mechanical seal is constructed with industry-standard materials (SiC, Carbon, EPDM, Stainless Steel) suitable for pressures up to 1.0 MPa and temperatures from -20°C to 120°C, making it an essential component for enhancing reliability in challenging food, beverage, and industrial processing environments.
Key Features
• Flushed Seal Design: A replacement for the double-flushed seal arrangement found on Alfa Laval LKH and SRU pumps handling sticky, crystallizing, or high-temperature fluids.
• Barrier Fluid Protection: Alfa laval pump mechanical seals are designed to run with a low-pressure water flush (Plan 52/54) that lubricates the faces and creates a barrier against the process media.
• Prevents Dry Running: The flush ensures the seal faces are always wet, even if the pump runs dry during tank emptying, protecting the seal from heat damage.
• Modular Upgrade: Can replace a single seal in the same pump housing (with addition of flush piping), allowing existing LKH/SRU pumps fitted with standard Alfa Laval pump mechanical seal to be upgraded to handle more difficult fluids.
• Robust Drive: Equipped with strong drive pins/lugs and reinforced elastomer or PTFE bellows to handle viscous drag associated with fluids requiring double acting mechanical seal configuration – suitable for syrup, starch, gelatin transfers.
Applications – Where to Use This Alfa Laval Mechanical Seal / Double Acting Mechanical Seal
Alfa Laval LKH series centrifugal pumps – syrup, chocolate, gelatin, starch transfer (with flush)
Alfa Laval SRU rotary lobe pumps – viscous / crystallizing product lines
Food & Beverage – candy, dairy concentrates, fruit juice concentrate with sugar content
Pharmaceutical – viscous buffer solutions requiring barrier fluid protection
Chemical process – crystallizing media where single seal would foul (requires Plan 52/53A/54 flush)
Applications & Compatible Models
Compatible Pumps:
Alfa Laval® LKH Series (LKH-5 through LKH-90) fitted with double mechanical seal / flushed seal chamber — verify shaft diameter 31.7 mm (1-1/4″) or 42 mm and seal chamber depth.
Alfa Laval® SRU Rotary Lobe Pumps (double-seal configuration).
Also cross-referenced to Vulcan® Type 92D / AES P07U double seal pattern.
Typical Media:
Dairy products (milk, cream, whey), fruit juice/concentrates, beer wort, sugar syrups, honey, gelatin, CIP solutions (NaOH / HNO₃ based), pharma intermediates — clean or mildly viscous, non-abrasive fluids.
Industries: Dairy & Food Processing, Brewing & Beverage, Pharmaceutical & Biotech (non-sterile process), Edible Oil & Fat Handling.
⚠️ Not suitable for: Abrasive slurries, fibrous pulps, media with suspended solids >50 µm, or operation without barrier/flush fluid to the inner seal faces. For high-salinity or aggressive chemical service, consult our engineering team for FKM/PTFE elastomer and SiC/SiC face options.
