Solenoid Operated Isolation Mini-Valves

Posted on April 24, 2012 by JohnT

AVAILABLE NOW! Bio-Chem Fluidics Isolation Valves are solenoid-operated devices.  The valves use a flexible diaphragm to isolate the solenoid actuation mechanism from the fluid path. When the valve is energized, the solenoid retracts an armature that is attached to a flexible diaphragm. In a normally-closed valve, this raises the diaphragm allowing fluid to flow between the inlet and outlet ports.

The 038T range of Mini-Valves are normally-closed isolation valves that fill a specific need for controlling extremely low flow rates (Cv values of 0.006 and 0.011) with a valve that’s compact and has very low power consumption.

Bio-Chem Fluidics 038T2S and 038T2B Mini-Valves

Bio-Chem Fluidics 038T2S and 038T2B Mini-Valves

Features of the Bio-Chem Fluidics Isolation Mini-Valve:

  • 12 volt or 24 volt DC solenoid
  • Choice of configuration Side or Bottom 1/4-28 UNF threaded ports
  • Inert fluid path with only two wetted components made entirely from chemically inert materials
  • Choice of materials -(read more – Plastics & Polymers Reference Page) Body materials: PTFE or PPS; Diaphragm materials: PTFE, FFKM, EPDM
  • Choice of valve orifice sizes – 0.032” (0.81 mm) or 0.054” (1.4 mm)
  • Low power consumption – power consumption is a low 2.0 Watts at 12VDC or 24VDC
  • Bi-directional flow – can be used with flow in either direction
  • Manifold mounting option – can also be supplied in a manifold mount configuration

Bio-Chem Fluidics Isolation Mini-Valves are available for purchase online via our Isolation Valve page at the main website. For more details please call 973-263-3001.

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Flow Selection Valves for Flow Mixing and Stream Splitting

Posted on February 24, 2012 by JohnT
080T6 Flow Selection Valve

080T6 Flow Selection Valve

Bio-Chem Valve ™ Flow Selection Valves are similar in construction to Bio-Chem Valve™ solenoid operated Isolation Valves and combine multiple valve actuators into a single, compact unit. Because each actuator operates independently, Flow Selection Valves can combine or select any combination of between 2 and 8 individual source streams. Valves are situated around a central block, providing flow paths of equal length. Read more in the Flow Selection Valve brochure.

Flow Selection Valve cross-section

Flow Selection Valve cross-section

A flexible diaphragm isolates the solenoid actuation mechanism from the fluid path. When a valve is energized, the solenoid retracts the armature that is attached to the flexible diaphragm. This raises the diaphragm allowing fluid to flow between the common port and an outlet. When de-energized a spring forces the diaphragm down, closing off the flow path.

Because the fluid path can be made from extremely inert materials (such as PTFE and PEEK), Bio-Chem Valve ™ Flow Selection Valves are particularly suitable for use in highly aggressive and / or high purity fluid applications.

Why choose a Flow Selection Valve?

  • Eliminate tubing between valves: Bio-Chem Valve™ Flow Selection Valves eliminate the need for tubing sets to connect between individual valves thereby reducing the number of connections and potential leak points.
  • Equivalence of internal flow paths: Unlike linear manifolds or valves connected by tubing sets, Flow Selection Valve flow paths are all the same length which means they have equal pressure drop, equal response times and equal internal volumes.
  • Individual control of flow paths: Unlike other valves with multiple ports, each flow path has its own associated actuation mechanism and can be controlled individually. This means that there is no need to pass one port to connect to another as with rotary valves.
  • Economic considerations: Flow Selection Valves offer an economic alternative to either: a) multiple single valves and their associated, necessary tubing sets, or b) multi-port valves that require sophisticated control systems for operation.

Read more in the Flow Selection Valve brochure.

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Isolation valve applications for analytical instruments

Posted on January 19, 2012 by JohnT

#1 Precise, repeatable dispensing of reagents

Isolation valve application

Precise, repeatable dispensing of reagents

Maintaining a repeatable dispense of aggressive (and often very expensive) reagents into an analytical instrument can be problematic with conventional pumping equipment.

Some forward thinking instrument designers have abandoned the concept of using a pump and have instead turned to using a Bio-Chem Fluidics Isolation Valve.

In such applications, a standard 2-way normally closed isolation valve is connected to a dip tube, which is inserted into the bottom of a reagent bottle. Low pressure nitrogen (or other appropriate inert gas) is introduced seperately to blanket the volume above the liquid in the reagent bottle. The pressure inside the bottle (maintained precisely at a calibrated low value) is sufficient to force the reagent liquid up the dip tube.

Under “normal” conditions, the valve is not energized and remains closed so there is no flow.

When the valve is energized the diaphragm opens and flow through the valve is established. The isolation valve now becomes a very repeatable fluid dispenser – the amount of liquid dispensed is dependent only on the time the valve is open.

#2 Aspirate and Dispense (“sip and spit”)

Isolation valve application

Aspirate and dispense

Sometimes the volume of liquid to be dispensed needs to be either a) very small, b) extremely precise or c) both. In these situations it is very common to use a precision machined syringe to control the dispense volume.

Bio-Chem Fluidics 3-way Isolation Valves are commonly used as the link between the liquid reservoir, the syringe and the instrument. A 3-way valve has three ports; normally open (NO in illustration), normally closed (NC) and common (Com). The common port is connected to the syringe. When the plunger is withdrawn, the valve is not energized and the flow is between the reservoir and the syringe via the NO port (aspiration or “sip”).

When the syringe is pushed in, the valve is simultaneously energized. The flow path switches to the to the NC port, which is connected to the instrument (dispense or “spit”).

