DEVICE FOR PREVENTING WATER-HAMMER WHILE REGULATING WATER PRESSURE

Abstract: Device (B) for preventing water-hammer while regulating water pressure includes valve-element biasing means (b) which substantially consists of a pressure-adjusting spring (d) with a small spring constant and a water-hammer preventing spring (c) with a large spring constant which are disposed in series in a valve casing. The valve-element biasing means (b) is capable of varying the opening area of a communicating passage (25) which communicates an upstream passage (R₂) with a downstream passage (R₂) so as to adjust the pressure in the communicating passage while preventing the occurrence of water-hammer in pipings and/­ water supply equipments.

Description: State of Art This invention relates to a device for preventing water-hammer which tends to occur in various types of water pipings and/or water supply equipments. Technical Background Conventionally, there have been several types of devices for preventing water-hammer which causes uncomfortable sounds in the pipings and the water leakage. In one type of valve, a sharp pressure change produced by water-hammer is absorbed by a valve element provided with a spring or a shock absorber. From FR-A-1 515 466 is known a device according to the preamble of claim 1 comprising a communicating passage formed in a valve casing to communicate an upstream passage with a downstream passage, a valve element being reciprocable in the valve casing to open or close the communicating passage, and a valve element biasing means. However, in these conventional devices for preventing water-hammer, since the retracting volume of the valve element is proportional to a flow-in-side passage pressure or an upstream-side pressure, corresponding to the pressure change in the flow-in side, the neutral position is remarkably changed. Furthermore, to absorb the sharp rise caused by the water-hammer, the valve element must be retracted moving beyond the neutral position so that the valve-moved volume becomes increased making the entire construction of the water-hammer preventing device large-sized. Still furthermore, since the water-hammer preventing device is devised for preventing exclusively water hammer, the device is not provided with a pressure adjusting function, namely, a function to bold the dynamic fluid pressure in the downstream passage of the device at constant pressure in the normal operation. Accordingly, it is an object of the present invention to provide a device for preventing water-hammer which can resolve the above-mentioned tasks. This object is obtained through a device having the features claimed in claim 1. The device for preventing water-hammer may further be characterized by being provided with an auxiliary passage capable of flowing out an amount of water which corresponds to a valve-moved volume from said upstream passage to said downstream passage corresponding to the movement of said valve element in closing direction at the time of the occurrence of water-hammer. Due to the above construction, the invention has following advantages. 1 ○ When water-hammer is about to occur, the valve element pressing pressure on the downstream passage increases far larger than the biasing force of the valve element biasing means and the valve element is rapidly moved in a valve-closing direction. In this movement of the valve element, the water-hammer preventing spring having a large spring constant can effectively absorb the pressure energy that water-hammer holds. Accordingly, the occurrence of uncomfortable sound or water leakage in various piping or equipments can be effectively prevented. 2 ○ In the normal operation, when the pressure in the downstream passage is slightly deviated or changed, the pressure adjusting spring having a small spring constant is shrinked in proportion to the deviation or change of the pressure. Due to this shrinkage, the valve element is moved in a valve-closing direction so as to accurately adjust the downstream pressure to be always constant. 3 ○ When water-hammer occurs, corresponding to the movement of the valve element in a valve-closing direction, an amount of water which corresponds to the valve-moved volume flows from the upstream passage to the downstream passage by way of the auxiliary passage so that the valve element is readily and smoothly moved. Accordingly, the pressure energy produced by the water-hammer can be readily absorbed whereby the occurrence of uncomfortable sound or water leakage in various piping or equipments can be more effectively prevented. 4 ○ The valve element is always biased in a valve-opening direction by means of the valve-element biasing means and the valve-element biasing means is constructed such that it reciprocates the valve element substantially only along with the downstream valve pressing pressure produced in the downstream passage so as to effect the pressure regulation by changing the opening area of the communication passage. Therefore, the influence of the upstream pressure produced in the upstream passage can be prevented or minimized. Accordingly, the valve-moved volume can be minimized and the device for preventing water-hammer can be made considerably compact. Brief Explanation of Drawings Fig. 1 is a front elevational view of the water mixing valve provided with the water-hammer preventing device of the first embodiment having the water pressure regulating function. Fig. 2 is an explanatory view showing the inner structure of the water-hammer preventing device. Fig. 3 is a schematic view of the water-hammer preventing device. Fig. 3A is a cross-sectional view of the valve-element provided with an auxiliary passage. Fig. 4 is a graph showing the relationship between the valve-element biasing force and the stroke of the valve element. Fig. 5 is an explanatory view showing the inner structure of the water-hammer preventing device of a modification of the first embodiment. Fig. 6 (a)(b) are schematic views of the water-hammer preventing device B. Fig. 7 (a)(b) are schematic explanatory views of a water-hammer preventing device C which is provided with only one valve element biasing spring h, i.e. not in accordance with the invention in order to show by comparison the advantages (very compact arrangement) of the device according to the invention comprising two springs in series. Fig. 8 is a side view of the water stop valve of the second embodiment of this invention. Fig. 9 is a cross-sectional view of the above valve taken along the line I-I of Fig. 8. Fig. 10 is a cross-sectional view of the above valve taken along the line II-II of Fig. 9. Fig. 11 is a cross-sectional view of the above valve taken along the line III-III of Fig. 12. Fig. 12 is a cross-sectional view of the above valve taken along the line IV-IV of Fig. 8. Fig. 13 is a cross-sectional view of the above valve taken along the line V-V of Fig. 11. Fig. 14 is a graph showing the