Model Design for Water Wheel Control System of
- Author: Kim Sang Hyuk, Ham Seon Young, Lee Yong Sam
- Publish: Journal of Astronomy and Space Sciences Volume 33, Issue1, p55~62, 15 March 2015
Heumgyeonggaknu(欽敬閣漏) is powered by a water-hammering-type water wheel. The technique that maintains the constant speed of the water wheel is assumed to be the one used in the Cheonhyeong(天衡) apparatus in Shui Yun Yi Xiang Tai(水運儀象臺) made by the Northern Song (北宋) dynasty in the 11th century. We investigated the history of the development and characteristics of the Cheonhyeongapparatus, and we analyzed ways to transmit the power of Heumgyeonggaknu. In addition, we carried out a conceptual design to systematically examine the power control system. Based on the conceptual design, we built a model for a water wheel control system that could be used in experiments by drawing a 3D model and a basic design.
Heumgyeonggaknu , Cheonhyeong (oriental escapement) , water wheel , water-hammering type
Heumgyeonggaknu(欽敬閣漏) was an automatic clepsydra made by Jang Young-sil in 1438. Gasan(假山, imitation mountain) in Heumgyeonggaknuhad 37 time-signal puppets and informed people of the time of day. Gasanwas decorated with a five-colored cloud, and it worked as an astronomical clock according to the Sun and seasons. We analyzed the modeling of the external structure through the study of Kim et al. (2011, 2013), based on the annals of the Joseon dynasty. We analyzed the internal structure through related relics ( Jagyeoknuin Korea, a restoration model of Shui Yun Yi Xiang Tai(水運儀象臺, a water-driven astronomical clock tower made in 1092) in China, Japan, etc.) . In this study, we examined the form of the Cheonhyeong(天衡, oriental escapement) apparatus and the water wheel to understand the structure of the power system in Heumgyeonggaknu. We drew a basic design and made an experimental model of the water wheel control system. Cheonhyeongwas a type of scale device. According to the Xin Yi Xiang Fa Yao(新儀象法要) written by Su Song (蘇頌, 1020–1101), it was used to control the water wheel installed inside Shui Yun Yi Xiang Tai(水運儀象臺). It measured the weight of Sususang(受水箱, scoop), which hung on the water wheel. The Cheonhyeongapparatus was first found in the Steelyard Clepsydra (稱漏), made by Li Lan (李蘭) in the 5th century, Northern Wei (北魏, 386–534 A.D.).
Fig. 1 is a structural drawing of the Steelyard Clepsydra. If a constant level of water in
Dongbun(see Fig. 1, No. 2, hereafter referred to by its number) was supplied to Dongho(9), hung on Ching(7), through Galo(4), it would let us know how much time had passed by measuring the weight of the water. To maintain a constant water pressure in the PaSuho(播水壺, water supplying vessel), a water floating vessel was used in the Steelyard Clepsydra. The water supplied from the vessel ( Dongbun) was filled in Dongho(9) at a constant speed. As water was continuously filled, a lapse of time could be produced by making a scale horizon, moving the weight (12) that hung on the scale. As time passed (as water was filled), the position of weight was manually moved left, and it made horizon. This way of using the scale was also applied to Shui Yun Yi Xiang Tai.
Fig. 2 is the
Cheonhyeongapparatus, which was applied to Shui Yun Yi Xiang Tai. There were two Cheonhyeongapparatuses in Shui Yun Yi Xiang Tai1. The first apparatus generated signals by measuring the weight of Sususangof the water wheel. (This was called “Chuhyeong”in Xin Yi Xiang Fa Yao. From now on, we refer to this as the Chuhyeongapparatus.) The second Cheonhyeongapparatus controlled the running of the water wheel according to a signal generated by the Chuhyeongapparatus.
