月度归档： 2015年9月

Automated stem seat valves are workhorses in the sanitary food and beverage process industries and for good reason.  They are versatile, easily cleaned in place, low maintenance and relatively cost effective.  They are available in a wide range of sizes.  Properly applied, they can operate trouble free for long periods. Having said that, if you have spent much time in a sanitary processing facility, you have probably experienced the sound of a sanitary seat valve slam shut resulting in the process line shaking back and forth.  Often this is a result of an improper application of the valve.  Sanitary seat valves are designed to close against the flow (for standard shut off valves, this means in the bottom out the side).  If they are piped with the flow, they will often slam when actuated.

For a standard shut off valve most manufacturers offer a reverse acting model if piping consideration do not allow piping the valve in the optimal position.  For divert valves, this is not always the case.  Sanitary divert valves are used all over sanitary process plants.  Normally they have one inlet and two outlets, allowing flow to go in one of two directions.  This process is often reversed as well. The standard configuration is to have the inlet and one outlet on the side of the valve and the second inlet on the bottom. The valve stem has two seats that operate in the middle part of the valve sliding from one seat to the other to divert the flow.  Using a standard loaded actuator, this configuration almost guarantees that the valve will slam in one the two operating conditions.  How do you fix this?  sansun valve has an answer.

SSD05 is one of the most configurable valve lines on the market.  Their traditional type SSD05 series divert valve has 12 different configurations.  But these all have the same drawbacks as far as their potential for “valve slam”. To solve this problem Waukesha also offers the SSD05 line of sanitary divert valves.  These valves are configured so that all of the ports are on the same plane (8 configurations in all).  The inlet comes into the middle of the valve with the two outlets on the top and bottom (or vice versa for reversed flow)

On the SSD05 divert valve, the valve stem goes from the actuator all the way through the valve body.  Both ends are sealed with an o ring.  This allows the valve seats to be in both the upper and bottom chambers of the valve, allowing the seats to close against the flow at all times.  The result, no slamming!

You are going to pay a little more for the sansun sanitary divert valve than you would for the SSD05.  But isn’t that well worth it to keep your process lines from shaking all over the place?  We think so, considering excessive vibration can lead to instrument damage and inaccuracies.

The sansun sanitary valves are available in sizes 1” through 6”.  This is an extremely well built product.   The W60 valve is very modular.  All of the valve bodies are machined from bar, not castings.  This results in a very wide choice of configurations.  There are also multiple seat material options as well as a very large choice of controls/switch options. Control tops for the entire SSD05 series have also been modularized, with the SSD05 using the clear WCB top also found on the other SSD05 seat valves, the SSD15 mixproof valves, and even the 200 series butterfly valves.

So if you are looking to use automated seat valves in your process and you would prefer your pipes not to shake, consider the sansun when it comes to divert valves.  If you have questions on this topic or any other topic regarding sanitary process, contact one of our sales engineers.  We will do our best to help.

In Europe and the UK, the term sanitary piping defines the plumbing used to convey potable water systems as well as waste water generated downstream of those water systems, i.e.  the plumbing used to bring water into your house and the associated waste plumbing.  These systems can be made from carbon steel pipe, PVC pipe or copper tube.   Other English speaking countries such as Australia and New Zeeland also refer to sanitary piping in this way.

The term hygienic piping in these countries refers to the highly polished, stainless steel high purity tubing systems used in process piping in biopharmaceutical, food, beverage and dairy facilities.  All of the different hygienic systems have special connections designed to allow the systems to be cleanable and eliminating bacterial entrapment areas.

3000 miles to the west, in North America, linguistically we take a different approach.  You rarely see the term hygienic piping used.  Instead we use sanitary piping as a dual purpose term.  It refers to both high purity systems as well potable water and waste water systems.  Does it make sense to use the same term in conjunction with the high purity piping systems used in pharmaceutical plants as well as the plumbing in your house downstream of the bathroom?  Not really.  But that is what we do.

There are some difference between European hygienic fittings/piping and the North American sanitary high purity fittings/piping.  But they have a lot of things in common.  They are all either 304 or 316L stainless steel thin wall tubing  The buttweld connections are designed to be TIG fusion welded together.  They all have interior surface finish finishes polished to precise specifications.  Their mechanical connection systems are designed to yield a crevice free joint that is cleanable and has no areas for bacterial entrapment .

