Departments› Chemical Engineering› Module IV› Engineering Drawing And Design› Ch 6: Produce solid geometry drawings
Chemical Engineering  ·  Level 6
Engineering Drawing And Design
Chapter 6: Produce solid geometry drawings
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Chemical engineers in Kenya operate in a dynamic environment where the design and visualization of complex equipment and plant layouts are crucial. Proficiency in producing solid geometry drawings facilitates communication between design, manufacturing, and maintenance teams. This chapter focuses on sketching, creating pictorial drawings, developing patterns, and using AutoCAD for solid geometry drawings, all tailored to chemical engineering applications such as reactors, heat exchangers, and piping components.

6.1 Sketching · Pictorial drawings · Patterns · Solid geometry drawings using AutoCAD

6.1.1 Sketching in Chemical Engineering Design

Sketching is the foundational skill for chemical engineers when conceptualizing equipment or plant layouts quickly. It allows engineers to express ideas, troubleshoot problems, and communicate initial designs before formal CAD work. In Kenya, sketching is essential during site visits or feasibility studies where digital tools may not be immediately accessible.

Purpose of Sketching in Chemical Engineering

  • Idea Generation: Sketching helps visualize complex chemical plant components such as distillation columns or pumps rapidly.
  • Problem Solving: Engineers use sketches to identify design flaws on-site, such as pipe routing conflicts or equipment placement.
  • Communication: Sketches serve as a universal language among multidisciplinary teams, including process engineers, fabricators, and maintenance staff.
  • Documentation: Quick sketches can record observations during inspections or audits for later reference.
  • Preliminary Design: Before committing to detailed drawings, sketching enables conceptual exploration of design alternatives.

Techniques for Effective Sketching

  • Use of Basic Shapes: Circles, rectangles, and cylinders form the basis for representing tanks, pipes, and vessels.
  • Proportionality: Maintaining relative sizes helps in understanding spatial relationships.
  • Annotations: Clear labels and notes provide context, such as material specifications or flow directions.
  • Perspective Views: Employing isometric or oblique sketches to represent 3D objects on 2D paper.
  • Neatness and Clarity: Ensures that sketches are understandable to others without ambiguity.

Tools for Sketching

  • Drawing Boards: Provide a flat surface for accurate hand sketches.
  • Pencils and Erasers: Allow corrections and adjustments.
  • Scale Rulers: Aid in maintaining proportions.
  • Templates: For standard symbols like valves and pumps.
  • Graph Paper: Helps maintain alignment and scale.

Challenges in Sketching and How to Overcome Them

Challenges
  • Lack of Precision: Hand sketches may lack dimensional accuracy needed for fabrication.
  • Interpretation Variability: Different viewers may interpret sketches differently.
  • Time Constraints: Quick sketches may omit critical details.
  • Limited Revision Options: Corrections can be cumbersome on paper.
  • Dependence on Skill: Quality depends heavily on the engineer’s drawing ability.
Solutions
  • Use Sketching as a Preliminary Step: Follow up with CAD drawings for precision.
  • Standardize Symbols and Notations: To reduce misinterpretation.
  • Training: Regular practice to improve sketching skills.
  • Digital Sketching Tools: Tablets with styluses can combine flexibility with accuracy.
  • Clear Annotations: Provide detailed notes to supplement sketches.

6.1.2 Pictorial Drawings for Chemical Engineering Components

Pictorial drawings are three-dimensional representations of objects on two-dimensional media, providing a realistic view of equipment. Kenyan chemical engineers use pictorials to help stakeholders visualize complex machinery such as reactors or pumps before construction or installation.

Types of Pictorial Drawings

  • Isometric Drawings: Show three faces of an object equally foreshortened, maintaining scale along each axis.
  • Oblique Drawings: Present the front face in true shape and size, with depth lines drawn at an angle.
  • Perspective Drawings: Mimic human eye perception with vanishing points, providing realistic depth.
  • Exploded Views: Separate components to show assembly relationships.
  • Axonometric Drawings: Similar to isometric but with unequal foreshortening along axes.

Importance of Pictorial Drawings

  • Improved Visualization: Helps non-technical stakeholders understand designs.
  • Assembly Guidance: Exploded views assist technicians during installation.
  • Design Verification: Enables cross-checking of component fit and interference.
  • Documentation: Serves as reference for maintenance and troubleshooting.
  • Marketing and Training: Used in manuals and presentations to explain equipment.

