សិល្បៈ
សម្រស់ និង សុខុមាលភាព
សិប្បកម្ម
វប្បធម៌ និង ប្រវត្តិសាស្ត្រ
ការកម្សាន្ត
បរិស្ថាន
ម្ហូប និង ភេសជ្ជៈ
វិស្វកម្មបញ្ច្រាស
វិទ្យាសាស្ត្រ
កីឡា
បច្ចេកវិទ្យា
ប្រដាប់ដែលស្លៀក
The Sad Iron: Keeping the Heat in the Face, Not the Hand
Before electricity, clothes were pressed with solid irons — 'sad' meant heavy — heated on the stove and swapped as they cooled. They burned the hand through a hot handle, sent heat up into the ironer's face, and cooled fastest at the point.
Mary Florence Potts of Ottumwa, Iowa, patented two answers. US 103,501, dated 24 May 1870, makes the iron a metal shell filled on top and sides with a non-conductor such as plaster of Paris, pointed at both ends, with a wooden handle covering the metal one. US 113,448, dated 4 April 1871, adds a detachable semicircular handle that clips onto any of several hot irons, so the user keeps one cool handle and the wrist stays in line "as a person pushes a plane".
This rung models the stored heat and where it leaks, and tests an insulated block against a bare one.
ចាប់ផ្តើម
About 3 hours
ការណែនាំ
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Stored heat and the insulated top
Stored heat and the insulated top
កំពុងផ្ទុកសៀវភៅ Jupyter…
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2
Read the two patents
Read the two patents
**US 103,501 (1870):** body A flat below, rounded on top and sides, with two pointed ends; the hollow filled with a non-conductor D "flush with all the sides" that "prevents radiation of heat from every part of said iron except the bottom or face"; a wooden handle C whose ends turn down over the iron uprights E so the hand cannot touch hot metal.
**US 113,448 (1871):** a curved, semicircular handle A on a metal plate B; a latch C whose lip D passes under a cross-bar d cast inside the iron, held by a spring f so it cannot fall out when the iron is turned over; recesses h at each end that stop the handle moving sideways. The iron itself is now hollowed from the middle, with the metal made thicker at the ends, "where most heat is needed".
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The filling she used
The filling she used
Potts filled her irons with plaster of Paris among other non-conductors. The embedded blueprint covers how plaster sets and what it is made of.
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Test an insulated block against a bare one
Test an insulated block against a bare one
Take two identical steel blocks or cast-iron weights of about 1 kg. Leave one bare. On the other, build a 10 mm jacket of plaster of Paris over the top and sides, leaving the base clean, and let it dry for two days.
Heat both in an oven to about 200 °C (check with the infrared thermometer), then set each on a folded damp cotton towel on a board — the 'cloth'. Every two minutes read the base temperature through the towel's edge and the top surface. The insulated block's base stays hot longer and its top stays cool enough to hold near. Use oven gloves throughout.
សម្ភារៈសម្រាប់ជំហាននេះ៖
ដងដែកថែបឆៅ2 ដុំ
បាយអប៉ារីស1 kilogram
ក្រណាត់ហ្គោសកប្បាស1 ដុំ
សន្លឹកឈើបន្ទះ1 ដុំ
ទឹក1 លីត្រឧបករណ៍ដែលត្រូវការ៖
ទែម៉ូម៉ែត្រអ៊ីនហ្វ្រារ៉ូស
នាឡិកាបញ្ឈប់
ស្រោមដៃការងារស្បែក
ជញ្ជីងឌីជីថលផ្ទះបាយ5
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Ironing with a stove-heated iron
Ironing with a stove-heated iron
What went wrong with sad irons and why.
Flow
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History and honest limits
History and honest limits
**Mary Florence Potts** of Ottumwa, Iowa, was granted **US 103,501** (24 May 1870) and **US 113,448** (4 April 1871). Her detachable-handle irons were made in large numbers and are now common collectors' pieces; the electric iron replaced them in the twentieth century.
**Honest limits.** The heat-transfer coefficients in the notebook are illustrative and the model treats the iron as one uniform temperature. Plaster sheds water when first heated; dry the jacket fully and heat slowly.
សម្ភារៈ
5- 2 ដុំកន្លែងទុក
- 1 kilogramកន្លែងទុក
- 1 ដុំកន្លែងទុក
- 1 ដុំកន្លែងទុក
- 1 លីត្រកន្លែងទុក
ឧបករណ៍ចាំបាច់
4- កន្លែងទុក
- កន្លែងទុក
- កន្លែងទុក
- កន្លែងទុក
ប្លង់ពាក់ព័ន្ធ
ប្លង់ទាំងនេះចែករំលែកចំណេះដឹង — បច្ចេកទេស សម្ភារៈ ឬគោលការណ៍
CC0 សាធារណៈ
ប្លង់នេះត្រូវបានចេញផ្សាយក្រោម CC0។ អ្នកមានសិទ្ធិចម្លង កែប្រែ ចែកចាយ និងប្រើប្រាស់ដោយមិនចាំបាច់សុំអនុញ្ញាត។
គាំទ្រអ្នកបង្កើតដោយទិញផលិតផលតាមរយៈប្លង់របស់ពួកគេ ដែលពួកគេទទួលបាន កម្រៃជើងសារអ្នកបង្កើត កំណត់ដោយអ្នកលក់ ឬបង្កើតកំណែថ្មីនៃប្លង់នេះ ហើយបញ្ចូលជាការតភ្ជាប់ក្នុងប្លង់របស់អ្នកដើម្បីចែករំលែកចំណូល។