This is Considered Part of a Sanitary Piping System in both the US and in Europe

It seems to us that the European practice of delineating the terms hygienic piping and sanitary makes more sense than the North American practice of throwing all of these terms for sanitary piping in the same bucket.  But we don’t make the rules, we just play by them.  Either way, if you need help with hygienic, sanitary high purity piping systems, contact us.  We are pretty good at this.

Its excellent resistance to aggressive environments, wear and direct sunlight makes it suitable for either indoor or outdoor use.

The butterfly valve can be operated automatically with an actuator or manually with a handle.

The handle blocks the valve in the “open” or “closed” position, although there are also other models with intermediate positions.

The actuator transforms the axial movement of the piston into a 90º rotary movement which it transmits to the disc.

Other options for the butterfly valve are multiposition handle, mini multiposition handle, 4-position handle, 2-position handle, lockable handle, micrometric handle, pneumatic actuator.

Butterfly valves, whether manually or automatically operated, can be used in most liquid product applications in the food-processing, pharmaceutical and chemical industries.

Users of sanitary stainless steel fittings, tubing, valves and various other types of sanitary process equipment are presented a wide variety of interior surface finish choices in today’s marketplace.  What is considered clean, hygienic or sanitary in some markets may not be in others. Add to that the fact that the terminology of measuring surface finishes has changed over the years and you end up with a lot of confused users.  We will try to bring some clarity to these issues in this post.

History

The world of sanitary process tubing, fittings and process equipment originated in the dairy industry.  Over time these products have migrated into a multitude of other industries including food, biopharmaceutical, beverage, personal care and other industries concerned about cleaning their process systems.  For years surface finishes were measured by the grit rating of the final abrasive used in the mechanical polishing process.  What was acceptable in the food and dairy industry was 150 grit.  Pharmaceutical users often specified 180 grit or higher.

As profilometers became commercially available, surface finish measurement started to be categorized by measuring the final surface finish itself.  A profilometer is an instrument that measures the actual metal surface by dragging a stylus across the metal a predetermined length, measuring the distance between the peaks and valleys of the surface.  Initially the values were stated using the RMS (Root Mean Square) method.  Eventually the industry standardized on stating the values in RA, and arithmetic average. Ra values are generally 11% less than RMS values.  In the US Ra is measured in micro-inches, in other
parts of the world in micro-meters.

Surface Finishes:   Ra vs.  Grit

Ra(micro-Inches)             Grit

32                                           150
20                                           180
15                                           180+electropolish
10                                           240+electropolish
10                                           320
5-10                                       320+electropolish

Today

The standard sanitary internal surface finish in the food, dairy and beverage markets is 32Ra.  This has been determined by the 3A (the organization that sens standards for the dairy industry) to be the minimal standard for piping.  The pharmaceutical industry uses a broader range of surface finishes as determined by the end user.  Most biopharmaceutical company specifications now adhere to the ASME BPE standards.  The ASME BPE categorizes 7 different surface finishes, 4 for mechanically polished fittings/tubing and 3 for mechanically polished plus electropolished.

Mechanically Polished

Surface Designation       Maximum Ra

SF0                                         No finish requirement
SF1                                         20Ra
SF2                                         25Ra
SF3                                         30Ra

Electropolished

Surface Designation       Maximum Ra

SF4                                         15Ra
SF5                                         20Ra
SF6                                         25Ra

ASME BPE standards have additional standards for acceptability as well as standardized dimensions.

Today there are a broad variety of sanitary fittings and tubing on the market available with 32Ra interior surface finishes, included buttweld and many different types of sanitary clamp connections. ASME BPE fittings are commercially available in the SF0(no polish),  SF1(20Ra) and SF4(15Ra+electropolish)as standard in both buttweld and sanitary clamp configurations.   Other surface finishes would normally require a special order.   Ironically, commercial sanitary tubing is no longer offered in 32Ra.  The tubing manufacturers have honed their manufacturing processes to the point that the minimum surface finish they offer in 20Ra, considerable better than the minimal 3A standards.