What Gets Laboratory Glassware Clean?

Directing the forces that get glassware clean to every surface
is the task of a laboratory glassware washing machine

As mentioned before in a previous posting...."Glassware washing, in the laboratory setting, is an unglamorous but necessary task. Glassware utilized at almost any point in an analytical procedure needs to come with an assurance that there is no residual material left over from any previous use. The operation, if accomplished manually, raises practical concerns about quality control and effective use of valuable human resources."

Understanding how a glassware washing machine cleans your glassware can help in obtaining the best results from machine use. 

Simply described, there are two main cleaning forces or actions at work during a wash program. Dissolution involves the solvent action of water, often aided by chemicals, on contaminates on the wash load. The second major cleaning component is mechanical removal of soils and contaminates, accomplished with impingement (blasting the dirt off with direct spray) and a cascading flow of wash or rinse water.

Looking at these two cleaning forces, there are some other factors that are related to their overall effectiveness.

• Time - Longer cycle times will deliver higher overall levels of load exposure to cleaning forces.
• Temperature - Some types of contaminates are best removed with high temperature wash fluid, others with at least part of the wash program using cooler temperature. 
• Chemicals - The solvent power of the wash solution can be significantly enhanced by using the right chemical additive. Matching wash chemicals to the demands of the wash load is a key element in achieving good results in a reasonable amount of time.
• Contact - Nothing listed above has any impact unless the wash program solution makes full and repeated contact with all surfaces of the load. 

What does all this mean to the lab operator or technician trying to get clean glassware?

It is necessary to know the nature of the soil or contaminates on the wash load. This allows the proper selection of temperature and chemicals for the wash program, and the program sequence. Separating soiled glassware into groups according to wash program is a useful procedure, matching the soil or contaminant with the right program, temperature, and chemicals to remove it.

Loading the washer is also an important step in the cleaning process. Operators should understand how wash fluid flows through the machine and any special processing carriers or racks. Improper loading can prevent sufficient contact between wash fluids and load surfaces, reducing the effectiveness of the wash program.

This is a very general description. Each topic covered has depth and detail that needs to be explored enough to determine an effective wash plan for your lab. Technical help and information is available from glassware manufacturers, wash chemical suppliers, and wash equipment specialists.

Machine Washing of Laboratory Glassware

Laboratory glassware washers with loading racks and glassware
ready for processing
Courtesy Miele Professional

Automation and changes to many laboratory tasks and processes has likely reduced the need for reusable glassware in those tasks. Nevertheless, there remain many applications where laboratory glassware and other reusable items are the mainstay. Employing reusable containers, tools, and a host of other specialized items brings with it a responsibility for properly processing, or cleaning, the items after each use.

The goal of laboratory glassware washing is to remove all traces of the previous tasks in which the glassware was employed.

It's really that simple. Ideally, no traces of anything but glass. Laboratory measurements can be highly sensitive, so meeting the gold standard for clean glassware requires some knowledge and skill.

• Know the nature of the contaminants on the glassware.
• Know how to properly remove those contaminants.
• Establish a procedure that, when properly executed, thoroughly removes the contaminants.
• Execute the procedure in accordance with established steps.

Hand washing is one way to process reusable glassware, and in some special cases may be the best or only available way to accomplish the task. Here are some characteristics of glassware washing by hand.

• Manual operation, completely accomplished with human labor.
• All facets of cleaning operation subject to adjustment, intentionally or accidentally, by the washing technician.
• Process one item at a time, resulting in substantial time commitment to the operation.
• Air dry at room temperature, unless a separate oven is used.
• Potentially, some limitation on exposure of washed items to high temperature water due to supply temperature irregularity or evaporative cooling.
• Extensive handling of fragile glassware can lead to breakage.
• Inventory of brushes, gloves, drying racks, and other items needed for processing must be maintained and replenished as needed.
• Initial investment is low.
• Personnel training component can be high, in cases where high quality work is needed and employee turnover may be a factor.