Conventions and Standards in Pictorial Drawings

  • Line Types: Use continuous thick lines for visible edges, dashed lines for hidden edges as per BS 8888.
  • Scale: Typically drawn at scales from 1:5 to 1:20 depending on object size.
  • Dimensioning: Dimensions are usually shown on orthographic projections, not pictorials.
  • Annotations: Include labels, part numbers, and material specifications.
  • Title Blocks: Must indicate drawing title-scale, date, and drafter’s name following ISO 7200.

Creating Pictorial Drawings: Stepwise Approach

  1. Select Drawing Type: Choose isometric, oblique, or perspective based on communication needs.
  2. Establish Reference Axes: Draw three axes for isometric or front face for oblique.
  3. Outline Main Shapes: Sketch basic geometric forms representing the component.
  4. Add Details: Include smaller features such as flanges, bolts, and nozzles.
  5. Apply Line Conventions: Differentiate visible and hidden edges.
  6. Label Components: Annotate for clarity.
  7. Review for Accuracy: Check proportions and conformity to standards.

6.1.3 Patterns in Chemical Engineering Design

Patterns are templates or guides used to shape materials into desired forms, essential in fabricating components like pipe bends, tank shells, and heat exchanger plates. Chemical engineers in Kenya often collaborate with fabricators using patterns to ensure accurate production.

Definition and Purpose of Patterns

  • Definition: A pattern is a physical or drawn outline that guides the shaping or cutting of material.
  • Purpose: To translate flat materials into three-dimensional shapes.
  • Use in Fabrication: Patterns ensure repeatability and accuracy in manufacturing.
  • Cost Efficiency: Reduce material wastage by guiding precise cuts.
  • Quality Control: Patterns help maintain dimensional consistency across batches.

Types of Patterns Used in Chemical Engineering

  • Flat Patterns: Used for sheet metal components such as ductwork and tank covers.
  • Developed Patterns: Created by unfolding 3D surfaces into 2D layouts.
  • Template Patterns: Physical cutouts used to mark materials.
  • CAD-Generated Patterns: Digital layouts produced by software for CNC cutting.
  • Modular Patterns: Designed for repeated use in batch fabrication.

Steps to Develop a Pattern

  1. Analyze the 3D Shape: Understand geometry and dimensions.
  2. Select Development Method: Choose between manual or CAD methods.
  3. Unfold Surfaces: Convert curved or angled surfaces into flat layouts.
  4. Draw Pattern on Material: Use templates or CAD output.
  5. Cut Material: Follow pattern outlines accurately.
  6. Assemble and Test Fit: Check conformity to intended shape.

Challenges in Pattern Development and Solutions

Challenges
  • Complex Geometry: Difficult to unfold irregular shapes.
  • Material Distortion: Stretching or compression during forming.
  • Measurement Errors: Lead to ill-fitting parts.
  • Fabrication Variability: Differences in material thickness or properties.
  • Communication Gaps: Between design and fabrication teams.
Solutions
  • Use CAD Software: For accurate pattern development.
  • Material Testing: Understand behavior before fabrication.
  • Precise Measurement Tools: Employ laser scanners or templates.
  • Regular Communication: Between engineers and fabricators.
  • Prototype Patterns: Test before full production.

6.1.4 Solid Geometry Drawings Using AutoCAD in Chemical Engineering

AutoCAD is a critical tool for chemical engineers in Kenya to produce precise solid geometry drawings of equipment such as reactors, pumps, and piping assemblies. These drawings support design validation, fabrication, and maintenance planning.

Name Specification Use
AutoCAD 3D modelling software, supports solid geometry, layering, and annotation Create detailed solid models and drawings of chemical plant components

  • Usage:

    • Import or create 3D models of equipment.
    • Use layers to separate components for clarity.
    • Apply standard line types and dimensioning.
    • Generate 2D views from 3D models for fabrication.
    • Export drawings in formats compatible with CNC machines.

  • Maintenance:

    • Regular updates to software.
    • Backup of drawing files.
    • Calibration of input devices like digitizers.
    • User training on new features.
    • Use of standardized templates and blocks.

