Pressure suit
A pressure suit is a
Background
The region from sea level to around 3,000 m (10,000 ft) is known as the physiological-efficient zone. Oxygen levels are usually high enough for humans to function without
The physiological-deficient zone extends from 3,600 m (12,000 ft) to about 15,000 m (50,000 ft). There is an increased risk of problems such as
Methods of operation
Generally, pressure suits work by either indirectly compressing the human body, or directly compressing it.
Indirect compression
Indirect compression is typically done by enclosing the body in a gas envelope. For this type, design effort focuses on compressing and containing the gas, at an equal pressure around the body as the wearer moves, and not having the gas pressure or the enclosing suit envelope restricting body movement of the wearer.
Maintaining constant gas pressure as the wearer moves is difficult, because the internal volume of a simple construction inflatable suit will change when body joints are flexed. The gas pressure constantly tries to push the wearer's body into a position where the suit has been inflated to its maximum volume. Moving against this gas pressure can be very difficult, and be very exhausting for the suit wearer, limiting the amount of work that can be performed using the suit.
Indirect compression suits generally require complex ribbed mechanical structures at the joints, which create flexible but inelastic folds or pockets in the skin of the suit that act to maintain a constant volume in the suit as the wearer moves. These pockets exist on both sides of a flexible joint and are designed to work together in tandem, so that when a joint is flexed, the folds on one side of the joint will compress and shrink in volume, while the folds on the opposite side will relax and expand in volume. The ribbed structures are usually braced with wire cables or cloth straps to limit their motion and prevent unusual flexing modes that may chafe against the user's body. The wire hinge cables also restrain the complex folds, which if released could unfurl and extend to be more than a meter longer than the wearer's body.
These constant-volume joint structures greatly reduce fatigue of the wearer so that they do not have to constantly struggle against the suit pressure.
Direct compression
Direct compression involves applying pressure directly to the human body using the suit material, usually without any additional gas envelope around the wearer, which is instead provided by an outer rigid cabin structure enclosing the person.
One method used for this is known as a capstan suit, which uses a compressible inflatable tube known as the capstan, enclosed by alternating fabric strips that wrap around the air tube and are attached to an inelastic fabric that closely fits the shape of the wearer's body.
To provide a custom tight form-fit to the wearer's body, there are groups of laces along the length of each limb. Zippers may also run the length of a limb to allow for room to get into the suit. To apply pressure, the capstan tube is pressurized which expands in diameter and applies pressure to the fabric strips. The strips then pull the suit material laterally tighter around the wearer's body.
A problem with this design is that the suit fabric is unable to directly provide pressure to the human body in areas with a surface that curves inward, away from the suit fabric. Locations with concave skin surfaces are in the armpit, behind the knees, the front and back of the crotch region, and along the spine.
Inflatable air bladder structures or molded rigid expanded foam may be used, which fit into these cavity spaces to provide direct skin pressure where the suit material is unable to provide that contact directly.
Types
Partial pressure suits only pressurize certain parts of the body. They can only provide protection up to a certain altitude.[3] They do not provide protection for extended periods of time at low ambient pressure.[4] Full pressure suits pressurize the entire body. These suits have no altitude limit.[citation needed]
Exposure to space without a spacesuit
This section may contain material not related to the topic of the article and should be moved to space suit instead. (August 2020) ) |
The human body can briefly survive the hard
Human skin does not need to be protected from vacuum and is gas-tight by itself.
History
USSR
In USSR, the first full pressure suit was designed by engineer
Haldane-Davis
In 1931, American Mark Ridge became obsessed with breaking the world altitude record in an open gondola balloon. Recognizing that the flight would require specialised protective clothing, he visited the UK in 1933 where he met with
On 28 September 1936
Wiley Post
In 1934, aviator
World War II
In the US, a large amount of effort was put into the development of pressure suits during World War II. While B.F. Goodrich led the field, other companies involved in such research included the Arrowhead Rubber Co., Goodyear, and US Rubber. The University of Minnesota worked with Bell Aircraft and the US National Bureau of Standards. The Bureau of Standards and the University of California acted as clearing houses to distribute information to all the companies involved. No effective fully mobile pressure suits were produced in World War II but the effort provided a valuable basis for later development.[9]
David Clark Company
Following the war, the
Goodrich Mk III and IV
US requirements for high-altitude reconnaissance aircraft such as the
RAF
The RAF Institute of Aviation Medicine and the Royal Aircraft Establishment developed a partial-pressure helmet which was used with a capstan type suit purchased from the US. It was worn by Walter Gibb and his navigator to set a world altitude record on 29 August 1955 in an English Electric Canberra. However, evaluation of the suit showed that it encumbered the wearer and did not integrate well with RAF escape systems. Instead, the RAF IAM proposed a minimal-coverage suit which would provide "get-me-down" protection. The RAF never issued a partial-pressure suit, preferring instead to use anti-g trousers in conjunction with pressure jerkins (which applied mechanical counter-pressure to the wearer's chest).
See also
- Dive Bomber – 1941 film, 1941 film featuring scenes portraying the development of the pressure suit.
- Environmental suit – Clothing worn to protect a person in a hostile environment
- Flight suit – Full-body garment
- Horten Ho 229 – German prototype fighter/bomber (1944)
- Mechanical counterpressure suit – Spacesuit providing mechanical pressure using elastic garments
- Navy Mark IV– full-body pressure suit for wear in high-altitude fighter aircraft operations
- Positive pressure personnel suit – Air-tight industrial protection garment
- Space suit – Garment worn to keep a human alive in the harsh environment of outer space
Notes
- ^ "Altitude". altitude.org. Retrieved October 30, 2023.
- ^ "Aviation Supplemental Oxygen". www.cfinotebook.net. Retrieved October 30, 2023.
- ISBN 0-87474-459-8.
- ^ Hoffman, Stephen. "Advanced EVA Capabilities: A Study for NASA's Revolutionary Aerospace Systems Concept Program" (PDF). Houston, Texas: NASA. p. 55. Archived from the original (PDF) on 27 July 2011. Retrieved 3 April 2011.
- ^ "Ask an Astrophysicist, Human Body in a Vacuum". NASA's Imagine the Universe. Retrieved 2008-12-14.
- ^ "Outer Space Exposure". Damn Interesting. Retrieved 2008-12-14.
- ^ "The A-Z of skin – Skin structure and function". Australasian College of Dermatologists. Retrieved 2020-01-23.
The skin is an organ that provides the outer protective wrapping for all the body parts. It is the largest organ in the body. It is a waterproof, airtight and flexible barrier between the environment and internal organs. It keeps the internal environment of our body stable.
- ISBN 1-85233-732-X.
- ^ ISBN 0-387-27919-9.
- ^ Thomas, p. 10
External links
The dictionary definition of pressure suit at Wiktionary Media related to Pressure suits at Wikimedia Commons