NRSTM Needle Control Valves
Models 8503 and 8504
Data Sheet
DS-VA-8503-eng
March, 2008
• Smooth non-reversing flow characteristics
• Constant flow at any given stem position
• Fifteen turns full open to full close provides
high turn to lift ratio for excellent resolution
• Six interchangeable needle tapers, each
increases capacity by an approximate factor
of three
• Bubble tight O-ring seal cannot be damaged
by overtightening
• Panel mounting nuts included - standard
• The NRS
valve cartridge is available on the
Brooks Sho-Rate® "50" flowmeters (see DSVA-
1350E-eng, DS-VA-K1350-55-eng)
• 1/8" NPT connections integrally machined into
body
• Optional numerical handle available for precise
valve positioning
DESCRIPTION
The Brooks® NRS (non-rising stem) control
valves are
designed specifically for extremely low flow gas and
liquid applications. Straight and 90° angle pattern models
in brass or stainless steel are available. They feature a
means of adjusting a sliding tapered needle which
prevents sticking due to foreign matter in the fluid.
These
valves are particularly suitable for precise control
requirements and possess a high turns to lift ratio. The
flow is constant for any given stem position.
Six needles with different tapers provide a wide choice
of flow ranges. Needles and orifices can be changed
without removing the
valve body from the line (two
different orifices are used, one for needle sizes 1-3,
another for sizes 4-6). An optional numerical handle
provides precise
valve settings of this high resolution
valve.
Model 8504
Straight Pattern
Needle Valve
Model 8513 Angle Pattern
Needle Valve with
Numerical Handle
SPECIFICATIONS
Capacities and Pressure Drops
Maximum Capacity
Needle Orifice (Std. cc/min.)
Taper No. Type Helium Air Water
1 300 150 4
2 Small 700 350 10
3 (0.041") 1,400 600 20
4 6,000 2,400 80
5 Larger 18,000 6,800 200
6 (0.093") 55,000 22,000 650
Capacities measured with 10 psig supply and an atmospheric
pressure exhaust. Flow capacities will vary for different gases,
liquids and pressures. Consult factory for further information.
Maximum Operating Pressure
Brass Model: 600 psig
Stainless Steel Model: 1000 psig
Maximum Operating Temperature
Brass Model: 180°F
Stainless Steel Model: 250°F
