Watertight Enclosure Documentation



Introduction

Blue Robotics offers a series of watertight enclosures for use on ROVs, AUVs, and other marine vehicles. A modular design consisting of a tube, sealing flanges, and various end caps allows lots of flexibility and modification. The enclosures are made of high-quality, precision machined parts and are simple to assemble.

Important Notes

Always inspect the O-rings before operation in water and especially when replacing the end-caps, aluminum flanges, or penetrators. Any dust, hair, or other particles can cause a leak.

Use plastic tools, NOT steel or other hard tools, to remove the O-rings from the aluminum sealing flange. Hard tools can create scrapes that will compromise sealing ability.

Specifications: (2” Series)

Specification Table (2” Series)

2” Series Enclosure    
Maximum Depth Rating 330 ft 100 m
Maximum Tested Depth (to failure) 660 ft 200 m
Failure Depth (for 12” length) 660 ft 200 m
Maximum External Pressure Rating 146 psi 1000 kPa
Weight in Air (12” Length) 1.1 lb 500 g
Weight in Water (Freshwater) -0.72 lb -326 g
Displacement 50.3 in^3 825 cm^3
Tube Inner Diameter 2 in 50.8 mm
Tube Outer Diameter 2.25 in 57.2 mm
Tube Thickness 0.125 in 3.2 mm
End Cap Thickness 0.24 in 6.0 mm
Aluminum Flange Inner Diameter 1.5 in 38 mm
Total Length 12.7 in 322 mm
Radial Seal O-ring (2 used) AS568-133, Buna-N  
Face Seal O-ring (1 used) AS568-030, Buna-N  
End Cap Screws M2x10 (Stainless Steel 316)  
Inner Mounting Holes M3 threading  

2D Drawings (2” Series)

2” Series Enclosure  
Assembly WTE2-ASM-R1 Drawing
Aluminum O-ring Flange WTE2-M-FLANGE-SEAL-R2 Drawing
Plain Solid End Cap WTE2-P-END-CAP-R1 Drawing
End Cap with 2 x 10mm Holes WTE2-P-END-CAP-2X10MM-R1 Drawing

3D Models (2” Series)

All 3D models are provided in zip archives containing the follow file types:

  • SolidWorks Part (.sldprt)
  • IGES (.igs)
  • STEP (.step)
  • STL (.stl)
2” Series Enclosure  
Assembly Model WTE2-ASM-R1.zip
Tube (Standard 11.75”, 298mm length) WTE2-P-TUBE-12-R1.zip
Aluminum O-ring Flange WTE2-M-FLANGE-SEAL-R2.zip
Plain Solid End Cap WTE2-P-END-CAP-R1.zip
End Cap with 2 x 10mm Holes WTE2-P-END-CAP-2X10MM-R1.zip

Specifications: 3” Series

Specification Table (3” Series)

3” Series Enclosure    
Maximum Depth Rating (Acrylic Tube) 500 ft 150 m
Maximum Depth Rating (Aluminum Tube) 1640 ft 500 m
Maximum Tested Depth (Acrylic Tube) 660 ft 200 m
Maximum Tested Depth (Aluminum Tube) 2460 ft 750 m
Failure Depth TBD  
Maximum External Pressure Rating 215 psi 1500 kPa
Tube Inner Diameter 3 in 76.2 mm
Tube Outer Diameter 3.5 in 88.9 mm
Tube Thickness 0.25 in 6.3 mm
End Cap Thickness 0.47 in 12.0 mm
Aluminum Flange Inner Diameter 3.5 in 89 mm
Total Length 12.93 in 329 mm
Radial Seal O-ring (2 used) AS568-230, Buna-N  
Face Seal O-ring (1 used) AS568-148, Buna-N  
End Cap Screws M3x12 (Stainless Steel 316)  
Inner Mounting Holes M3 threading  

2D Drawings (3” Series)

3” Series Enclosure  
Assembly Model WTE3-ASM-R1 Drawing
Aluminum O-ring Flange WTE3-M-FLANGE-SEAL-R2 Drawing
Plain Solid End Cap WTE3-P-END-CAP-R1 Drawing
End Cap with 4 x 10mm Holes WTE3-P-END-CAP-4X10MM-R1 Drawing
End Cap with 7 x 10mm Holes WTE3-P-END-CAP-7X10MM-R1 Drawing
Clamp WTE3-M-CLAMP-R1 Drawing
Aluminum Tube WTE3-M-TUBE-8P75-R1 Drawing

3D Models (3” Series)

All 3D models are provided in zip archives containing the follow file types:

  • SolidWorks Part (.sldprt)
  • IGES (.igs)
  • STEP (.step)
  • STL (.stl)
3” Series Enclosure  
Assembly Model WTE3-ASM-R1.zip
Acrylic Tube (Standard 11.75”, 298mm length) WTE3-P-TUBE-R1.zip
Aluminum Tube (Standard 8.75”, 222mm length) WTE3-M-TUBE-8P75-R1.zip
Aluminum O-ring Flange WTE3-M-FLANGE-SEAL-R1.zip
Plain Solid End Cap WTE3-P-END-CAP-R1.zip
End Cap with 4 x 10mm Holes WTE3-P-END-CAP-4X10MM-R1.zip
End Cap with 7 x 10mm Holes WTE3-P-END-CAP-7X10MM-R1.zip
Clamp WTE4-M-CLAMP-R1.zip