Procedure for Creating Solid Geometry Drawings in AutoCAD

  1. Set Drawing Limits: Define the workspace size to match component dimensions.
  2. Draw Reference Axes: Use ISO long dash-short dash line type for axis lines.
  3. Create Basic Shapes: Use commands like BOX, CYLINDER, and SPHERE to form solids.
  4. Modify Solids: Apply operations such as UNION, SUBTRACT, and INTERSECT.
  5. Add Details: Use fillets, chamfers, and holes for realistic features.
  6. Apply Layers and Line Types: Organize components and apply standard line conventions.
  7. Generate 2D Projections: Extract views like front, top, and side.
  8. Dimension and Annotate: Add measurements and notes according to BS/ISO standards.
  9. Save and Export: Store drawings in DWG format and export to PDF or CNC-compatible files.

Standards and Conventions in AutoCAD Drawings

  • Line Types: Use ISO standard line types for visible, hidden, and center lines.
  • Scales: Draw at scales suitable for component size, typically 1:10 or 1:20.
  • Title Blocks: Include project details, client name, drawing number-scale, and drafter’s name.
  • Units: Use metric units (millimeters) consistently.
  • Layer Management: Separate mechanical, piping, and electrical components.

Example: Drawing a Solid Model of a Chemical Reactor

  • The reactor is a cylindrical vessel 1500 mm diameter and 3000 mm height.
  • Top flange with bolt holes spaced evenly around the circumference.
  • Nozzles placed at specified heights for inlet and outlet.
  • Support legs modeled as rectangular solids attached at base.
  • The completed drawing shows isometric and orthographic views with dimensions.

Practice Questions

  1. Sketch an isometric view of a heat exchanger with inlet and outlet nozzles positioned on the top and side (15 marks)
  2. Develop a flat pattern for a conical hopper used in a chemical plant, including all dimensions (15 marks)
  3. Using AutoCAD, create a solid model of a cylindrical storage tank with a manhole and two nozzles; provide front, top, and side views (20 marks)

Chapter Summary

This chapter introduced the fundamentals of sketching as the foundation for creating clear and accurate engineering drawings. It then explored the development of pictorial drawings, which provide three-dimensional representations to enhance understanding of complex objects. The discussion progressed to patterns, emphasizing their role in manufacturing and how they relate to solid geometry. The chapter concluded with detailed procedures for producing solid geometry drawings using AutoCAD, highlighting the importance of precision and adherence to drawing standards. Throughout, emphasis was placed on the step-by-step construction of drawings, the use of proper conventions, and the practical application of digital tools to improve accuracy and efficiency in engineering design.

Self-Assessment

🔒 PDFDownload this self-assessment, with answers

A. Written Assessment

  1. Which projection method is most commonly used for pictorial drawings in chemical plant layout design? (2 marks)
  2. List three key line types used in solid geometry drawings according to BS 8888 standards. (3 marks)
  3. Describe the main difference between an isometric sketch and a perspective sketch. (2 marks)
  4. What is the purpose of pattern development in chemical engineering equipment fabrication? (2 marks)
  5. Identify two advantages of using AutoCAD for solid geometry drawings in chemical plant design. (2 marks)
  6. Explain why scale selection is critical when producing drawings of chemical reactors. (3 marks)
  7. What is the standard angle used in isometric drawings for the horizontal axes? (1 mark)
  8. Name the type of solid geometry drawing that best represents the internal features of a chemical vessel. (2 marks)
  9. Describe the steps to create a simple cylindrical vessel drawing using AutoCAD. (4 marks)
  10. How does layering in AutoCAD improve the clarity of complex chemical plant drawings? (2 marks)
Show Answers
  1. Isometric projection is most commonly used because it allows clear visualization of three dimensions without distortion.
  2. Common line types include: continuous thick (visible edges), dashed (hidden edges), and chain thin (centre lines).
  3. An isometric sketch uses equal angles (120°) and scale on all axes, while a perspective sketch shows objects as they appear to the eye with vanishing points.
  4. Pattern development enables the creation of flat templates for cutting and forming sheet metal parts such as vessel shells and cones.
  5. Advantages include: precision and accuracy in dimensions and easy modification and layering for complex assemblies.
  6. Scale ensures the drawing is readable and fits on standard paper sizes while preserving proportion and detail necessary for fabrication.
  7. The standard angle for isometric drawings is 30 degrees from the horizontal for both left and right axes.
  8. A sectional drawing best represents internal features by cutting through the vessel to expose the interior.
  9. Steps:
    1) Draw the base circle using the circle tool.
    2) Extrude the circle to the desired height to form the cylinder.
    3) Add details such as flanges or nozzles using additional shapes.
    4) Apply layers and dimensioning for clarity.
  10. Layering allows separation of different components (e.g., piping, vessels, electrical) so they can be viewed or edited independently without clutter.