The running mechanism of
Cheonhyeongis as follows: Gyeokcha(see Fig. 2, No. 9, hereafter referred to by its number) of Chuhyeong, senses the weight of the water filled in Sususang of the water wheel. As the water in Sususangis getting filled, Gyeokchapushes Cheonhyeonggwanseol(5). At this moment, Cheonjopulls Cheonhyeong, and Cheongwan(3) and Jwacheonswae(6) go up. The water wheel spins, and Cheongwan and Jwacheonswaebrake the water wheel. By repeating this operation, the spinning of the water wheel is controlled. Ucheonswae(7) prevents the backspin of the water wheel. The weight of Cheonhyeongis Cheongwon(2), and the weight of Chuhyeongis Chugwon(8). In the middle of Cheonhyeongthere is an axis made with steel. It passes through Cheolhyeop(1). Poured water from Sususangof the water wheel fills ToeSuho(10).
Meanwhile, in China, a single-stage clepsydra (單級浮箭漏) was made in the 1st century B.C.. A two-stage clepsydra (二級補償型浮箭漏) was made in the early years of the East Han dynasty, a three-stage clepsydra (三級補償型浮箭漏) was made in the middle of the 4th century, a steelyard clepsydra was made in the 5th century, and a four-stage clepsydra (四級補償型浮箭漏) was made in the 7th century during the early years of the Tang dynasty (Pan 2005). Increasing the number of vessels of the clepsydra was an advanced technique that achieved a constant flow velocity. Using
Dongbunfloating on the water, Ching(秤, scale) on the steelyard clepsydra, and a four-stage PaSuho on the clepsydra, a constant flow velocity was maintained and measured. Finally, these were combined to control the power of the water wheel and became the main components of the water wheel control system.
In Europe, escapement was used to increase the accuracy of mechanical clocks. Escapement had been used since the 14th century. At first, a foliot type of escapement was generally used before Huygens’ pendulum-type escapement was applied in 1657. Fig. 3 shows the changing process of how fluid was controlled in the clepsydra using mechanical escapement from the 14th century to the 17th century2. The method of escapement used in Europe was already similar to methods of controlling water used in China and nearby countries. This controlled the water level by using a scale, such as a steelyard clepsydra, or by placing several advanced vessels into a mechanical escapement from Europe3.
A preceding study (Kim et al. 2011, 2013) reported that the main power of
Heumgyeonggaknuresults from a method of running the water wheel and a two-stage clepsydra with an overflow function. To rotate the water wheel at a constant speed, a device to control the running of the water wheel is needed. The Cheonhyeongapparatus mentioned earlier is an effective way to control the running of the water wheel. However, in the development process for the clepsydra, water could already flow at a constant speed in the four-stage clepsydra, and a stable flow velocity could be maintained to rotate the water wheel in a two-stage clepsydra with overflow. Why do we need an extra Cheonhyeongapparatus to control the water wheel?
Comparing the four-stage clepsydra with the two-stage clepsydra with overflow, it made poeple use space effectively. However, the
Suho(vessel) in a two-stage clepsydra should be filled frequently by the water supply. That is, the water level of the last Suhocould be maintained for a long time with one water supply in a four-stage clepsydra, but water should be supplied more frequently in a two-stage clepsydra with overflow. In Heumgyeonggaknu, a two-stage clepsydra with overflow was used (Kim et al. 2013). This method was already shown in the running of PaSuhoof Borugaknu(報漏閣漏, made in 1434) (Nam 2002). However, to minimize the frequent water supply, the flow of water to Sususangwould be reduced. Then the space could be used effectively, and the water wheel could be rotated with limited water.
However, a problem occurred. If the amount of water was small, the initial power of rotation could not be assured. To solve the problem, the water supply should be increasedand continuously supplied. Therefore, a way to maintain the flow velocity and to rotate the water wheel of the two-stage clepsydra with overflow was needed. This was possible by combining the clepsydra and
Cheonhyeongapparatus. That is, the way to control the water wheel required a minimum flow of water, and powerful rotation power could be gained instantly by using Cheonhyeong. Therefore, a combination of the clepsydra and Cheonhyeongapparatus for space efficiency and minimizing flow could be evaluated as an innovative way to control the water wheel.
