Measuring and accurately monitoring process conditions is essential in high purity applications. In the over sixty years Holland has spent applying process equipment for the high purity industry, we’ve learned that the process is the product. If we can’t control the process, we can’t control the final product. Today, we’ll take a little time to talk about sanitary RTDs, what they do, how they work, and how we can apply them.
Resistance temperature detection or RTD is a century old technology. The application of the tendency of electrical conductors to increase their electrical resistance with rising temperature was first described by Sir William Siemens in 1871. This phenomenon is known as thermal resistivity.
RTD’s leverage this concept through the use of a resistive material attached to leads. The resistive material most often used, especially in sanitary and critical high purity applications, is platinum. Other materials used include copper and nickel. Copper and nickel are generally used in less critical applications due to limited resistive linearity and narrow temperature ranges which can lead to inaccuracies.
For this post, we will focus on platinum RTDs or PRTDs. The common values of resistance for a platinum RTD range from 10 ohms to over 1000 ohms. The most common value is 100 ohms of resistance at 0 C. The temperature coefficient of platinum wire is 0.00385. For a 100 ohm wire, this corresponds to a gain of 0.385 ohms/ degree C.
In a PRTD the platinum sensing element is located in the tip of the temperature sensor that is exposed to the process and is connected to wire leads. The sensing element responds to temperature by generating a measurable resistance change that increases as the temperature increases. An RTD is usually provided with either one or two elements in one sensor sheath. Dual elements provide a redundancy that can be used by a temperature transmitter for hot back up, drift monitoring, or to provide inputs to two independent controllers. The sensor sheath is generally made of stainless in a food or pharmaceutical application. The RTD sheath can be directly immersed into the process or inserted into a thermowell. Future posts will take a closer look at thermowells.
The sensing element is connected to wire leads. A single RTD can have two, three, or four leads and a dual RTD can have four, six, or eight leads. The sensor leads connect the sensor to the terminal block, transmitter, or any other termination point. The lead length usually varies by vendor and user requirements.
As mentioned previously, RTD lead configurations are generally offered in three standard configurations: two, three, or four leads. Two wire configuration is simple, but offers no compensation for resistance losses in the lead wire since the lead wires are in series with the element and appear to the transmitter as part of the sensor’s resistance. This leads to inaccuracies.
In three-wire configurations, a third wire is used to compensate for lead wire resistance. The idea is that the third wire will have the same resistance as the other two and the same compensation can be applied to all three wires.
For the highest accuracies, a four-wire RTD is used. A four wire design uses a small amount of current applied to two of the wires and the voltage developed across the sensor is measured over the other two wires with a high-impedance, high resolution measuring circuit. The high impedance eliminates current flow in the voltage measurement leads and therefore the resistance of the leads is not a factor.
Much more can be said about RTD construction and options. Future posts will focus not only on the specific products we offer, but also on thermowell and transmitter selection. If you’d like to skip the wait, call us today and we’d be happy to help you with your next temperature application.
We had a post last week that went over what a hazardous location is and how they are classified. With today’s post, we will expound on that topic and discuss the different electrical enclosure types, what they are, and where they are used.
To begin our discussion of electrical panel enclosure, it is helpful to remember what makes things sanitary. One of the keys is that the equipment must be cleanable. This doesn’t only mean that it can be taken apart or cleaned in place. In a lot of food and beverage applications, this means that the equipment may be hosed down or subject to direct water spray. It could also mean that the enclosure is located outside or in a location classified as hazardous. Many facilities are damp, or dusty, some are even exceptionally hot or humid. All of these conditions can wreak havoc on electronics. At Holland, we’ve been helping customers select both the correct process equipment and enclosure type for over sixty years. The following is a brief overview of the types of enclosures we commonly specify for high purity applications and when they should be used.
The National Electric Manufacturers Association (NEMA) specifies the following enclosure types for non-hazardous locations when completely and properly installed:
Type 1 Enclosures are constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts and to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt). This enclosure is the most basic and should only be used in light duty applications. Generally, we’ll see these types of electrical enclosures used as a sub component mounted within a larger enclosure.
