Like so many pieces of plant equipment, valves show their true value when you don’t notice them at all. If you do notice them, it’s probably a sign of danger, downtime, or other assorted difficulties.
These three “d’s” spell trouble for the plant, and bad business forf the manufacturer. Genentech has two ways of monitoring the health of its valves, says Barkley Flynn, supervisor of sterilization, cool ops, and metrology at the South San Francisco facility. One is quarterly inspection of each valve. “This is highly labor-intensive,” Flynn admits. More recently, as part of its performance-based monitoring strategy, Genentech has implemented a wireless system by which it can constantly monitor valve functions. For steam valves, for instance, it gauges temperature drops; for cool ops, it looks at amp draw on compressors. If measurements exceed established control limits, an alarm is triggered and a master mechanic assesses the situation to see if the valve is sticking or truly wearing out.
Flynn says it’s all part of a strategy to get out of the “fire-fighting” business. “The idea is not brilliant,” he says. “It’s just taking the steps needed to push predictive maintenance.” Flynn estimates the payback for such monitoring is three to seven months. In many cases, operators would sooner replace a perfectly good valve than take the risk of it malfunctioning, and so monitoring the health of valves allows the company to extend the life of these pieces of critical equipment.
What does Flynn like in terms of today’s valves themselves? There’s a dizzying array of technologies on the market, he admits, from control to on-off valves, from those for delicate sanitary processes to robust industrial needs. One of the most critical factors he uses to select products is ease of installation—“Do I have to shut down my manufacturing system for a week, or can I do it without interrupting the process?” he asks. Cost and validation issues also factor in.
A good pharma valve has changed a lot over the years, says Charles O’Donnell, marketing manager for Emerson’s Baumann control valve product line. Polished internal components, sanitary seals, and good drainability are still essentials. One trend O’Donnell has seen of late is a movement towards smaller, lighter products, to conform to the needs of moveable process skids and flexible manufacturing. “It’s something we keep in mind whenever we develop a new product,” he says. Another trend is designing valves with simplicity in mind—fewer curves and angles, for example—so that each valve will conform to various end connections and lend itself better to overall versatility, O’Donnell adds.
And, as Flynn noted, monitoring is critical. O’Donnell says that Baumann valves come equipped with Fieldvue digital valve controllers (DVC’s) that pass information about critical parameters on to the manufacturing control system. “Especially in a validated environment, you really need to know what’s going on with your valves,” he says. “You need a system that can give you an indication that there could be a problem, and point you to where the problem may lie.”
With so much competition out there, valve manufacturers are bending over backwards to distinguish themselves. What follows is a survey of some of the latest technologies available, in valves large and small, for plant and process operations:
GEA Tuchenhagen’s VESTA line includes sterile valves for tank bottoms, multiport operations (photo), control, and standard two-way valving—useful pretty much anywhere in pharma clean rooms, says Dave Medlar, company president. One valve range can be used for clean steam control, WFI, CIP, fermentation, etc.
What separates the VESTA from traditional diaphragm valves is its PTFE bellows technology that substitutes for a traditional membrane and, Medlar says, ensures that the valve interior is hermetically sealed off against the atmosphere. It’s also “pocket free,” he says, making for easy sterilization.
GEA developed the bellow technology for applications in other industries and translated it to pharma. It’s still somewhat new to pharma and requires a “leap of faith” for pharmaceutical professionals to buy in, Medlar says. “People in the industry are so used to diaphragms—it’s ingrained in their minds,” Medlar says. “When something else comes along, it takes a few years to catch on.”
Aquasyn makes and markets high-purity diaphragm valves specifically for the drug industry. “Most companies took their existing technologies and made them stainless steel for the pharmaceutical and biotech industries,” says operations manager Dean Richards. “We went out and talked to customers about what their requirements were, and then made our products specifically for them.” One departure from the norm is what the company calls Tork-Tite feet that establish metal-to-metal contact from bonnet to the valve body, eliminating the chance for overtightening and damage to the diaphragm, Richards says. Aquasyn valves range from ¼-inch to 6-inch, for applications ranging from fermentation and chromatography to CIP and WFI.
ASCO Numatics, a division of Emerson Industrial Automation, recently introduced the Numatics Foundation Fieldbus H1 Valve Manifold, an automated product for on/off valve needs in the life sciences. It’s the only valve manifold on the market with Fieldbus H1 protocol capability, says Bill Reeson, the company’s senior marketing manager for the process control industry. A manufacturer will usually have so many on/off valves that it’s too expensive to control them all via Fieldbus. The manifold eliminates this concern for many manufacturers. “The only limitation is how many I/O controls you have,” Reeson says. “Each manifold is one Foundation Fieldbus node, and it can automate up to 16 on/off valves.” Plants with sufficient control channels, or segments, can get away with using just one control network, he says.