Sanitary Clamp Types From Single Pin Double Pin To High Pressure Clamp Selection

Classification of Sanitary Clamps and Clip Fittings

Classification by Construction

Sanitary clamps can be classified into standard clamps, combined clamps and three-piece clamps according to their structure. The following is an introduction to their composition, characteristics and applications.

Standard Clamp

Description: The most common single-turn clamp, featuring a simple structure consisting of a single metal strip and a hinged joint.

Features: Low cost, light weight, and easy installation.

Applications: Suitable for low-pressure, normal-temperature, and non-critical general connection points.

Union Clamp

Description: Consists of two semicircular ferrules connected by a hinge pin and locking mechanism.

Features: Stronger than standard clamps, provides a more even seal, and can withstand higher pressures.

Application: Widely used in most sanitary pipe connections, it is a popular choice.

Three-Piece Clamp

Description: Consists of two semicircular hoops and a separate “cap” or “clasp.”

Features: Provides optimal pressure distribution and sealing, maximum rigidity, no elastic deformation, and long service life.

Application: Suitable for critical workstations operating under high pressure, high temperature, high vibration, or requiring extreme safety.

Classification By Locking Method

According to the locking method, it can be divided into single pin clamp, double pin clamp and bolt clamp. Let’s talk about them in detail below.

Single Pin Clamp

Description: Locks with a single hinge pin and a manually operated wing nut or lever.

Features: Extremely quick to operate, allowing for one-handed assembly and disassembly.

Applications: Ideal for applications requiring frequent disassembly for cleaning (CIP/SIP), such as reactor inlets and filter connections.

Double Pin Clamp

Description: Features hinge pins at both ends, locked with a central wing nut or lever.

Features: Excellent centering, self-leveling, and more uniform sealing pressure distribution than a single-pin clamp.

Applications: Highly versatile and the preferred choice for most standard applications, balancing ease of operation and sealing reliability.

Bolted Clamp

Description: Latched with one or more bolts and nuts instead of a wing nut.

Features: Provides maximum locking force and the most uniform sealing pressure, with excellent resistance to vibration loosening.

Application: Mainly used in systems with high pressure, high temperature, or strong vibration. It requires tools to install, and the speed is slow.

Classification By Performance And Working Conditions

Heavy-Duty Clamp

Description: Features thicker material, a stronger hinge structure, and a wider collar.

Features: Provides increased mechanical strength and fatigue resistance.

Applications: Suitable for large-diameter pipes, supporting heavy valves, or joints exposed to external stress.

High-Pressure Clamp

Description: Typically a three-piece or reinforced bolt clamp designed to withstand extremely high internal pressures.

Features: Extremely rigid, effectively preventing the clamp from expanding and deforming under high pressure, ensuring a tight seal.

Applications: High-pressure homogenizers, ultra-high temperature sterilization (UHT) systems, hydraulic test cells, etc.

Special Accessories And Components

Blind Nut With Chain – Prevents Parts From Being Lost And Facilitates Management

Description: A wing-shaped blind nut is permanently attached to the clamp’s hinge pin via a small chain.

Function: Prevents parts from being lost—during frequent disassembly and cleaning, the blind nut won’t be misplaced or dropped into dirty areas. Easier to manage—The nut and clamp are integrated into a single unit, making it easy to inventory and store, improving work efficiency and compliance.

How To Choose The Right Sanitary Clamp and Clip Fitting?

Selection Based On Process Media (Corrosivity, Viscosity, Temperature)

The process media is the primary factor in determining the clamp material and surface treatment.

Corrosiveness:

For common media (water, milk, low-sugar liquids): 304 stainless steel is an option, as it offers basic rust and corrosion resistance and offers a high cost-effectiveness.

For corrosive media (acidic/alkaline products, acid/alkaline solutions used for CIP/SIP cleaning, and chlorine-containing solutions): 316L stainless steel is essential. Its added molybdenum significantly improves pitting resistance against chlorides and various chemical media, making it a standard feature in highly corrosive workstations in the pharmaceutical, chemical, and food industries.

Special Media: In extremely corrosive environments (such as certain strong acids or lithium bromide solutions), clamps made of specialized materials such as Hastelloy or titanium may be necessary, but this is rare.

Viscosity and Fluid Properties:

For highly viscous, easily sticky materials (such as jams, syrups, and pastes), a higher level of internal surface smoothness is required for the clamp. Choose products with a high-grade electrolytic polish (e.g., Ra ≤ 0.8µm or even Ra ≤ 0.4µm) to prevent material buildup and facilitate cleaning.

Temperature:

The temperature of the medium directly influences the choice of seal ring, but it also affects the performance of the metal itself. While stainless steel has a wide temperature resistance range, long-term operation at high temperatures requires ensuring that the overall structure of the clamp can withstand thermal stress and potential creep. In this case, a more robust three-piece or bolted clamp is a more reliable option.