B. Oral Assessment

  1. Discuss how solid geometry drawings enhance communication between chemical engineers and fabricators during plant equipment construction.
  2. Explain the challenges and solutions when transitioning from hand sketches to AutoCAD solid geometry drawings in a chemical engineering design office.
Answer Guide

Question 1 key points:

  • Solid geometry drawings provide accurate spatial representation essential for fabrication.
  • They reduce misinterpretation by showing true dimensions and relationships between parts.
  • Facilitate cost estimation and material planning by visualizing the full assembly.

Question 2 key points:

  • Challenges include learning curve for software, maintaining drawing standards, and ensuring data integrity.
  • Solutions involve training programs, enforcing standard templates and layers, and regular quality audits of drawings.

C. Case Study

At the Athi River Chemicals Limited facility, a new pressure vessel is to be designed and fabricated for liquid storage.

Tasks:
a) Produce a detailed isometric sketch of the pressure vessel showing all major components and connections. (10 marks)
b) Using AutoCAD, develop a solid geometry drawing of the vessel with precise dimensions and standard line types. (15 marks)
c) Create a flat pattern layout for the vessel’s cylindrical shell section to guide sheet metal cutting. (10 marks)

Suggested Approach

a) Begin by sketching the vessel’s cylindrical body, domed ends, and nozzles in isometric view, ensuring correct proportions and angles (30° axes). Label all components clearly.
b) In AutoCAD, start with the base circle for the cylinder, extrude to height, and add domed ends using appropriate solid modeling commands. Apply BS 8888 line conventions and dimension the drawing comprehensively.
c) Unfold the cylindrical shell into a rectangular flat pattern considering allowances for welding and overlaps. Use AutoCAD’s pattern tools or manually develop the layout following pattern development principles for sheet metal.

Chapter Examination Questions

🔒 PDFDownload these examination questions, with worked answers

SECTION A (40 Marks) - Answer ALL Questions

  1. Define pictorial drawing and explain its importance in chemical plant layout design. (4 marks)
  2. List four common types of solid geometry drawings used in chemical engineering and provide one example application for each. (4 marks)
  3. Describe the main steps involved in sketching a 3D isometric view of a cylindrical chemical storage tank. (4 marks)
  4. Explain how pattern development is used in fabricating conical hoppers in chemical processing plants. (4 marks)
  5. Identify three key AutoCAD tools used to create solid geometry drawings for pipe fittings in chemical engineering. (4 marks)
  6. State the Kenyan Standard that governs line types and conventions for engineering drawings and summarize its relevance to chemical engineering drawings. (4 marks)
  7. Compare orthographic projection and pictorial drawing in terms of their use in chemical equipment design. (4 marks)
  8. What is the significance of scale selection when producing solid geometry drawings for chemical reactors? (4 marks)
  9. Outline the procedure for creating a solid model of a heat exchanger using AutoCAD. (4 marks)
  10. Explain the role of title blocks in solid geometry drawings submitted to chemical engineering project stakeholders. (4 marks)
Section A - Answers
  1. Pictorial drawing represents a three-dimensional object on a two-dimensional plane, showing length, width, and height in one view. It is important in chemical plant layout to visualize equipment and spatial relationships clearly.
  2. Common types: Isometric (e.g., pipe layout), Oblique (e.g., valve assembly), Perspective (e.g., plant overview), Orthographic (e.g., pump detail).
  3. Steps: Draw base ellipse for cylinder end, project vertical edges, draw top ellipse parallel to base, connect edges, add details like nozzles or supports.
  4. Pattern development involves unfolding the conical surface into a flat layout for cutting sheet metal accurately before rolling and welding into shape.
  5. AutoCAD tools: Extrude, Revolve, Union/Solid Editing tools, and ViewCube for 3D navigation.
  6. KS EAS 2:2009 (based on ISO 128) governs line types; it ensures uniformity and clarity in chemical engineering drawings for fabrication and inspection.
  7. Orthographic projection shows multiple 2D views for precise measurement; pictorial gives a 3D visual impression useful for presentations and conceptual design.
  8. Scale ensures drawings fit on standard sheets while preserving detail and proportion, critical for accurate fabrication of reactors.
  9. Procedure: Create 2D profile sketches of shell and tubes, use revolve and extrude commands, assemble components, apply materials and layers.
  10. Title blocks provide essential information such as drawing title-scale, author, date, and revision, ensuring traceability and communication among project teams.