Sususang(scoop) is the equipment that receives water from the clepsydra hanging at the water wheel. Two kinds of Sususang, linked with Cheonhyeongapparatus of Shui Yun Yi Xiang Taiin Xin Yi Xiang Fa Yao, are known (see Fig. 4). Yamada & Tsuchiya (1997) considered the form of Sususangas a flip type. A flip-type scoop could make Sususangwork when the water wheel stopped. That is, when the water wheel stopped, the weight of the water in Sususangwas measured, and then a signal was given when Sususangwas folded as the constant water was filled.
By contrast, Sun Xiaochon insisted the type of
Sususangwas a fixed type, and suggested a model based on this type (see Fig. 5)4. Sun Xiaochon judged that there is no flip-type scoop in the Chinese traditional water wheel, and this type was not found in Xin Yi Xiang Fa Yao. Therefore, he insisted that the form of Sususangstudied by Yamada & Tsuchiya (1997), was incorrect. In Xin Yi Xiang Fa Yao, there was only a statement saying the number of Sususangwas 36, not 48. There was no statement related to the type of Sususang(fixed type or flip type).
To realize two kinds of
Sususang, the movement of Cheongwan(see Fig. 2, No. 3) installed upward of the water wheel was different. Yamada & Tsuchiya (1997) realized the movement of Cheongwanon a fixed axis, while Sun Xiaochon suggested that the axis of Cheongwanmoved according to the movement of Cheonhyeong. Realizing that the running of Sususangwas of the fixed type, Sun Xiaochon cleared a space at the connection of the water wheel and Cheongwanto run and brake the water wheel effectively.
Regarding the form of
Cheongwan, the forms of “^” and “|” were suggested in Xin Yi Xiang Fa Yao(see Fig. 2, No. 3 and Fig. 3, arrow part of Shui Yun Yi Xiang Tai) in 1092. However, two researchers mentioned above suggested the “^” type. The restoration models in China, Japan, and Taiwan were all of the “^” type5. However, Yip (2006) suggested the “|” type of Cheongwanfor the restoration modeling of Shui Yun Yi Xiang Tai.
Fig. 6 is the traditional Korean water wheel in
Imwongyeongjaeji(林園經濟志). The typical type of water wheel has a structure in which the water wheel is spun with filled water and transmits the power or uses the power of the spin. Sometimes it moves water upward, and a cylindrical vessel to move water upward is attached. This cylindrical vessel can be considered a type of Sususangthat is fixed rather than folded or moved.
Three hundred years after
Heumgeonggaknuwas made in the era of King Sejong, Hong Dae-yong’s Honsangui(water-hammering type celestial globe) was made. In the Honsangui, the spin of the water wheel was controlled by Sususangand Cheolcheok(Park 2011; Lee et al. 2013). Cheolcheok(鐵尺) with elastic power was used instead of the Cheonhyeongapparatus, and Sususangwas fixed. Jeon (1994) said that the water wheel usually used in the reign of King Sejong, and one in Lee Min Cheol’s armillary clock made in the 17th century, were Tongcha(筒車). In Imwongyeongjaeji, the part that was filled with water in the structure of Tongchawas fixed. Thus the water wheel and Sususangof Heumgyeonggaknuwere Tongchaand of the fixed type, respectively.
