3821-3831-3832K-3831K

Summary

Product Identification

This document describes the CAT PUMPS 38 Frame Block-Style Stainless Steel Plunger Pumps, available in standard and flushed configurations.

• Standard Models: 3821, 3831
• Flushed Models (K Models): 3821K, 3831K

Operating Limits

• Maximum Liquid Temperature: 160°F (71°C)
  • Note: For temperatures above 130°F, consult CAT PUMPS for specific inlet conditions and elastomer recommendations.

Feed Water

• Inlet Pressure: Flooded to 70 PSI (Flooded to 4.9 BAR)
• K Models: Feature a Special Flushed Inlet Manifold that allows external flushing for enhanced cooling with high-temperature liquids and improved lubrication with low-lubricity liquids.

Mechanical / Hydraulic

Model-Specific Specifications

• MODEL 3821, 3821K
  • Flow: 23 GPM (87 L/M)
  • Pressure Range: 100 to 2000 PSI (7 to 140 BAR)
  • Bore: 1.260" (32 mm)
• MODEL 3831, 3831K
  • Flow: 36 GPM (136 L/M)
  • Pressure Range: 100 to 1200 PSI (7 to 85 BAR)
  • Bore: 1.575" (40 mm)

Common Specifications

• RPM: 800 RPM
• Stroke: 1.890" (48 mm)
• Crankcase Capacity: 4.2 Qts. (4 L)
• Inlet Ports (2): 1-1/2" NPTF
• Flushing Ports (2): 1/2" NPTF (applicable to K Models)
• Discharge Ports (2): 1" NPTF
• Pulley Mounting: Either Side
• Shaft Diameter: 1.378" (35 mm)
• Weight: 167 lbs. (75 kg)
• Dimensions: 24.4 x 18.11 x 9.37" (620 x 460 x 238 mm)

Materials of Construction

• Valves: Precision design 316 stainless steel, hardened and polished.
• Manifolds: 316 SSL block-style for strength and corrosion resistance.
• Plungers: Special concentric, high-density, polished, solid ceramic.
• V-Packings: Specially formulated, CAT PUMP exclusive.
• Crankcase: Die cast aluminum (Optional Cast Iron crankcase available for hazardous environments).
• Crankshaft: Chrome-moly.
• Crankshaft Bearings: Oversized for longer life.

Electrical

Electric horsepower requirements vary by model, flow, and pressure. The official PDF contains a detailed table showing HP requirements at 800 RPM for various pressures (e.g., 100 PSI to 2000 PSI or 7 BAR to 140 BAR) and flows (e.g., 18 GPM to 36 GPM or 68 L/M to 136 L/M) depending on the specific model. Formulas for determining pump RPM, required HP, and motor pulley size are also provided.

Features

• Superior Design: Triplex plunger design ensures smoother liquid flow. An oil bath crankcase provides optimum lubrication. Close tolerance concentricity of the ceramic plunger maximizes seal life.
• K Models: Special Flushed Inlet Manifold permits external flush for added cooling with high-temperature liquids and lubrication with low-lubricity liquids.
• Easy Maintenance: The wet-end can be serviced easily without entering the crankcase. Inlet and discharge valve assemblies are interchangeable for simpler maintenance. Preset packings eliminate the need for packing gland adjustment, reducing maintenance costs.

Parts List and Exploded View

A comprehensive parts list, including part numbers, descriptions, quantities, and material codes (e.g., STL, AL, FPM, NBR, SS), is available in the official PDF, along with an exploded view diagram for all models.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions present in the complete OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used on the project.

Official datasheet (PDF)

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