Technical Specs | Materials | ||
Mediums | Water, oil and weakly-corrosive mediums | Stationary Ring | Ceramic/Sic/TC |
Pressure | ≤1.0MPa | Rotary Ring | Carbon/Sic/TC |
Temperature | -20℃ to 120℃ | Secondary Seal | NBR/EPDM/Viton |
Speed | ≤15m/s | Spring and Metal Part | Stainless Steel |
Product Specifications
| Metric Shaft Size D1 | Size Code | D3 | D7 | L1 | L4 |
| 14 | 0140 | 27.50 | 30.00 | 18.70 | 5.00 |
| 16 | 0160 | 28.50 | 32.00 | 21.00 | 5.00 |
| 18 | 0180 | 31.20 | 35.00 | 22.50 | 7.50 |
| 20 | 0200 | 31.70 | 35.00 | 21.00 | 8.00 |
| 24 | 0240 | 40.20 | 39.00 | 25.50 | 8.00 |
| 25 | 0250 | 40.20 | 40.00 | 25.50 | 8.00 |
| 28 | 0280 | 44.10 | 43.00 | 25.50 | 8.00 |
| 30 | 0300 | 45.10 | 45.00 | 25.50 | 9.00 |
| 32 | 0320 | 49.00 | 48.00 | 33.50 | 9.00 |
| 33 | 0330 | 49.00 | 48.00 | 33.50 | 9.00 |
| 35 | 0350 | 50.20 | 50.00 | 33.50 | 9.00 |
| 38 | 0380 | 55.30 | 56.00 | 33.50 | 9.00 |
| 40 | 0400 | 57.00 | 58.00 | 33.50 | 9.00 |
| 43 | 0430 | 60.70 | 61.00 | 36.50 | 9.50 |
| 45 | 0450 | 62.50 | 63.00 | 38.00 | 9.50 |
| 48 | 0480 | 66.50 | 66.00 | 38.00 | 9.50 |
| 50 | 0500 | 68.60 | 70.00 | 38.00 | 9.50 |
| 53 | 0530 | 70.80 | 73.00 | 41.00 | 9.50 |
| 55 | 0550 | 72.40 | 75.00 | 41.00 | 9.50 |
| 58 | 0580 | 80.00 | 78.00 | 42.00 | 9.50 |
| 60 | 0600 | 83.00 | 80.00 | 42.00 | 9.50 |
| 65 | 0650 | 87.20 | 85.00 | 43.00 | 10.00 |
| 70 | 0700 | 91.60 | 92.00 | 45.00 | 11.00 |
| 75 | 0750 | 99.40 | 97.00 | 48.00 | 12.00 |
| 80 | 0800 | 104.60 | 104.00 | 55.00 | 12.00 |
| 85 | 0850 | 111.00 | 109.00 | 64.20 | 12.00 |
| 90 | 0900 | 113.00 | 114.00 | 66.20 | 12.00 |
Workshop
This workshop is equipped with professional processing equipment and integrated with standardized material warehousing management, enabling a one-stop production process from precision machining to finished product delivery. It ensures part machining accuracy and production efficiency, meeting various high-specification manufacturing requirements.
Product Research, Development and Testing
Our Product R&D and Testing focuses on optimizing seal performance through advanced simulation and material analysis. All seals undergo rigorous trials, including thermal cycling and pressure tests, to ensure durability, minimal leakage, and long service life in demanding industrial environments.
Industry Solutions
Case Study
Syrup Transfer: A beverage plant's single seals were failing due to sugar crystallization on the faces. We upgraded them to this Double acting mechanical seal with a water flush. The water barrier dissolved any sugar crystals, extending seal life from 3 months to over 2 years.
Testimonials
We use these flushed seals on our glucose lines. The water flush keeps everything clean and cool. Essential for our process.
—Process Engineer, Soft Drink Manufacturer
FAQs about Double Acting Alfa Laval Pump Mechanical Seal
Q: Do I need a flush system?
A: Yes, this double seal requires a continuous supply of clean flush water (or compatible barrier fluid). Running it without flush fluid will cause the outboard faces to overheat and fail.
Q: Is this seal a direct replacement for my existing Alfa Laval pump seal?
A: Yes, this seal is designed as a direct, drop-in cartridge replacement specifically for Alfa Laval LKH and SRU series centrifugal pumps. It is built to match the original dimensions and fit, often allowing a modular upgrade from a single seal to a more robust double seal configuration within the same pump housing, though this may require the addition of flush piping.
Q: What is a double acting mechanical seal, and when is it needed?
A: A Double acting mechanical seal (also known as a double or dual seal) features two sets of sealing faces arranged in a back-to-back or face-to-face configuration. It is essential for handling challenging fluids such as syrups, slurries, crystallizing media, or hazardous/volatile liquids. Its primary purpose is to use a barrier fluid (like water) between the seals to prevent the process medium from leaking, to lubricate and cool the faces, and to prevent dry running, especially in pumps handling viscous or abrasive substances.
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