1「新儀象法要」, 天衡: 右天衡一, 在樞軸之上. 中爲鐵關軸, 於東天柱間橫桄上, 爲駞峰植兩鐵頰, 以貫其軸, 常使轉動. 天權一掛於天衡尾. 天關一掛於腦. 天條一 (即鐵鶴膝也) 綴於權裏, 右垂 (長短隨樞輪髙下), 天衡關舌一, 末爲鐵關軸, 寄安於平水壺架南北桄上, 常使轉 動, 首綴扵天條, 舌動則關起. 左右天鏁各一, 末皆爲關軸, 寄安左右天柱橫桄上, 東西相對, 以拒樞輪之輻. 樞衡, 樞權各一, 在天衡關舌上, 正中爲關軸, 於平水壺南北橫桄上爲兩頰, 以貫其軸, 常使運動. 首爲格叉, 西距樞輪受水壺. 權隨於衡, 東隨水壺, 虛實低昂. 2Clepsydra and Clock Figure Source: 5th Century Steelyard Clepsydra (Yip 2006), 7th Century Four-Stage Clepsydra (Korea Astronomy and Space Science Institute), 1092 Water-Driven Astronomical Clock Tower (Xin Yi Xiang Fa Yao), 1370 Vick’s Clock (Usher AP, A History of Mechanical Inventions, Harvard University Press, 1954), 15th Clock (Sobel D, The Illustrated Longitude, Thinking Tree Publication Co., 1995), Foliot type (Barnett JE, Time’s Pendulum: From Sundials to Atomic Clocks, the Fascinating History of Timekeeping and How Our Discoveries Changed the World, Harvest Books, 1999), Pendulum type (Edmund B, Clocks & Watches and Bells, Crosby Lockwood and Co., 1883), 1657 Clock (Britten FJ, Former Clock & Watchmakers and Their Work, Spon & Chamberlain, 1894) 3Yan HS, Lin TY, A Systematic Approach to the Reconstruction of Ancient Chinese Escapement Regulators, Proceedings of ASME 2002 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 407-414 (2002) 4Sun Xiaochun introduced the type of Sususang hung on a water wheel in the restoration model of Shui Yun Yi Xiang Tai, which was displayed as a fixed type at IAU 28th General Assembly (Beijing, China, August 20–31, 2012) 5Research on Chinese Relics: Kim, Sang Hyuk, Choi, Yong Sik, and Yang, Hong-Jin, 2012. 8., IAU Special Exhibition, Beijing. Research for Japanese Relics: 2006. 10., Kim, Sang Hyuk, Lee, Yong Sam, and Jeon, Sang-Woon, Suwako Watch & Clock Museum, Nagano. Research for Taiwanese Relics: Kim, Sang Hyuk and Lee Yong Sam, 2014. 2., National Museum of Natural Science, Taichung.
A water wheel model, the power-generating instrument of
Heumgyeonggaknu, was designed. Before the design, a test model was made to run a basic test and check the concept of each part (see Fig. 7). Using a slotted angle, water wheel (F.R.P. model), wood, and so on, the rotation of the water wheel, running of Jwa-U Cheonswae, and the roles of Chuhyeongand Cheonhyeongwere checked. Based on this, two Cheonhyeongs( Chuhyeongand Cheonhyeong), weights ( Cheongwanand Chugwan), Cheongwan, Cheonjo, Cheonhyeonggwanseol, Gyeokcha, and Jwacheonswaeand Ucheonswaewere included. In addition, Sususangwas designed as a fixed type.
Fig. 8 shows the 3D modeling of the water wheel control system of
Heumgyeonggaknuand the names of the structures. The water wheel control system consists of a water wheel, control device, and water wheel frame. In the water wheel, we draw 16 Sususang(Fig. 8 No. 13, hereafter referred to by its number) and Sususangplates (places with an interval of 22.5°). Sususangwas rectangular shaped and fixed on the Sususangplate. The Sususangplate stuck out slightly from the round disk on the side of the water wheel. This made Jwacheonswaeand Ucheonswae(7 and 8) meet the Sususangplate. In addition, a round stick was attached to the Sususangplate to sense the weight of Sususangor to be used in braking the water wheel.
The control device consisted of
Cheonhyeong(1), Chuhyeong(2) and Jwa, U Cheonswae. Cheonhyeongpassed through the “ ”-shaped of Cheolhyeopand moved. In this design, Cheongwan(4) was “^”- shaped. This caught the Sususangaround the ceiling in a stable fashion, and it was easy to run the water wheel by pushing Sususangwhen the wheel spun. In addition, a furrow was made on Cheongwanto control the length or weight of Cheongwan. This easily controlled the water wheel, and it was considered to be better than the “|”- type Cheongwan.