SECTION B (60 Marks) - Answer any TWO Questions

Question 11 (Compulsory - 20 marks)
Kenya Pipeline Company plans to fabricate a new chemical dosing tank. You are tasked with preparing detailed solid geometry drawings.
a) Using AutoCAD, describe step-by-step how you would produce a 3D solid model of a cylindrical dosing tank with a conical bottom and manhole. Include considerations for layers and line types according to Kenyan standards. (10 marks)
b) Sketch freehand an isometric view of the dosing tank showing key features and label all parts clearly. Explain how this drawing aids the fabrication team. (10 marks)

Question 12 (20 marks)
Explain the process of developing a flat pattern from a conical hopper used in a chemical plant. Include the mathematical principles involved and how accuracy is ensured in the pattern before fabrication.

Question 13 (20 marks)
Discuss the advantages and limitations of using pictorial drawings versus solid geometry AutoCAD models in the design review meetings of a chemical processing facility. Support your answer with examples.

Question 14 (20 marks)
A chemical engineer is required to produce orthographic projections of a complex valve assembly. Outline the procedure for preparing these drawings manually and then using AutoCAD. Highlight the standards that must be followed to ensure the drawings meet Kenyan regulatory requirements.

Section B - Answers

Question 11
a) Start by drawing the base circle using the circle tool, then extrude it to form the cylinder height. Use the cone tool or revolve the conical bottom profile. Add the manhole using a cut/extrude command. Assign layers for base geometry, annotations, and hidden lines as per KS EAS 2:2009. Use continuous lines for visible edges, dashed for hidden edges. Set scale and dimension styles before finalizing.
b) The freehand isometric sketch shows the cylindrical body, conical bottom, manhole location, and support legs. Labels include dimensions and material notes. This drawing helps fabricators visualize assembly and identify critical features, reducing errors and fabrication time.

Question 12
Pattern development involves unrolling the conical surface into a flat shape. Using geometry, the slant height is calculated from the cone dimensions. The arc length corresponds to the circumference of the cone base. Accuracy is ensured by precise measurements and using templates or CAD software for pattern validation prior to cutting.

Question 13
Pictorial drawings provide intuitive visualization useful for client presentations and early design phases but lack precise dimensions. Solid geometry AutoCAD models allow detailed analysis, simulation, and fabrication data but require specialized skills and software. Combining both enhances communication and technical accuracy in design reviews.

Question 14
Manually, start by sketching front, top, and side views maintaining orthographic projection rules. Use standard line types and dimensioning per KS EAS 2:2009. In AutoCAD, create 2D sketches, use layers for clarity, and apply dimensioning tools. Follow line conventions, scales, and title block requirements to comply with Kenyan drawing standards and ensure regulatory acceptance.

References

  1. TVET CDACC - Engineering Drawing And Design Curriculum (Cycle 3, 2025)
  2. TVET CDACC - Engineering Drawing And Design Occupational Standards
  3. Kenya Bureau of Standards KS EAS 2:2009 - Technical Drawing - General Principles of Presentation
  4. Engineers Registration Act, 2011 (Cap 530) - Professional Practice Regulations

Chapter Practical Activities

Practical 1: Freehand Sketching of Chemical Equipment

Time: 2 Hours | Type: Individual

Resources Required:

  • A3 drawing sheets (5 sheets)
  • HB and 2B pencils
  • Eraser, ruler 300mm
  • Laptop with Windows 10 (for reference images)
  • PPE: None required

You are a trainee chemical engineer at Kenya Pipeline Company (KPC) in Mombasa tasked with producing freehand sketches of common chemical processing equipment used in the facility.

Tasks:
i. Sketch freehand the front view of a cylindrical storage tank with a conical roof.
ii. Sketch freehand the side view of a distillation column with external ladders.
iii. Sketch freehand the sectional view of a heat exchanger showing tube bundles.
iv. Label all major parts clearly on your sketches.

