Kettle Design Specification

Transcription

1 Kettle Design Specification 1

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3 Task 1A After looking at the product design specification, I could see issues straight away. The first one to my mind was the fact it has very little information, it has omissions. I will deal with these later on. When looking closer at the information it does have I could see some errors of a technical nature. I have tackled these by first of all highlighting and numbering them, then I will attempt to address the errors using calculation to correct. 3

4 Errors to correct (1) Electrical Rating of 1kW Most kettles have 3kW ratings because of the amount of water to boil, and time the customer is prepared to wait for it to boil. (2) Boiling time of 90 seconds Again this is incorrect due to the undersized 1kW element. (3) Weight (full) of 0.95kg This is inaccurate and hence points at the dimensions being wrong. (4) 3 Amp plug top fuse This fuse is definitely too small for a 1kW load. Calculations Fuse Design current = power / voltage I = P/U 1000w / 230v = 4.35 amps A 3A fuse is too small so a 5A fuse is needed Boiling time Energy = mass x heat x temperature Specific heat capacity water kj/kgk E = 1 kg x 4187 j/kgk x 80 ºC = joules Power = energy / time Time = energy/power T = j / 1000 W = secs 5 minutes 74 seconds if divided by 60 seconds 4

5 Electrical rating Working out sizes of element and fuse for 90 second boiling time Power = energy / time P = / 90 = r 3.72 kw heating element Design Current = Power / Voltage Ib = W / 230 V = A, so a 16A fuse is required, unfortunately a 13A is the biggest available for a British standard plug top. Solution to electrical and time issues As I said earlier most kettles have a 3kW element so need a 13A fuse, so using these figures we need a realistic boiling time. Design Current = Power / Voltage Ib = 3000 W / 230 V = A, so a 13A fuse is adequate Time = Energy / Power T = j / 3000 W = secs Size Errors Weight (empty) 0.25kg, Weight (full) 0.95kg If 1 litre of water weighs 1kg then surely the correct full weight is 1.25kg Dimensions Base unit = 120mm diameter Maximum jug diameter = 140mm Overall height = 250mm I am reducing this height to 200mm to allow for a base for electrical connections etc Volume = π x radius² x height = π x 60² x 200 x 10-6 = 2.26dm³ If 1dm³ = 1 litre then 2.26dm is larger than 1 litre I am going to reduce the radius to a 80mm diameter to achieve a 1 litre capacity, and prove the 200mm height by calculation. Volume = π x radius² x height Height = volume / π x radius² 5

6 Height = 1 / π x 40² = x 10-6 = 200mm height Task 1B Omissions from spec 1. Voltage - there was no voltage specified so I have had to assume the UK voltage of 230 Volts for my calculations. 2. Cable and plug top details there are no details on length, colour or type of cable, or even the plug type. Hopefully a heatproof 3 core flex with moulded British Standard plug top would be used. 3. Safety factors - it is essential that the kettle has a thermo cut out, this is a big safety issue to stop it boiling dry, a big danger not specified. 4. Market my issue above only assumes this item is for a U.K market as it is not stated, could it also be used in the E.U. 5. Filling Details also not stated is if there is a lid to remove for filling with water, we can only assume this is the case like most modern kettles. Task 1C Improvements to details 1. Maintenance the fuse used is not clear, if used in the U.K it would need to be stated as being a BS A. 2. Handle is the handle on top or on the side, this should be clearly stated for the customer. 3. Cost with the price tag of it is not clear whether Aquaspeed is talking about production cost or selling cost. 4. Environment the specification should state if it is just the U.K or other markets it is to be used in, e.g European. 5. Aesthetics are the kettles one colour or a mix of colours. 6

7 Task 2 New Product Specification Aquaspeed Kettle Product Customer Requirements 1. Performance 2. Environment 3. Maintenance 4. Cost 5. Appearances 6. Dimensions and Features 7. Safety Factors 1.1 Electrical rating 230V, 3kW 1.2 Boiling time 120 seconds 2.1 British Standards tested for UK Domestic use only 3.1 Fitted BS 1363 Moulded plug top with replaceable 13A fuse 3.2 Replaceable 3kW tungsten element 3.3 Replaceable water proof heatproof rubber seal 4.1 Customer price All one colour from red, green, blue, brown, or white 5.2 Easy clean plastic surfaces 5.3 Easy poor spout 5.4 Removable lid for top filling 5.5 Side mounted water level indicator 5.6 Side mounted easy grip handle 6.1 Jug and Base unit diameter 80mm, Base depth 50mm 6.2 Total height 250mm 6.3 Capacity 1 Litre 6.4 Weight (empty) 0.25kg 6.5 Weight (full) 1.25kg 7.1 Illuminated mains On/Off switch (red in colour) 7.2 Heatproof insulated and sheathed 3 core flex (500mm length) with a shrouded mains connector to base jug 7.3 BS A fuse 7.4 Thermal cut out 7