Fig. 9 shows the parts of the water wheel control system. There is a furrow on the end of
Gyeokchaof Chuhyeong, and the thread that is tied at Cheonhyeonggwanseol(Fig. 8, No. 6) goes through it (Fig. 9, A left). We simplified the control and transmission of power by designing the running axis of Chuhyeongand Cheonhyeonggwanseolas box shaped to move at the same time. Cheonswaeis installed at the right and left sides of the water wheel (Fig. 9, B and B’). A streamlined board (Fig. 9, B) was attached to the Jwacheonswaeto minimize the frictional force with the round stick of the Sususangplate.
The slotted angle that was used in the test model for the water wheel was used in the water wheel frame. It was designed such that the vertical and horizontal frame was installed after four columns were built, and then the water wheel was attached to the middle. In addition, we designed each part to fix
Cheonhyeong, Chuhyeong, and Jwacheonswaeand Ucheonswae.
Fig. 10 is the running mechanism of the water wheel control system. As seen at A, the water flow into Sususang and
Cheonhyeonggoes down. Then it pushes down the Cheonhyeonggwanseol(see Figs. 9 and 10). The power transmitted to Cheonhyeongis divided in two. At B, Jwacheonswaegoes up, and Cheongwangoes up at C. Now the water wheel is unlocked and spins 22.5°. Then Jwacheonswaegoes down at B and Cheongwangoes down at C to brake the water wheel. At B’, Ucheonswaeis locked to prevent backspin. This running mechanism is repeated, and power is generated at regular intervals. Then the power generated at the water wheel transmits to the running system in order to operate the time signal system of Heumgyeonggaknu. Fig. 11 shows the water wheel system, newly made after the basic design based on the 3D modeling and test model. Hereafter, we hope that a detailed study about power system will be carried out using this kind of water wheel control system.
The water wheel in
Heumgyeonggaknucan be controlled by using the Cheonhyeongapparatus. The origin of the Cheonhyeong apparatus was the Steelyard Clepsydra, and it was applied to Shui Yun Yi Xiang Tai, which was completed in 1092. Cheonhyeongapplied to Shui Yun Yi Xiang Tairegulated the rotation velocity of the water wheel. It seemed that the control of the water wheel used the function of escapement, which was known to control European mechanical clocks.
The water wheel of
Heungyeonggaknuwas understood to be either a type with a scale apparatus to control the flow of water, or a two-stage clepsydra with overflow. The water from the clepsydra filled in Sususang, and the Chuhyeongapparatus ran when the water of Sususangreached a particular weight. At that time, the power was transmitted to the Cheonhyeongapparatus installed on the water wheel, and the water wheel ran as the Jwacheonswaeand Cheongwanunlocked. The combination of the water wheel and the Cheonhyeongapparatus caused a powerful turning force with limited water, and it was considered an advanced technique to control the water wheel.
We carried out an operational experiment of a water test model, and used 3D modeling based on an experiment of
Xin Yi Xiang Fa Yaoand the traditional Korean water wheel. In addition, we drew the basic design of the main parts: the water wheel, fixed-type Sususang, Cheonhyeong, Chuhyeong, Cheonhyeonggwanseol, Jwa-U Cheonswae, and Gyeokchaof the water wheel control system of Heumgyeonggaknu, etc. We built a model for the experiment. In the future, we will use the model for water wheel control experiments.
[Fig. 1.] Structural drawing of Steelyard Clepsydra (Pan 2005).
[Fig. 2.] Cheonhyeong apparatus of Shui Yun Yi Xiang Tai (source: Xin Yi Xiang Fa Yao).
[Fig. 3.] Change process of method of counting time in East Asia and Europe.
[Fig. 4.] Sususang’s two types of working form.
[Fig. 5.] (a) Shui Yun Yi Xiang Tai, restored in 2012, and (b) water wheel model of fixed-type scoop.
[Fig. 6.] Water wheel form in Imwongyeongjaeji.
[Fig. 7.] Test model for water wheel.
[Fig. 8.] 3D modeling of water wheel control system of Heumgyeonggaknu, and names of structures.
[Fig. 9.] Parts of water wheel control system.
[Fig. 10.] Running mechanism of water wheel control system.
[Fig. 11.] Experimental model of water wheel control system of Heumhyeonggaknu.