Type 2 Enclosures are pretty comparable to Type 1 enclosures, but are designed to provide a degree of protection against water. The water resistance is limited to light splashing. It is not designed to protect against direct spray.
Type 3 enclosures (Including 3, 3R, 3S, 3X, 3RX, and 3SX) are primarily suited for outdoor use. They are designed to prevent the ingress of water, such as rain, sleet, and snow, and also be undamaged and operate when ice laden. This enclosure type is available in high corrosion resistant types as well (3RX and 3SX).
Type 4 enclosures are much more common in high purity applications. Type 4 enclosures are constructed for either indoor or outdoor use to provide a degree of protection of the equipment inside the enclosure against the ingress of solid foreign objects; to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water. This includes rain, sleet, snow, and splashing water but is differentiated from NEMA 3 enclosures in that it is designed to guard the internal components against direct hose spray. This is a true “wash-down” enclosure.
Type 4X enclosures are probably the most common type of enclosure we specify for the harsh environments of a food or beverage process plant. A lot of times we’re coupling a wash-down duty motor with a NEMA 4X drive. The 4X duty rating is comparable to Type 4, but adds an additional corrosion resistance benefit not seen with Type 4 enclsoures.
We generally don’t see Type 5 and 6 enclosures very often in the high purity industry. Type 5 enclosure does not offer the same dust protection of Type 4 and 4X, and Type 6 is designed for occasional water submersion, also a condition we generally don’t have to satisfy.
Types 12, 12K, and 13 are designed for applications where there may be oil or coolant seepage. These are more common than full water submersion, but we still don’t specify them often.
To conclude, the enclosure type selection is critical when specifying a new piece of process equipment. Optimal enclosure selection is essential for not only maximizing equipment life, but also increasing operator safety. Remember, all of the about ratings are for Non-Hazardous Locations. Future posts will focus on the ratings for Hazardous locations, as well as considerations and constructional difference of enclosures designed for indoor/outdoor use. If you have any additional questions about which enclosure type is right for you, contact a Holland Sales Engineer today.
Whether it is top entry, bottom entry or side entry, all traditional sanitary mixers/agitators have one thing in common- they all have some type of mechanical seal, separating the vessel interior from the outside environment where the impeller shaft enters the vessel. These can range from a very simple single mechanical seal to very sophisticated (and expensive) seal arrangements designed to maintain a sterile barrier. But they all have one and without proper maintenance they will all fail sooner or later, potentially exposing the contents of the vessel to the surrounding environment. If you want to eliminate this possibility there is now a readily commercially available alternative; the sanitary magnetic mixer, or mag mixer.
Sanitary mag mixers have no mechanical seals. Most consist of three main components:
- A 316L stainless steel mounting plate that is welded into the vessel.
- An impeller that mounts onto a spindle on the weld plate. The impeller has magnets mounted to it.
- A drive unit. The drive unit connects to the bottom of the tank. The drive has a powerful magnet mounted to the output shaft.
The sanitary mag mixer is a relatively simple device. The impeller mounts onto the weld plate on a spindle that has a bearing on it. Different manufacturers have different bearing designs, the most common is to use a hardened material as a thrust bearing. The drive unit locks to the bottom of the weld plate. When the drive rotates, its magnet locks onto the magnet in the impeller causing it to turn. Like we said, simple.
What are the advantages of the mag mixer over tradition type mixers? The biggest advantage is sterility. There is no seal. In critical applications such as bioreactors this is really important. Seal failure can be catastrophic. This is equally true in many other pharmaceutical sterile mixing applications.
There are other advantages as well. Because they are bottom mounted, sanitary mag mixers don’t require the head space that traditional mixers do. Also, sanitary mag mixers will mix until the vessel is almost completely empty, often not the case with traditional agitators.
How well do sanitary mag mixers agitate? Very well. We have tested them in our facility and on low viscosity liquids we have had no problem creating a vortex in vessel. The units come in multiple sizes that will cover vessels ranging from as small as 10 liters up to 10,000. They can be used on higher viscosity liquids as well. You should consult a representative of the mixer company to get a unit properly sized for your application.