Selection Based On Operating Pressure And Temperature Ratings

Selection Based On Installation Space And Operating Frequency

This is crucial for ease of operation and efficiency.

Installation Space:

Ample space: All types of clamps are suitable.

Narrow or confined spaces (such as densely packed equipment or pipes close to walls): Single-pin clamps offer significant advantages, requiring only single-sided access. Quick-release lever clamps are also a good space-saving option.

Frequent Disassembly:

Frequent Disassembly (e.g., multiple times per shift): For workstations that require frequent opening for cleaning, filter element replacement, or pipe adjustments, speed is crucial. Single-pin clamps or quick-release lever clamps are preferred, offering a “one-touch release, one-press lock” design, significantly improving efficiency and reducing labor intensity.

Permanent or Semi-permanent Connections: For connections that rarely require disassembly, either double-pin clamps or bolt clamps are suitable, prioritizing connection reliability and a durable seal.

Relevant Standards And Certifications

Standards and certifications are the cornerstones of ensuring interchangeability, quality, and compliance for clamps.

Dimensional Standards (Ensuring Interchangeability):

ISO 2852: The International Organization for Standardization’s standard for sanitary clamps and fittings, the most widely used worldwide.

DIN 32676: The German standard, highly compatible with ISO standards, is widely used in Europe.

SMS 3006: The Swedish dairy standard, also a widely accepted international standard.

Choosing products that meet any of these standards ensures they will work seamlessly with fittings and seals of the same standard, avoiding leaks or installation problems caused by inconsistencies in specifications.

Sanitary and Material Certifications (Ensuring Compliance and Safety):

3-A Sanitary Standard: This is the leading certification for sanitary equipment manufacturing. The 3-A symbol signifies that the product is designed and manufactured to fully comply with sanitary guidelines, ensuring easy and thorough cleaning with no dead spots. It is the gold standard for the food, dairy, and pharmaceutical industries.

FDA 21 CFR: Regulations of the US Food and Drug Administration, ensuring that materials used in products (such as stainless steel and seals) are safe and non-toxic when in contact with food or drugs.

EC 1935/2004: EU framework regulation requiring all food contact materials and articles to meet safety standards.

Material Certification: Suppliers should be able to provide a valid material certificate (3.1 Certificate) verifying that the composition of stainless steel (such as 316L) meets standards.

To summarize the sanitary clamp selection process: First, determine the material and surface treatment based on the media; then, determine the structure and locking method based on pressure and temperature; then, optimize the specific model based on space and frequency; and finally, use relevant standards and certifications to screen qualified suppliers and products. Following this process, you can make the most accurate and reliable selection.

FAQ

What Is The Difference Between Sanitary Clamps And Standard Industrial Clamps?

Sanitary clamps are designed for easy cleaning, corrosion resistance, and no dead angles. They are made of highly polished stainless steel and meet strict hygiene standards. Industrial clamps focus more on strength and cost, have a rough surface, may have gaps and exposed threads, and are not suitable for sanitary environments.

How Should I Choose Between Single-Pin, Double-Pin, And Bolt Clamps?

For speed and convenience, choose a single-pin clamp.
For general use, balance, and centering, choose a double-pin clamp.
For high pressure, high temperature, and vibration, choose a bolt clamp.

How Is The “Hygiene” Of Sanitary Clamps Reflected?

The “sanitation” of sanitary clamps is reflected in the material, surface, design, and certification.

Materials: Non-toxic, corrosion-resistant 316L stainless steel.
Surface: High-quality electrolytic polishing reduces microbial adhesion.
Design: No dead corners or gaps, self-draining design facilitates thorough cleaning and sterilization.
Certification: Certified by health authorities such as 3-A.

What Precautions Should Be Taken When Installing Sanitary Clamps?

1. Ensure the seal is the correct type, intact, and properly seated.
2. Check that the pipe end faces and seal grooves are clean and free of foreign matter.
3. Align the pipes so that the two clamps close naturally.
4. Tighten the wing nuts or bolts evenly to avoid overtightening on one side, which may cause leaks or damage the clamp.

How Can I Judge The Quality Of A Sanitary Clamp?

Check the material: Clearly marked 316/316L stainless steel.
Touch the surface: The inner and outer surfaces are mirror-smooth, free of scratches or burrs.
Test operation: The hinge pin rotates smoothly without binding; the wing nut or lever provides a clear, moderately firm tightening and unlocking feel.
Check the markings: The brand, material, and standard code are typically stamped on the clamp.

Where Can I Purchase Reliable And Standard-Compliant Sanitary Clamps?

Choose a well-known fluid equipment supplier, authorized distributor, or contact the manufacturer and factory directly. Ensure that they can provide complete material certification, certification, and comprehensive after-sales service.

Conclusion