Jam
The application of sanitary valves in jam production centers on addressing three major challenges associated with transporting and processing high-viscosity media containing fruit pulp particles: preventing clogging, ensuring ease of cleaning, and maintaining corrosion resistance. Spanning the entire production process—from raw material boiling to aseptic filling—these valves are critical equipment for ensuring consistent product texture and food safety.
The following details the specific applications and technical requirements of sanitary valves across various stages of jam production:
1. Key Application Scenarios and Valve Configuration
Jam production primarily involves three stages: vacuum concentration, transfer and filling, and in-line cleaning (CIP). Each stage places specific demands on valve performance.
2. Detailed Technical Requirements
Jam processing imposes specific requirements on valves, focusing primarily on the following aspects:
① Clog-resistant full-bore flow paths
Jam is a typical non-Newtonian fluid characterized by high viscosity and shear-thinning properties, often containing fruit pulp particles. Any constriction or "dead zone" in the valve's flow path can easily lead to clogging; this can range from merely affecting flow rates to resulting in the loss of an entire batch of product. Consequently, full-bore ball valves are the preferred choice for transfer pipelines. Their internal flow diameter matches that of the pipeline exactly, allowing jam to flow smoothly without particles getting trapped at the valve seat. This maximizes the preservation of the jam's original texture and prevents mechanical shearing damage to the fruit pulp.
② Hygienic materials meeting safety standards
All valve components that come into contact with the jam must be made of sanitary-grade materials to ensure food safety.
Valve body material: 304 or 316L stainless steel is mandatory. Among these, 316L (equivalent to German standard 1.4404) offers superior corrosion resistance due to its molybdenum content, making it ideal for withstanding the long-term corrosive effects of citric acid, fruit acids, and salts found in jam processing.
Sealing material: Valve seat seals must be made of food-grade materials. EPDM (Ethylene Propylene Diene Monomer) is the most common choice; it offers heat and chemical resistance, complies with FDA standards, withstands CIP cleaning processes, and serves as the standard sealing material for jam-processing valves. For certain specialized processes, PTFE (polytetrafluoroethylene)—which offers superior heat resistance—is selected.
③ Easy-to-clean surface finish with no dead zones
To prevent microbial growth or cross-contamination between batches caused by jam residue, the internal surfaces of the valve must be exceptionally smooth.
Surface roughness: The roughness (Ra value) of product-contact surfaces is typically required to be ≤0.8 μm—a standard far superior to that of ordinary industrial valves. This mirror-like finish makes it difficult for bacteria and residues to adhere.
Dead-zone-free design: The valve body features a smooth, transitional internal design free of crevices or grooves where product could accumulate. This ensures that jam drains completely during emptying and allows CIP (Clean-in-Place) fluids to thoroughly sanitize every corner.
④ Structural integrity to withstand vacuum and temperature
Vacuum resistance: During vacuum concentration, the tank operates under negative pressure (with a vacuum level reaching up to 96.0 kPa). If the valve seal is compromised, air ingress would disrupt the vacuum, severely impairing concentration efficiency and product flavor. Consequently, the valve must provide a robust seal capable of withstanding the pressure differential against atmospheric pressure.
Temperature adaptability: Jam production involves both heating (with steam temperatures exceeding 150°C) and cooling; the valve must withstand these drastic temperature fluctuations without seal failure.
Summary
In jam production, sanitary valves have evolved beyond simple "on/off" functions to become critical components that safeguard product texture, flavor, and food safety. They must possess core characteristics—such as a full-bore design (to prevent clogging), food-grade materials (for corrosion resistance and safety), and a mirror-polished finish (for easy cleaning)—to reliably ensure food safety at every stage, from raw materials to the finished product.