Marquest Scientific, Inc.
Marquest Scientific, Inc.
2950 Airway Avenue, Bldg C-5
Costa Mesa, California U.S.A.
Tel: (714) 491-9191
Toll Free: (866) 452-2349
Fax: (714) 491-9199
Email: sales@marquestscientific.com
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The L Series "Life Series" needle valve is uniquely engineered with a virgin PTFE (Teflon) tip designed specifically for high-frequency on/off cycling—ideal for applications where the valve is opened and closed daily throughout the product's lifecycle. Unlike traditional needle valves, which are typically set once and left in position, the L Series is built for repetitive actuation without wear or galling, offering exceptional low-torque operation, long-term bubble-tight sealing, and easy field maintenance—making it the preferred choice for demanding, high-cycling environments.

Overview
The ultimate in on/off product cycle life, our "Life Series" needle valves comprise a Virgin PTFE tipped needle for exceptionally low torque, long life on/off operation. In applications where the end user needs to operate a needle valve from open to closed position on a high frequency basis, the "Life Series" provides all the inherent benefits of a Needle Valve while providing a longer service life compared to rigid hard seated needle valves where galling can occur from high frequency on/off operation. 
 
Features:

PTFE On/Off seal is easily replaced in the field, no tools required
Exceptional Low Torque on/off operation
Needle finish, SPI/SPE No. 1. Bubble tight, low torque shutoff long term performance.
All injection molded, rugged design and construction
24 Pitch metering thread. 20% Finer metering control. Excellent Linearity of Flow.
Needle Stem is PTFE sealed for excellent chemical resistance & high purity.
Integrally designed panel mounting, no fasteners required, mounts to panel thicknesses from 1/16" to 1/2".
No elastomers (O-Rings), metals or lubricants, no corrosion, no contamination.

End connections:
1/4", 3/8", 1/2" Female NPT, Solvent Socket "Slip". Tube Connections Available Click Here. 
 
Max Pressure Ratings:
PVC: 180 PSI @ 72° Fahrenheit
CPVC: 200 PSI @ 72° Fahrenheit
Polypropylene: 150 PSI @ 72° Fahrenheit
PVDF: 220 PSI @ 72° Fahrenheit
 
Materials of Construction:
Valve Body & Components: Injection molded in PVC, Glass & Mineral Reinforced Polypropylene, CPVC, & High Purity PVDF. FDA, USDA, and USP standards are either met and/or exceeded, please contact us for further validation. 
Stem Seal & Integral Needle Tip: The stem seal and needle tip seal are machined from 100% Virgin PTFE (Polytetrafluoroethylene).
 
 

 

PLEASE CLICK ITEM # BELOW TO VIEW ADDITIONAL SPECIFICATIONS & DOWNLOADS
NGL-OVERVIEW-SQUARE.jpg
Unit of Measure
1 2 

Item #

Materials

Inlet x Outlet

Style

Seal

Cv Factor

List Price

NGL-250-PVC N/A PVC N/A 1/4" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $88.95
NGL-375-PVC N/A PVC N/A 3/8" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $88.95
NGL-500-PVC N/A PVC N/A 1/2" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.620 $94.95
NAL-250-PVC N/A PVC N/A 1/4" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $88.95
NAL-375-PVC N/A PVC N/A 3/8" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $88.95
NAL-500-PVC N/A PVC N/A 1/2" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.780 $94.95
NGL-250-CPV N/A CPVC N/A 1/4" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $94.95
NGL-375-CPV N/A CPVC N/A 3/8" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $94.95
NGL-500-CPV N/A CPVC N/A 1/2" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.620 $97.95
NAL-250-CPV N/A CPVC N/A 1/4" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $94.95
NAL-375-CPV N/A CPVC N/A 3/8" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $94.95
NAL-500-CPV N/A CPVC N/A 1/2" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.780 $97.95
NGL-250-PPR N/A Polypro N/A 1/4" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $90.95
NGL-375-PPR N/A Polypro N/A 3/8" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $90.95
NGL-500-PPR N/A Polypro N/A 1/2" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.620 $95.50
NAL-250-PPR N/A Polypro N/A 1/4" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $90.95
NAL-375-PPR N/A Polypro N/A 3/8" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $90.95
NAL-500-PPR N/A Polypro N/A 1/2" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.780 $95.50
NAL-250-PVD N/A PVDF N/A 1/4" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $174.50
NGL-250-PVD N/A PVDF N/A 1/4" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $174.50
NAL-375-PVD N/A PVDF N/A 3/8" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $174.50
NGL-375-PVD N/A PVDF N/A 3/8" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.310 $174.50
NAL-500-PVD N/A PVDF N/A 1/2" Female NPT N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.780 $174.50
NGL-500-PVD N/A PVDF N/A 1/2" Female NPT N/A Globe Pattern, L Series Needle N/A PTFE N/A 0.620 $174.50
NAL-250S-PVC N/A PVC N/A 1/4" Female Solvent Socket N/A Angle Pattern, L Series Needle N/A PTFE N/A 0.426 $88.95
Unit of Measure
1 2