281.491.2331 13839 West Bellfort Street Sugar Land, TX
281.491.2331 13839 West Bellfort Street Sugar Land, TX
ISO 9001:2015
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Since 1954
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inFlow™ (Fixed) Crude Oil Sampler

WELKER > Crude Oil Sampling > Crude Oil Composite Samplers > inFlow™ (Fixed) Crude Oil Sampler

Down to Size

Because a quality sample counts no matter the size of your line, we’ve scaled the top features of our inFlow™ Crude Oil Sampler to fit 2”–4” pipelines. Direct-mount or with a pipe spool, the fixed insertion length of the inFlow™ reaches the center one-third to collect isokinetic samples of condensate, crude oil, or other liquid hydrocarbons. Sized for bypass sampling or small main lines, the inFlow™ is also well-suited for use downstream of separators and on Lease Automatic Custody Transfer (LACT) Units for truck and rail car loading and unloading.

inFlow Fixed Crude Oil Sampler
API Chapter 8.2
ASTM D4177
ISO 3171
Power Up

Double-Acting Piston Motor

The inFlow™ is a reciprocating positive displacement probe sampler. The pumping power of the piston motor is enough to overcome the reliefs to push the full sample volume through to the container every time. High-viscosity products won’t get left behind—the pneumatic or hydraulic pressure on the piston generates enough force to sample thick oils. This double-acting pump is capable of collecting up to 15 grabs per minute for a more representative composite sample.

inFlow Insertion
Make Of It What You Will

Tailor to your Needs

Low pressure or high? NPT or flanged? With pipeline spool or without? Collection cup or piston-style collection head? Fixed or adjustable sample volume? Customize the inFlow™ with our variety of standard options and meet your process requirements without losing sampler or sample quality.

Insertion Shaft Feature & Option

Clearing the Way

Contamination Prevention

Plug & Purge

A complete composite sample is key to sample representativeness and cross-contamination prevention. This has influenced the design of our inFlow™ from the start. The inFlow™ comes standard with a Welker Volume Eliminator, which reduces excess volume inside the insertion shaft. The smaller internal volume minimizes sample retention, keeping residual sample at a minimum.

If you want to meet the latest recommendation of API 8.2 and ASTM D4177, swap the Volume Eliminator for a Welker Purge Tube. This change allows you to purge trapped liquid product from the collection head to the sample container. Be assured your composite sample is representative of the entire batch and that no samples remain to contaminate subsequent batches. Achieve a proper purge and automate the purge process with a Welker Plug & Purge™ Automatic Purging System.

Vanishing Act

Unique Collection Head

Vanishing Chamber™

0.22 cc, 0.5 cc, 1.0 cc, or 1.5 cc

Capture set volumes of sample with the Vanishing Chamber™ collection cup. Each actuation of the sample pump voids the collection cup, fully displacing the sample into the connected sample container.

Different Strokes

Piston-Style Collection Heads

B-Style Collection Head

0.5 cc, 1.0 cc, 1.5 cc, 2.0 cc

Does your application involve extreme temperatures, high pressures, or chemical contaminants? The B-Style collection head is up to the challenge! Even under such harsh conditions, this piston-style collection head fully displaces fixed volumes of sample into the connected sample container.

D-Style Collection Head

0–2 cc, 0–5 cc, 3–7 cc, or 5–12 cc

Take your pick: The D-Head offers four adjustable sample volume ranges so you can select the best fit for your application. With the two larger ranges of sample volumes, the sampler does not have to be operated as fast as similar samplers, which in turn prevents wear and tear. Use the Welker Checkpoint™ Sample Bite Verification Panel to confirm your collection head setting and actual grab volume.

Point of No Return

Backflow Protection

A companion to the collection head, the inline relief protects sample representativeness during fluctuations in pipeline pressure. Acting as a check valve, the inline relief keeps your samples in the sample container. If pipeline pressure drops, rest assured sample won’t flow from your container back to the pipeline. With the optional sand reliefs, you can sample product containing basic sediment and water (BS&W) without putting extra wear and tear on your sampler.


inFlow (Fixed) Crude Oil Sampler
Materials of Construction316/316L Stainless Steel Wetted Parts, Carbon Steel Motor and Base, PTFE, Buna Non-Wetted Seals, and Viton® Wetted Seals
Others Available
Pipeline Connection NPT
1 1/4"
Size: 2" (Standard), 3", 4"
Rating: 150, 300, or 600 ANSI RF
Sample Outlet Connection1/4" FNPT
Motor Housing¼" FNPT (Standard)
Insertion Length4 1/2" (Without Shaft Extension) (Standard)
6 1/4" (With Shaft Extension) (Standard)
Others Available
Utility RequirementsHydraulic or Pneumatic Supply for Motor Operation: 50 psig

Inert Gas Supply for Purge Operation: ¼" FNPT Connection (Optional)
Pneumatic ConsumptionAir: 0.095 scf/Stroke @ 50 psig
Natural Gas (With 0.6 Specific Gravity): 0.123 scf/Stroke @ 50 psig
Nitrogen: 0.097 scf/Stroke @ 50 psig
Sample VolumeB-Style Collection Head: 0.5 cc, 1.0 cc (Standard), 1.5 cc, or 2.0 cc
D-Style Collection Head (Long Motor): 3–7 cc (1/2" piston) or 5–12 cc (3/4" piston)
D-Style Collection Head (Short Motor): 0–2 cc (1/2" piston) or 0–5 cc (3/4" piston)
Vanishing Chamber Collection Cup: 0.22 cc, 0.5 cc, 1.0 cc, 1.5 cc
Operating Pressure 150 ANSI Carbon Steel: 285 psig @ -20 °F to 100 °F
300 ANSI Carbon Steel: 740 psig @ -20 °F to 100 °F
600 ANSI Carbon Steel: 1480 psig @ -20 °F to 100 °F
1¼" and 2" MNPT: 2220 psig @ -20 °F to 120 °F
Others Available
FeaturesExternal Adjustable Relief
Internal Relief
Welker Volume Eliminator
OptionsExternal Sand Relief
Pipeline Spool (With or Without Mixer)
Purge Tube
CE Compliance
NACE Compliance