Assessor Observation Criteria:

  • [ ] Accuracy of proportions in sketches
  • [ ] Clarity and neatness of lines and labels
  • [ ] Completeness of views as instructed
  • [ ] Use of correct chemical engineering symbols and conventions

Practical 2: Constructing Isometric Pictorial Drawings of a Pump

Time: 3 Hours | Type: Individual

Resources Required:

  • Drawing board 600mm x 450mm
  • Mechanical pencils 0.5mm
  • Set squares and protractor
  • Scale ruler (metric)
  • A3 drawing sheets (3 sheets)
  • PPE: None required

At the Eldoret Water and Sanitation Company, you have been assigned to produce an isometric pictorial drawing of a centrifugal pump used in chemical dosing.

Tasks:
i. Draw the base outline of the pump in isometric projection.
ii. Construct the pump casing and impeller housing using standard isometric methods.
iii. Add inlet and outlet pipe connections in correct orientation.
iv. Dimension the drawing as per BS ISO 128 standards.

Assessor Observation Criteria:

  • [ ] Correct use of isometric angles and scale
  • [ ] Accuracy in representing pump components
  • [ ] Proper dimensioning and labeling
  • [ ] Neatness and line quality adhering to standards

Practical 3: Developing a Flat Pattern for a Conical Hopper

Time: 2.5 Hours | Type: Individual

Resources Required:

  • Drawing board
  • Compass (150mm radius)
  • Pencil HB and eraser
  • Ruler 300mm
  • Protractor
  • PPE: None required

You are working at a tea processing factory in Kericho and need to prepare a flat pattern for a conical hopper used in leaf collection.

Tasks:
i. Calculate the development parameters for a conical hopper with base diameter 600mm and height 450mm.
ii. Construct the flat pattern of the conical hopper on drawing sheet.
iii. Mark seam allowances and cutting lines.
iv. Label all dimensions and angles clearly.

Assessor Observation Criteria:

  • [ ] Correct calculation of slant height and sector angle
  • [ ] Accuracy of flat pattern layout
  • [ ] Clear marking of seam allowances
  • [ ] Proper labeling and dimensioning

Practical 4: Solid Geometry Drawing of a Spherical Vessel Using AutoCAD

Time: 3 Hours | Type: Individual

Resources Required:

  • Computer with AutoCAD 2023 installed
  • Mouse and keyboard
  • Sample technical specification sheet for a spherical vessel (provided)
  • PPE: None required

At the Kenya Petroleum Refineries Limited (KPRL) in Nairobi, you are tasked with creating a 3D solid model of a spherical storage vessel using AutoCAD.

Tasks:
i. Set up the drawing workspace with correct units and scale.
ii. Create a 3D solid sphere with diameter 1200mm.
iii. Add cylindrical nozzles on the sphere surface as per specification.
iv. Produce orthographic views (front, side, top) from the 3D model.

Assessor Observation Criteria:

  • [ ] Correct workspace setup and units
  • [ ] Accuracy of sphere dimensions and nozzle placement
  • [ ] Completeness of orthographic views generated
  • [ ] Proper layer management and line types used

Practical 5: Sketching and Dimensioning an Industrial Valve Assembly

Time: 2 Hours | Type: Individual

Resources Required:

  • A3 drawing sheets (4 sheets)
  • Pencils HB and 2B
  • Scale ruler (metric)
  • PPE: None required

At the Kenya Electricity Generating Company (KenGen) geothermal plant in Naivasha, you are required to sketch and dimension an industrial valve assembly used in steam lines.

Tasks:
i. Sketch a front elevation of the valve assembly showing body, bonnet, and actuator.
ii. Draw a sectional view detailing the valve seat and disc.
iii. Add all relevant dimensions using engineering scales.
iv. Label components and indicate material specifications.

Assessor Observation Criteria:

  • [ ] Proportional accuracy of valve components
  • [ ] Clarity and correctness of sectional view
  • [ ] Proper dimensioning and labeling
  • [ ] Compliance with BS EN ISO drawing standards

Practical 6: Creating Pictorial Drawing of a Pipeline Flange Joint

Time: 2.5 Hours | Type: Individual

Resources Required:

  • Drawing board
  • Pencils 2H and HB
  • Scale ruler
  • Set squares
  • PPE: None required

As a technician at the Kenya Pipeline Company (KPC) Eldoret depot, you are to prepare a pictorial drawing of a pipeline flange joint used in chemical transfer lines.