Glassware washing machines, specially purposed for processing laboratory glassware, can overcome a number of the efficiency and quality concerns that can be associated with manual washing. Here are some characteristics of automated glassware washers.

• Initial investment is high when compared to manual washing.
• All facets of the operation, except loading and unloading, are automated and require no human intervention under normal operation.
• Capable washing equipment provides multiple stored programs with differing washing protocols needed for effectively processing various types of glassware or other items.
• Controller runs and monitors the operation of the machine through selected cycle to assure the correct wash procedure is followed.
• Process multiple items at a time.
• Washing machines can include a heated drying cycle.
• Water temperature is maintained at the proper level throughout the timed cycle phases.
• Inventory of holders, supports, or racks for processing the glassware inventory of the lab.
• Minimized use of human labor for the washing operation.

Each lab operation can choose between either the hand or machine washing methods. Share your lab glassware washing requirements and challenges with lab equipment professionals, combining your own experience and knowledge with their equipment application expertise to develop an effective solution.

Rigid Sided Anaerobic Glove Boxes - Theory of Design

Rigid construction anaerobic glove box with airlock
Courtesy Coy Lab Products

There are numerous threads of scientific research that require small environments with extremely low levels of oxygen. This anaerobic environment requires isolation from the surrounding atmosphere and a means to scavenge trace amounts of oxygen that inevitably get into the closed environment. It is also, in many cases, necessary to provide a means to transfer materials into and out of the chamber during use, as well as to allow operators to manipulate materials within the chamber.

One method applied to remove infiltrated oxygen is through the use of a catalyst within the chamber to react the oxygen with hydrogen, producing water vapor. This can be accomplished with a small fan enclosure that continuously or intermittently circulates chamber air across a palladium chloride coated alumina substrate. The palladium chloride supports the oxygen-hydrogen reaction, while the alumina substrate serves to absorb the water vapor. The fan must be properly sized and operated on a schedule that will treat the chamber atmosphere at a rate that is suitable for the application. Larger fan and catalyst combinations will produce larger turnover rates for the chamber atmosphere, along with faster recovery of anaerobic conditions.

For the movement of materials into and out of the work zone, an airlock is provided. The airlock enables isolation of the chamber interior work zone from the surrounding atmosphere and limits that amount of atmospheric air entering the chamber when materials are introduced to the anaerobic work zone. The capacity of the catalyst system is coordinated with the size of the airlock to provide rapid removal of the known quantity of oxygen introduced to the chamber each time the airlock is cycled.

Sealed glove ports provide an operator with the ability to hold and manipulate the contents of the chamber. Proper maintenance of the gloves and their mounting to the ports is essential to maintaining anaerobic conditions in the chamber. Because some degree of physical stress is placed on the glove mountings during normal use of the chamber, regular inspection of their seals is good practice.

Oxygen will diffuse into the chamber during normal operation. A source of hydrogen gas must be used to provide sufficient quantities to enable effective catalyst operation. A special gas mix can be used to purge the airlock that serves to reduce the oxygen level of the airlock and provides sufficient hydrogen to process the introduced oxygen, as well.

This is but a general description of how the system functions. Share your anaerobic process and research challenges with a product application specialist, combining your own process knowledge and experience with their product application expertise to develop the best solution for your application.

Technical Sales Representatives Add Value

Equipment specialists can help lab and process operators
navigate to effective solutions

Laboratory equipment is often sold with the support of sales engineers working at the local or regional level. Realizing what these specialists have to contribute, taking advantage of their knowledge and talent, will help save time and cost and contribute to a better outcome when specifying, purchasing and installing laboratory equipment.

Consider these contributions:

Product Knowledge: Specialized sales engineers, by the nature of their job, have product knowledge that is both broad and deep. They are also current on new products, their capabilities and their proper application. Unlike information available on the Web, sales engineers can get advanced notice of product obsolescence and replacement options, new technologies coming to the market, and more. Also, because they are exposed to so many different types of applications and situations, sales engineers are a wealth of tacit knowledge that they readily share with their customers.