Can you CIP a sanitary mag mixer? Yes you can. We normally sell the Steridose Sterimixer. Steridose brought the first commercial sanitary mag mixer on the market and in our opinion, offer the most compelling product. They offer two impeller designs. Both are CIP/SIP capable. One has a more open design that is suited better for hard to clean products.
So if you need a vessel with a mixer and you want to ensure sterility, or have head space problems or simple don’t want to deal with mechanical seals consider the sanity mag mixer as an alternative. If you have a specific need and would like to discuss it, contact us and go over your application with one of our sales engineers. We are here to help.
Do You Want Us to Make a Sanitary Fabrication for You? Here are a Few Questions We Would Like Answered in Order to Help You.
We custom fabricate all sorts of sanitary process assemblies. That’s our business. We build thousands of fabrications per year from simple sanitary spool pieces and jacketed fittings to complete sanitary manifolds pre-fabricated sanitary piping systems, and even turn key skids and modules. In order to get you a quick, accurate proposal, there are a few common pieces of information we need. We thought we would use this post to go over some of these items.
- Can you give us a brief description of what you want built and what you are doing with it? Even if you don’t have a drawing give us a decent description we can probably put a quote together. If you decide to move forward, we will draw it for you.
- What material do you want the sanitary fabrication made from? The most obvious choices are 304 or 316L stainless steel. But we can also fabricate items in Titanium, AL6XN or Hastelloy.
- Do you have a surface finish requirement? We have extensive in house polishing capabilities and can build items with RA values as low as 10RA. We need to know both the ID and OD surface finish requirements.
- Do you want the welds ground out and polished or left as is? We normally can grind all of the welds, but it adds cost.
- Do the sanitary fabrications need to be electropolished?
- Do they need to be passivated?
- Is there a welding requirement? Some customers want all joints to be made by computerized orbital welders. Some do not care. This also affects the cost.
- What are your documentation requirements? We offer a fully menu of documentation for our sanitary fabrications, but many come with an added cost. These include:
- Material Test Reports
- Positive Metal Identification (PMI)
- Inbound fitting/tubing inspection
- Weld maps/logs
- Welder Certs
- Passivation Certs
- Electropolish Certs
- Ferrite Testing Certs
So if you have all of this information up front it will speed up the quotation process and we will be able to get you a proposal faster. If we have to track you down to get the answers it will slow the process a bit. Once we get a proposal made and you decide to purchase you sanitary fabrication from us (Why wouldn’t you? You seem pretty smart.), we will provide you with an approval drawing for you to review before we proceed with fabrication. The drawing will include all of this information. The only time we wouldn’t provide a drawing is if we are working off of one yours. This isn’t because we’re lazy- we just don’t want to miss any details on your original print. If you do provide a drawing, we will clarify any issues or discrepancies we find.
Don’t worry, even if you do not have all of this information available, we can help. Contact one of our sales engineers. We can walk through your application with you and make some recommendations. We do this every day.
Sanitary Batching and Basic Automation in High Purity and Food Processing- What is it and what are your options?
This post will be a first in a series of sanitary batch system offerings and case studies that clearly outline the tangible results customers get from using Holland’s products and services.
In today’s process world, there are a few key buzz words that will almost always get you a meeting with a prospective customer: return on investment (ROI), continuous improvement, increased product yield, just to name a few. As we’ve discussed in previous posts, we’ve been helping our customers identify solutions to complex processing solutions for over 60 years. In fact, this one of Holland’s key value propositions. We are not a buyer and reseller of goods. We are able to add value to each piece of sanitary process equipment we sell by being at the forefront of industry technology and leveraging that knowledge to develop and bring to market compelling, complete process solutions and make it easy for both our customers to do business with us and provide a level of comfort critical to long lasting business relationships.
One area of sanitary processing Holland has identified as a market where we can really help our customers is with complete, turnkey batch systems and basic automation. Not everyone needs an expensive and complex PLC or DCS. Pump run, valve cycling, turbidity control, and fill bowl level control are all good examples of basic functions almost every producer uses that can be readily automated to provide increased throughput and product consistency.