Although standard threaded port valves are common in this application, Bio-Chem Fluidics can, as an option, supply valves with luer fittings to allow direct coupling to the syringe (contact BCF here for more details). Download the Isolation Valve brochure to read more.

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Two Common Applications for Pinch Valves

Posted on January 10, 2012 by JohnT

#1 Prevention of shear in sensitive materials

Pinch Valves are typically used in “on-off” applications; applications that don’t require flow control or modulation – you just want to start and stop the flow.

Complex flowpath through conventional valveConventional on-off valves often require the fluid to be regulated to move through a convoluted / complex flow path, even when fully open. This can be an issue for biological materials (proteins, DNA, etc) which can be easily “sheared” when forced through complicated paths.

Line of sight flow through Pinch ValvePinch Valves offer “line-of-sight” flow paths where the open tube, even if slightly pinched does not significantly block the flow path. Because of the slight venturi effect produced by the pinch, flow through the tubing can actually be enhanced rather than restricted.

#2 Handling of non-liquid effluents

Pinch Valves are often used on the waste side of instrumentation, “dumping” solutions to a collection device or simply out of the instrument. The waste stream can have many components; liquid, particulates, precipitates and coagulations inadvertently formed from mixtures of chemicals. These accumulated non-liquids can lead to coating on the inner surface of a conventional valve. The coating process is uneven and can eventually lead to the valve becoming clogged.

Pinch Valves offer a three-fold solution to this problem:

1.         The tubing can be pre-treated to prevent the build-up of films. Bio-Chem Valve™ silicone tubing (link opens pdf data sheet) is Platinum cured which significantly reduces the possibility of film build-up.

2.         The tubing is subjected to a very hard squeeze when the valve is closed. This squeeze is particularly effective in removing any film build-up

3.         If the tubing does become blocked – it can quickly and easily be replaced without having to remove the valve from service.

Read more about Bio-Chem Fluidics Pinch Valves here…

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Electric Rotary Valve Applications

Posted on September 21, 2011 by JohnT

Bio-Chem Fluidics Electric Rotary Valves are typically used in one of two main applications; port selection applications where one stream is diverted to one of either 4 or 6 different places, and loop injection applications where the valve can be used to load and inject fluids into a sample loop in two discrete steps.

Port selection
rotary valveBio-Chem Fluidics 4-way and 6-way selection / distribution valves allow for accurate and repeatable flow re-direction. One input can be diverted to any one of 6* outlets, or, 6* separate inputs can be diverted to one common outlet. (*Note: 4-way valves have 4 possible outlets / inputs).rotary valve

 

 

 

 

 

Loop injection

Bio-Chem Fluidics 4 port and 6 port switching valves are commonly used as sample injection devices for chromatography systems. This application is comprised of two distinct operations:  Load and Inject.

loop injection loadStep 1 – the sample can be loaded into the sample loop while the mobile phase is pumped directly through to the column.

 

 

 

loop injection injectStep 2 – when the valve switches to the inject position, the pump connects to the sample loop and the sample is carried onto and through the column. The “sample in” and “waste” ports are joined but are isolated from the loop.

 

 

Refer to Electric Rotary Valve page at our main site for more details. Download the full brochure here.

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The wait is over… Electric Rotary Valves Released!

Posted on June 29, 2011 by JWade

Earlier today, we flipped the switches on part of our Electric Rotary Valve section.  The 4 and 5 port valves are now fully released and ready to order!  The 6 and 7 port valves are going to take another month or so, but let’s not let that dampen our spirits.  The ERVs successfully completed life testing with results that exceeded our design requirements.  For full specifications on the product line, please check our updated brochure.  If you need even more detail, check out the extensive specifications in the ERV User Manual.

Our Electric Rotary Valves are available in 3 assembly levels:

  1. RV-E Series — Valve Head Only
  2. RV-SN Series — Valve w/ Motor
  3. RV-SC Series — Valve w/ Motor & Controller

We released 3 flow configurations in each assembly level:

  1. 4-port Switching
  2. 4-way Selection / Distribution
  3. 4-way Combination

Now that you know what we are selling, why would you want to buy it?  As with all of our products, our ERVs are aimed at a pretty particular market niche.  We’re aiming for low pressure applications (<500 PSI) requiring a highly inert fluid path.  Examples include flash chromatography, gel permeation chromatography, peptide synthesis and genome sequencing.  We’re also particularly targeted at OEM instruments.  You can use one of our ERVs on a benchtop but you’re going to have to make your own case and control system.

We are dedicated to OEM system support.  We’ve taken that to a new level with our rotary valves by offering them with and without the actuation method (a NEMA 17 stepper motor).  You can get a valve complete with the valve head, motor and control board or a stripped down version with just the valve head.  We’ve sourced a top quality Trinamic stepper motor, but we realize many of our customers have their own stepper motor suppliers.  We wanted to let you take advantage of your existing vendor base and in-house knowledge and just make use of the particular skills that we bring to the table.  Namely, precision fluid handling through highly inert materials.  The brochure and User Manual provide all the details needed to incorporate a stepper motor and controller of your choice.

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What’s Next?

Posted on June 20, 2011 by JWade

Our customers are high tech, innovative companies frequently at the leading edge of analytical or clinical technology.  That means they never stop moving and neither do we.  The first few posts in this blog covered 25 years of scientific innovation in just a few iconic applications.  We’ve worked on thousands of custom projects over those years.  In the next 25 years, we’ll work on many thousands more.  In each project, we’ll begin by listening to our customers.  We can deliver high quality, state-of-the-art fluid handling components for OEM systems. We cannot tell you what great new ideas the scientific community will come up with.  So, the question is posed to you – what’s next?

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