| 词条 | Concrete pump | ||||||||
| 释义 |
A concrete pump is a machine used for transferring liquid concrete by pumping. There are two types of concrete pumps. The first type of concrete pump is attached to a truck or longer units are on semi-trailers. It is known as a boom concrete pump because it uses a remote-controlled articulating robotic arm (called a boom) to place concrete accurately. Boom pumps are used on most of the larger construction projects as they are capable of pumping at very high volumes and because of the labour saving nature of the placing boom. They are a revolutionary alternative to line-concrete pumps. The second main type of concrete pump is either mounted on a truck or placed on a trailer, and it is commonly referred to as a line pump or trailer-mounted concrete pump. This pump requires steel or flexible concrete placing hoses to be manually attached to the outlet of the machine. Those hoses are linked together and lead to wherever the concrete needs to be placed. Line pumps normally pump concrete at lower volumes than boom pumps and are used for smaller volume concrete placing applications such as swimming pools, sidewalks, and single family home concrete slabs and most ground slabs. There are also skid mounted and rail mounted concrete pumps, but these are uncommon and only used on specialized jobsites such as mines and tunnels. HistoryUntil the early 20th century, concrete was mixed on the job site and transported from the cement mixer to the formwork, either in wheelbarrows or in buckets lifted by cranes. This required a lot of time and labor. In 1927, the German engineers Max Giese and Fritz Hull came upon the idea of pumping concrete through pipes. They pumped concrete to a height of {{convert|38|m|ft|sp=us}} and a distance of {{convert|120|m|yd|sp=us}}. Shortly after, a concrete pump was patented in Holland in 1932 by Jacob Cornelius Kweimn (Jacobus Cornelius Kooijman). This patent incorporated the developer's previous German patent.[1] MechanismConcrete pump designers face many challenges because concrete is heavy, viscous, abrasive, contains pieces of hard rock, and solidifies if not kept moving. Usually, piston pumps are used, because they can produce hundreds of atmospheres of pressure. Such piston-style pumps can push cylinders of heterogenous concrete mixes (aggregate + cement). The pump below uses a transfer tube valve, and the one on the right uses seat valves. Example of pump performanceTo illustrate, below are data on a typical concrete sample pump BRF 42.14 H:
GallerySee also
References1. ^{{cite book|author=Illingworth J.R.|title=Movement and Distribution of Concrete|page=132|isbn=978-0070942363|publisher=McGraw-Hill|year=1972|url=https://www.amazon.com/Movement-distribution-concrete-J-Illingworth/dp/0070942366|accessdate=2012-06-18}} {{Concrete navbox}} 6 : Concrete|Construction equipment|Articles containing video clips|German inventions|1928 in Germany|1928 in science |
||||||||
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。