Tasks:
i. Draw an isometric pictorial of the flange joint showing bolts, nuts, gasket, and flanges.
ii. Indicate bolt hole pattern and gasket seating area.
iii. Dimension the flange diameter and bolt circle diameter.
iv. Label all parts using standard symbols.

Assessor Observation Criteria:

  • [ ] Accuracy of flange and bolt geometry
  • [ ] Correct representation of gasket and sealing surfaces
  • [ ] Completeness of dimensions and labels
  • [ ] Neatness and clarity of the drawing

Practical 7: AutoCAD Solid Model of a Chemical Reactor Vessel

Time: 3 Hours | Type: Individual

Resources Required:

  • Computer with AutoCAD 2023
  • Technical specifications for a cylindrical reactor vessel with hemispherical ends
  • PPE: None required

At the Kenya Tea Development Agency (KTDA) factory in Kericho, you are tasked with producing a 3D solid model of a chemical reactor vessel used for tea extract preparation.

Tasks:
i. Model the main cylindrical body of the reactor vessel with length 1500mm and diameter 800mm.
ii. Add hemispherical end caps to both ends.
iii. Insert nozzle openings of diameter 100mm at specified positions.
iv. Generate orthographic views and a shaded isometric view.

Assessor Observation Criteria:

  • [ ] Correct dimensions and shapes of vessel components
  • [ ] Accurate placement of nozzles
  • [ ] Completeness and clarity of orthographic and isometric views
  • [ ] Use of layers and line types consistent with standards

Practical 8: Developing Flat Pattern Layout for a Rectangular Duct Transition

Time: 2 Hours | Type: Individual

Resources Required:

  • Drawing board
  • Ruler 300mm
  • Protractor
  • Pencil HB
  • PPE: None required

You are working on a ventilation system installation at a Moi Teaching and Referral Hospital in Eldoret and need to develop a flat pattern for a rectangular duct transition piece.

Tasks:
i. Given inlet dimensions 600mm x 400mm and outlet dimensions 400mm x 300mm with length 1000mm, calculate the development.
ii. Construct the flat pattern for the transition piece.
iii. Mark cutting lines and fold lines clearly.
iv. Label all dimensions and angles.

Assessor Observation Criteria:

  • [ ] Accurate calculation and construction of flat pattern
  • [ ] Clear indication of cutting and fold lines
  • [ ] Correct dimensioning and labeling
  • [ ] Neatness and adherence to drawing conventions

Practical 9: Sketching Orthographic Views of a Heat Exchanger

Time: 2.5 Hours | Type: Individual

Resources Required:

  • A3 drawing sheets (4 sheets)
  • Mechanical pencils 0.5mm
  • Scale ruler (metric)
  • PPE: None required

At the Athi Water Services Board in Nairobi, you have to produce orthographic drawings of a shell and tube heat exchanger used in water treatment.

Tasks:
i. Sketch the front view showing shell, tube bundle, inlet and outlet nozzles.
ii. Sketch the top view indicating tube layout.
iii. Sketch the side view showing support brackets.
iv. Add dimensions and label all parts.

Assessor Observation Criteria:

  • [ ] Proportional accuracy of all views
  • [ ] Completeness of views as per instructions
  • [ ] Proper dimensioning and labeling
  • [ ] Line quality and neatness

Practical 10: Creating a Solid Geometry Drawing of a Flanged Pipe Bend Using AutoCAD

Time: 3 Hours | Type: Individual

Resources Required:

  • Computer with AutoCAD 2023 installed
  • Specifications for a 90-degree flanged pipe bend, diameter 500mm
  • PPE: None required

At the Kenya Electricity Transmission Company (KETRACO) workshop in Nairobi, you are required to produce a 3D solid model of a flanged pipe bend used in chemical cooling water circuits.

Tasks:
i. Model the 90-degree pipe bend with flange ends.
ii. Add bolt holes on flanges as per specification.
iii. Produce orthographic views including sectional views showing flange thickness.
iv. Annotate the drawing with dimensions and material notes.

Assessor Observation Criteria:

  • [ ] Accuracy of pipe bend radius and flange dimensions
  • [ ] Correct placement and sizing of bolt holes
  • [ ] Completeness of sectional and orthographic views
  • [ ] Proper use of layers and line types

Practical 11: Manual Sketching of a Chemical Storage Tank Foundation Plan

Time: 1.5 Hours | Type: Individual

Resources Required:

  • A3 drawing sheets (3 sheets)
  • Pencils HB and 2B
  • Scale ruler (metric)
  • PPE: None required

At the Nairobi City Water and Sewerage Company, you are tasked with sketching the foundation plan for a chemical storage tank installation.