Experience: Whether a project engineer, lab manager, or researcher, you may be treading on fresh ground regarding many aspects of a major equipment purchase. You may not have a full grasp on how to handle a particular challenge presented by a project. Call in the technical sales rep - there can be real benefit in connecting to a source with past exposure to your current issue.

Access: Through a technical sales engineer, you may be able to look “behind the scenes” with a particular manufacturer and garner important information not publicly available. Sales reps deal with people, making connections between customers and manufacturer's support personnel that may not normally be public facing. They make it their business to know what’s going on with products, companies, and industries.

Of course, sales engineers will be biased. Any solutions proposed are likely to be based upon the products sold by the representative. But the best sales people will share the virtues of their products openly and honestly, and tell you when they do not have the right product for your application. This is where the discussion, consideration and evaluation of several solutions becomes part of achieving the best project outcome.

As a stakeholder in process or laboratory operation, it's highly recommended you develop a professional, mutually beneficial relationship with a laboratory and process equipment specialist, a problem solver. Look at a relationship with the local sales engineer as symbiotic. Their success, and your success, go hand-in-hand.

Controlled Environment Room Air Flow Matters

Matching controlled environment air flow pattern, velocity,
and volume to the application is part of delivering a well
performing system
photo courtesy Percival Scientific

Environmental chambers, whether of the reach-in or walk-in variety, all rely on the movement of air within their controlled space to attain performance specifications. Various manufacturers will employ differing strategies for chamber air movement, and the manner in which their designs disperse air flow throughout a chamber of any size can have an impact on the work or process held within the chamber.

This article is about controlled environment rooms, but much of what is included here is also applicable to smaller sized chambers.

The design of air flow in a controlled environment room can be impacted by a number of factors, some of which may be based on specific application requirements, and others that may be influenced by cost, production simplicity, or other factors unrelated to the performance goal of the equipment.

What aspects of controlled environment room air flow bear on performance?

• Velocity - In the common usage of the term when referring to air flow, the speed of the moving air. Depending upon the air moving equipment arrangement and any dispersion devices, such as perforated suspended ceilings or wall plenums, air velocity can vary throughout a chamber. Users should consider how their work may be impacted by air flow velocity. The storage of material in closed and sealed containers may be impervious to air velocity effects because the "product" within the container is not in contact with the moving air. Plants and insects, on the other hand, are an example of items that may be significantly or severely impacted by air velocity. Higher air velocity at a chamber location exposes that location to more air per unit of time. Desiccation is one possible concern that is exacerbated by increased air velocity. Higher velocity can also be beneficial, even necessary, for some applications. Rapid cooling or heating of materials placed within a chamber is enhanced by increased air movement across the material surface.
• Volume - The volumetric flow of air through a controlled space or chamber is needed to transfer heat to or from the space in order to maintain temperature control. Much of the air in a controlled environment room is recirculated, with cooling, heating, and in some cases moisture applied to condition the air in the room to the setpoint. The volume of air movement is loosely related to velocity, so increasing volume will result in an increase in velocity unless other design changes are made with respect to how the air is dispersed throughout the room. Higher volume, or turnover rate, contributes to better temperature uniformity in the room. As with velocity, there may be application specific requirements for low air movement. Keep in mind that low air movement creates challenges to the attainment of close temperature control and uniformity. 
• Pattern - The way in which air is distributed throughout the controlled environment room can impact system performance once materials are placed in the room or process work is commenced. Empty chambers generally perform well, regardless of the air flow pattern, because there is little in the way of a load on the system and no solid materials in place to block or redirect air flow. Consideration should be given to the way in which air is dispersed throughout the work area. Loading patterns for stored product or the placement of work in process should be accommodated by the air flow pattern.

Matching the right air flow characteristics to the work to be achieved in a controlled environment room will result in better overall performance, not just when empty chamber tests are conducted, but when real work is being accomplished. 

Share your environmental chamber and controlled environment room requirements and challenges with application experts. The combination of your own experience and knowledge with their specialized technical expertise will yield an effective solution.