We’re not the only ones who have identified this market need. Many of our channel partners have also marketed the advantages of their products and how they can be integrated with other components to create a turnkey system. The problem is that pump manufacturers have a lot of experience specifying sanitary flow meters, meter guys don’t have a lot of experience selecting drives, and no one has the systems experience to integrate all of these components to create a compelling process solutions. When you discount the value of proprietary product knowledge and manufacture and place a premium flexibility, quick response, and broad product knowledge, it quickly becomes apparent that companies like Holland are uniquely positioned to bring integrated product solutions to market.
So what is batching and why is it important? Sanitary Batching systems create an economical and safe way of controlling the amount of product that flow through a system. Batching and automation allow us to assemble multiple ingredients to create a product based on a recipe. This is advantageous for the following reasons:
- Operations that are dependent on humans for executing manual, repetitive tasks are subject to variability. Product quality hinges on this
- Manufacturing capacity if determined by volume and manufacturing time. You can increase the volume of product you can handle, or you can reduce your processing and downtime. The ladder is more economical and the advantages offered by batching systems.
- Process optimization- especially in pharmaceutical applications, increasing product yield can be done by making small changes and accurately monitoring process variables. Increased yield means a return on the process equipment investment.
- Record Keeping- batch processes with data loggers allow us to generate detailed records as to how a batch was made and relates all data to a single batch ID. Data of this nature can be very valuable for quality assurance, variability investigations, and process analysis
- Safety- operators spend less time exposed to potentially hazardous process variables when the process is automated as compared to manual control. Less exposure to the process generally results in a safer process.
Now those benefits now are unique to high purity batching and automation applications. They are ubiquitous across industry. What characteristics do we specifically need to target and design for when putting together a sanitary batch system?
- The system needs to be accurate and consistent. In the foods and pharmaceutical industries, we handle a wide range of products whose characteristics very greatly. We’ve handled conductive and non-conductive products, thick products and products with less viscosity than water, and also shear sensitive products. What this means for a sanitary process selection is correctly identifying the meter, pump, and valve types. This also means conditioning the flow for the most accurate process measurements possible
- It needs to be clean and safe. That goes without saying, this is a sanitary system after all. This means orienting meters in the correct position to ensure full drainage, incorporating CIP jumpers around pumps, and using pressure relief valves where necessary
- A system should also be simple, easy to use, and well suited for the environment in which it will operate. For us, that means one power cord and smart component integration. It means using wash down or explosion proof enclosures where necessary and presenting operators with intuitive, easy to use HMI’s that can also be locked out to prevent tampering.
- A system should also be adaptable and well suited for multiple applications and products. That could be portability, as well as using a pump that can handle different products.
So what does a good application for that could be optimized by batching look like? Let’s go over a couple of examples.
One application is basic sanitary metering and ingredient addition. Imagine a yogurt plant with multiple storage tank, each tank holds a separate ingredient. Through the use of a solenoid controlled seat valve manifold, and a single pump, meter, and controller, we can precisely add the proper amount of each ingredient into the receiving or batch tank simultaneously. This increases throughput and cycle time resulting in increased capacity. Holland can also integrate level probes into the storage tanks to prevent pump cavitation and high level probes in the batch tank to eliminate the risk of overfill.
Another example of an application where we feel we can help brewers specifically is with lauter tun control. Following the mashing process, the mash in pump into the lauter tun in order to separate the wort from the malt and spent grain solids. When the malts rests, the grain settles on the bottom of the lauter tun creating a filter cake. Once the grain has settled, the tun is drained and the wort that is pumped has a high solids content and needs to be recirculated through a valve back into the lauter tun for further filtering. The control of this valve is often done manually using a sight glass and an operator to eyeball the solids content. When the wort leaving the tank reaches the proper clarity, it is sent forward to the wort kettle. This is an important process as excessive amounts of husk in the wort kettle can lead to fermentation problems and reduction in overall beer quality.
To solve this problem, Holland can integrate not only the sanitary pump and control valve (be it a seat divert or three way ball valve), but also a turbidity meter to monitor the solids content of the wort. This leads to automatic control of the valve and consistent valve change-over, ensuring desired wort quality. Automatic control eliminates human errors and product waste.