Specifications: 4” Series

Specification Table (4” Series)

4” Series Enclosure    
Maximum Depth Rating (Acrylic Tube) 330 ft 100 m
Maximum Depth Rating (Aluminum Tube) 1300 ft 400 m
Maxium Tested Depth (Acrylic Tube) 500 ft 150 m
Maxium Tested Depth (Aluminum Tube) 2000 ft 610 m
Maximum Pressure 146 psi 1000 kPa
Tube Inner Diameter 4 in 101.6 mm
Tube Outer Diameter 4.5 in 114.3 mm
Tube Thickness 0.25 in 6.3 mm
End Cap Thickness 0.47 in 12.0 mm
Aluminum Flange Inner Diameter 3.5 in 89 mm
Total Length 13.15 in 334 mm
Radial Seal O-ring (2 used) AS568-238, Buna-N  
Face Seal O-ring (1 used) AS568-154, Buna-N  
End Cap Screws (Acrylic Endcaps) M3x16 (Stainless Steel 316)  
End Cap Screws (Aluminum & Dome Endcaps) M3x12 (Stainless Steel 316)  
Inner Mounting Holes M3 threading  

2D Drawings (4” Series)

4” Series Enclosure  
Assembly Model WTE4-ASM-R1 Drawing
Aluminum O-ring Flange WTE4-M-FLANGE-SEAL-R2 Drawing
Plain Solid End Cap WTE4-P-END-CAP-R1 Drawing
Aluminum Solid End Cap WTE4-M-END-CAP-R1 Drawing
Aluminum End Cap with 10 x 10mm Holes WTE4-M-END-CAP-10X10MM-R1 Drawing
End Cap with 5 x 10mm Holes WTE4-P-END-CAP-5X10MM-R1 Drawing
End Cap with 10 x 10mm Holes WTE4-P-END-CAP-10X10MM-R1 Drawing
End Cap with 14 x 10mm Holes WTE4-M-END-CAP-14X10MM-R1 Drawing
Dome End Cap WTE4-P-DOME-R2 Drawing
Clamp WTE4-M-CLAMP-R1 Drawing
Aluminum Tube WTE4-M-TUBE-12-R1 Drawing

3D Models (4” Series)

All 3D models are provided in zip archives containing the follow file types:

  • SolidWorks Part (.sldprt)
  • IGES (.igs)
  • STEP (.step)
  • STL (.stl)
4” Series Enclosure  
Assembly Model WTE4-ASM-R2.zip
Acrylic Tube (Standard 11.75”, 298mm length) WTE4-P-TUBE-12-R1.zip
Aluminum Tube (Standard 11.75”, 298 mm length) WTE4-M-TUBE-12-R1.zip
Aluminum O-ring Flange WTE4-M-FLANGE-SEAL-R2.zip
Plain Solid End Cap WTE4-P-END-CAP-R1.zip
Aluminum Solid End Cap WTE4-M-END-CAP-R1.zip
Aluminum End Cap with 10 x 10mm Holes WTE4-M-END-CAP-10X10MM-R1.zip
End Cap with 5 x 10mm Holes WTE4-P-END-CAP-5X10MM-R1.zip
End Cap with 10 x 10mm Holes WTE4-P-END-CAP-10X10MM-R1.zip
End Cap with 14 x 10mm Holes WTE4-M-END-CAP-14X10MM-R1.zip
Dome End Cap WTE4-P-DOME-R1.zip
Clamp WTE4-M-CLAMP-R1.zip


Assembly

The assembly process is simple and straightforward - it will take a few minutes!

Tools Needed:

  • Silicone grease
  • 2.5mm Hex Driver
  • Isopropyl alcohol

Video Tutorial


Steps

  1. We recommend first cleaning the O-rings and the O-ring grooves with isopropyl alcohol. This will ensure a good seal. Next, lubricate the three O-rings with a thin layer of silicone grease and then install the two thick O-rings into the grooves on the flange. The thin O-ring is placed in the groove in the face of the flange.

  1. Attach the end-caps to the flanges with 6 socket cap screws. Gently tighten the screws in an alternating cross pattern so that the O-ring is compressed but not so tight as to damage the plastic. Do not overtighten the screws!

  1. Install the vent and any necessary cable penetrators into the end-cap.
  2. Install the flanges onto the tube and replace the vent cap to seal.

Opening Enclosure

Opening the enclosure is straightforward.

Steps:

  1. Remove the vent plug.

  1. Remove the flange using the tabs on the sides of the end cap.

Making Custom End Caps

One of the cool things about the watertight enclosure design is that it’s compatible with all sort of end cap sizes and shapes. We’ve got a few different ones available but we encourage you to design your own to perfectly suit your application.

The CAD files above as well as the DXF drawing file attached below will give you a good starting point for your design. You’ll need access to either 3D modeling software like SolidWorks or AutoCAD or 2D drawing software like Adobe Illustrator, Inkscape, and others.

Here are a few things to remember:

  • We recommend the following thicknesses of cast acrylic to handle the pressure:
    • 2” Series: 6mm / 0.25”
    • 3” Series: 9mm / 0.375”
    • 4” Series: 12mm / 0.50”
  • Note the inner diameter of the aluminum sealing flange and ensure that any holes are within that diameter
  • Feel free to extend beyond the original shape to add mounting holes, etc.

Once you have a design, you can cut the parts yourself if you have a laser cutter or use an online service. We have frequently used Pololu Laser Cutting with great results!