Tasks:
i. Sketch the top view showing tank base, anchor bolts, and foundation dimensions.
ii. Indicate reinforcement bar positions and sizes.
iii. Add sectional details of the foundation depth and concrete layers.
iv. Label all parts and dimensions clearly.

Assessor Observation Criteria:

  • [ ] Accuracy of foundation dimensions
  • [ ] Correct representation of reinforcement layout
  • [ ] Completeness of sectional details
  • [ ] Clarity and neatness of the sketch

Practical 12: Developing a Pattern for a Cylindrical Shell with a Side Nozzle

Time: 2 Hours | Type: Individual

Resources Required:

  • Drawing board
  • Compass (up to 200mm radius)
  • Ruler 300mm
  • Pencil HB
  • PPE: None required

You are working at the Kenya Sugar Research Foundation (KESREF) in Kisumu and need to prepare a flat pattern for a cylindrical shell with a side nozzle opening.

Tasks:
i. Determine the development for a cylindrical shell 800mm diameter, 1200mm length.
ii. Develop the flat pattern for the shell including the cutout for the side nozzle.
iii. Mark seam allowances and cutting lines.
iv. Label all dimensions and nozzle position.

Assessor Observation Criteria:

  • [ ] Correct calculation of shell circumference and length
  • [ ] Accurate placement and size of nozzle cutout
  • [ ] Clear marking of seam allowances
  • [ ] Proper labeling and dimensioning

Practical 13: AutoCAD Drawing of a Chemical Filter Housing Assembly

Time: 3 Hours | Type: Individual

Resources Required:

  • Computer with AutoCAD 2023
  • Technical drawings of a filter housing assembly
  • PPE: None required

At the Athi River Mining Company, you are required to produce a detailed 2D AutoCAD drawing of a chemical filter housing assembly.

Tasks:
i. Reproduce the front elevation of the filter housing with all components.
ii. Draw a sectional view showing internal filter elements.
iii. Dimension and annotate the drawing according to BS EN ISO standards.
iv. Prepare a title block with project and drafter details.

Assessor Observation Criteria:

  • [ ] Accuracy in reproducing assembly details
  • [ ] Clarity and correctness of sectional view
  • [ ] Proper dimensioning and annotation
  • [ ] Completeness and correctness of title block

Practical 14: Sketching and Dimensioning a Chemical Mixing Tank with Agitator

Time: 2 Hours | Type: Individual

Resources Required:

  • A3 drawing sheets (3 sheets)
  • Mechanical pencils 0.5mm
  • Scale ruler (metric)
  • PPE: None required

At the Bidco Oil Refineries in Thika, you are assigned to sketch and dimension a chemical mixing tank fitted with an agitator.

Tasks:
i. Sketch the front and side views of the tank showing agitator shaft and motor.
ii. Draw a sectional view to show agitator blades inside the tank.
iii. Add all relevant dimensions and labels.
iv. Indicate the flow of materials using arrows.

Assessor Observation Criteria:

  • [ ] Correct representation of tank and agitator components
  • [ ] Completeness of sectional view
  • [ ] Accuracy of dimensions and labels
  • [ ] Use of flow direction symbols

Practical 15: Developing a Flat Pattern for a Rectangular Chemical Storage Bin

Time: 2 Hours | Type: Individual

Resources Required:

  • Drawing board
  • Pencil HB and eraser
  • Ruler 300mm
  • PPE: None required

At the Kenya Sugar Company in Mumias, you are required to develop a flat pattern for a rectangular chemical storage bin with dimensions 1200mm x 800mm x 1000mm.

Tasks:
i. Calculate the development of all sides including base and top.
ii. Construct the flat pattern layout on the drawing sheet.
iii. Mark fold lines and cutting lines.
iv. Label all dimensions and material thickness.

Assessor Observation Criteria:

  • [ ] Accuracy of flat pattern dimensions
  • [ ] Proper marking of fold and cutting lines
  • [ ] Completeness of labeling and dimensioning
  • [ ] Neatness and clarity of the drawing
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← Ch 5: Produce pictorial and orthographic… Ch 7: Draft chemical process equipment →