This is just scratching the surface of integrated approach that Holland takes when approaching challenging sanitary process applications to created integrated, turnkey solutions. In future posts, we will take a closer look at the more specific product we offer and how we can use them to solve process problems and work with our customers to increase process capacity, improve product yield, and maximize return on equipment investments. If you have an application you need help with, contact us and we would be happy to offer our help.
When specifying equipment for a new process application, it is not only important to identify pieces of equipment that protect product integrity and are safe for end users (i.e. consumers and patients), but also ensure the safety of equipment users and operators. A major safety concern in industrial plants is the occurrence of fires and explosions. In fact, no other aspect of industrial safety has more codes and standards dedicated to it. The Occupational Safety and Health Administration (OSHA) defines a hazardous location as the following:
“Hazardous locations are areas where flammable liquids, gases, vapors, or combustible dusts exist in sufficient quantities to produce explosion or fire. In hazardous locations, specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances”
Summarily, and for the purposes of this blog post, a hazardous location is anywhere where things can blow up. This post will focus on Class/Division method of hazardous location classification which is the most common method used in North America. Future posts will explore alternative classification systems as well as specific product offerings designed for optimal performance in these challenging applications.
To begin, the NEC defines three distinct classes of the general nature of hazardous materials in the surrounding atmosphere. They are as follows:
Class I: Hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures
Class II: Hazardous because combustible or conductive dusts are present.
Class III: Hazardous because ignitable fibers or flyings are present, but not likely to be in suspension in sufficient quantities to produce ignitable mixtures. Typical examples are wood chips, cotton, flax, and nylon.
The division, the designation which follows the class, defines the probability of hazardous material being present in an ignitable concentration in the surrounding atmosphere. The NEC defines the following divisions:
Division 1: The substance referred to by class is present during normal conditions.
Division 2: The substance referred to by class is present only in abnormal conditions, such as a container failure or system breakdown.
Materials are subsequently divided into different groups. Group A is acetylene, Group B is hydrogen and other combustible fuels, Group C contains carbon monoxide, and Group D has gasoline, acetone and a few others. It is not the aim of this blog to define all groups. Specific hazardous materials within each group and their automatic ignition temperatures can be found in Article 500 of the National Electrical Code. It is important to note, however, that Groups A, B, C, and D apply to class I locations, while Groups E, F, and G apply to class II locations.
In summary, hazardous locations can be described as those locations where electrical equipment might installed and might present a condition which could become explosive if the elements for ignition are present. By understanding the location classification, we will be able to properly select and install equipment that can be safely operated in your process. Holland has over 60 years of specifying equipment for these challenging applications. Contact a Holland representative today for more information about your hazardous location equipment requirements and our explosion proof offerings.
Sanitary gaskets come in a variety of elastomer materials. There are a lot of choices allowing the end user to pick a gasket material that best suits their process needs for chemical compatibility, thermal properties and purity. Yet while there are all of these different materials available, most gaskets come in one of two colors, black and white.
So when you are changing out a gasket, how can you be sure the new gasket you are putting in is the right material? Simple, just look at the color code on the side of the gasket. Most sanitary gaskets come with a series of colored dots on the side of the gasket that signifies the polymer material the sanitary gasket is constructed from. Listed below are the more common color codes.
- Buna: One red dot
- Sulfur Cured EPDM: One green dot
- Peroxide Cured EPDM: Three green dots
- FKM (Viton): One white and one yellow dot
- Peroxide Cured Silicone: One pink dot
- Platinum Cured Silicone: No dot
- PTFE (Teflon): No dot
- PTFE Envelope Gasket with EPDM Core: Three green dots
- PTFE Envelope Gasket with FKM Core: One white and one yellow dot
These codes generally hold true regardless of the gasket material. EPDM, FKM and Buna sanitary gaskets are available in both black and white material. The material color codes remain the same for each material regardless of color and manufacturer. While platinum cured silicone and PTFE sanitary gaskets don’t have a code, this normally presents few problem as the material properties of these gaskets are unique and they are readily identifiable based on visual appearance and tactile touch.
If you want more assurance that you are putting the right material into your process line, special colored sanitary gaskets are available in many materials. If you want to look into this or have any other questions regarding sanitary gaskets contact us and we would be happy to discuss your specific situation. We’re here to help.