characteristic of valve element biasing force. Fig. 15 is an explanatory view showing the manner of using the water stop valve of this embodiment. Fig. 16 is a schematic view showing the operation of the waterhammer preventing means. Fig. 17 is a front view of the water stop valve of the third embodiment of this invention. Fig. 18 is a plan view of the water stop valve of the third embodiment of this invention. Fig. 19 is a right side view of the water stop valve of the third embodiment of this invention. Fig. 20 is a left side view of the water stop valve of the third embodiment of this invention. Fig. 21 is a cross-sectional view of the above valve takes along the line VI-VI of Fig. 17. Fig. 22 is a cross-sectional view of the above valve taken along the line VII-VII of Fig. 17. Fig. 23 is a cross-sectional view of the above valve taken along the line VIII-VIII of Fig. 17. Fig. 24 is an explanatory view showing the manner of using the water stop valve of the third embodiment. Best Mode for Carrying Out the Invention This invention is explained in detail in view of following embodiments in conjunction with the attached drawings. [First Embodiment] In Fig. 1, numeral 10 indicates a mixing valve mounted on a wall W is of a bathroom for mixing cold water and hot water. The mixing valve 10 is provided with a cold-water supply passage and a hot-water supply passage at respective sides thereof. A cold-water supply tube 11 and a hot-water supply tube 12 have their respective ends connected to these passages of the mixing valve 10. In the drawing, numeral 12a indicates a spout. In this embodiment, a water-hammer preventing device B is accommodated in the cold-water supply tube 11 and the hot-water supply passage respectively. The place where the water-hammer preventing device B is to be mounted may not necessarily be restricted to the above-mentioned place, but, rather can be mounted on any other places, for example, in the mixing valve 10 or in a water stop valve as described later. The construction of the water-hammer preventing device B is explained hereinafter in view of Fig. 2 and Fig. 3 which schematically show the device. Since the construction of the mixing valve 10 per se is well known to the public, the explanation thereof is omitted. In Fig. 2, numeral 20 indicates a tubular water-supply tube body which is elevating in a slanted position toward the mixing valve 10. The water supply tube body 20 is provided with an opening 21 at the upper peripheral wall thereof which communicates with either the cold-water supply passage or the hot-water supply passage formed in the mixing valve 10, while the water supply tube body 20 is provided with a cylindrical connecting portion 22 at the lower peripheral wall which communicates with either the cold-water supply tube 11 or the hot-water supply tube 12. The water supply tube body 20 essentially consists of a water-hammer-preventing-device-mounting sleeve 23 in which a water-hammer preventing device B is incorporated therein and a water-stop-mounting sleeve 24 which is disposed in parallel to the water-hammer-preventing-device-mounting sleeve 23 . Inside the water-stop-valve mounting portion 24, a communicating passage 25 is formed and the upper end of the communicating passage 25 is communicated with a throttling portion formed in the upper space of sleeve 23 by way of an inlet opening 26 formed in the upper side wall of the sleeve 23. The lower end of the communicating passage 25 is communicated with a tubular connecting portion 22 by way of a water stop valve 29 which is provided with a strainer 28. With such construction, an upstream (primary) passage R₁ is defined in the communicating passage 25 while a downstream (secondary) passage R₂ is defined in the opening 21. To explain the construction of the water-hammer preventing device B hereinafter in more detail, letter a indicates a plunger-like valve element which is disposed in the upper portion of the water-hammer-preventing-device mounting sleeve 23 and the valve element a is axially reciprocably disposed in the sleeve 23. The valve element a is substantially made of an upper and lower enlarged-diameter portions a-1, a-2 and an intermediate narrow-diameter portion a-3. In normal spouting operation, the upper enlarged-diameter portion a-1 is disposed in the upper portion of the inlet opening 26, the intermediate narrow-diameter portion a-3 is disposed at a position in the mounting sleeve 23 which is communicated with the inlet opening 26 and the lower enlarged-diameter portion a-2 is disposed at a position below the inlet opening 26 of the mounting sleeve 23. In the bottom part of the water-hammer-preventing-device mounting sleeve 23, a valve-element-biasing means b which holds the above-mentioned valve element in place in normal flow operation is disposed. The valve element biasing means b comprises a water-hammer preventing spring c, a pressure adjusting spring d and an intermediate spring receptacle 30. The water-hammer preventing spring c has the proximal end thereof come into contact with the lower bottom wall 23a of the water-hammer-preventing-device mounting sleeve 23 and the distal or upper end thereof come into contact with the flange porton of the cup-shaped intermediate spring receptacle 30. The pressure adjusting spring d has the proximal end thereof received in the cup portion of the intermediate spring receptcle 30 and the upper end thereof received in an elongated aperture 31 formed in the inside of the valve element a while made into contact with an upper wall 32 of the valve element a. In Fig. 2, a numeral 33 indicates an air inlet formed in the lower portion of the water-hammer-preventing-device mounting sleeve 23 for making the movement of the springs c,d smooth. In Fig. 2, letter e indicates a slit formed on the outer surface of the upper enlarged-diameter portion a-1 of the valve element a and such slit forms an auxiliary passage. As described later, the auxiliary passage e can gradually decrease the amount of water which flows from the upstream passage R₁ to the downstream passage R₂ at the time the valve element a is moved in the valve-closing direction to absorb the pressure change occurred by water-hammer. The auxiliary passage e may be formed in a tapered shape on the surface of the upper enlarged-diameter portion a-1. As shown in Fig. 3A, the auxiliary passage e has a rectangular or triangular or semi-circular cross-section. In the above water-hammer-preventing device B having above-mentioned construction, among various valve-element biasing forces applied to the valve element a, an initial valve-element biasing force F₁ is set to be equal to a downstream valve-element pressing force F₂ which occurs in the downstream passage R₂ namely, F₁=F₂ . The downstream valve-element pressing force is expressed by the following formula: F₂=P₂·Av+P₁·(Ac-Av) . In the formula, P₁ is upstream pressure of the upstream passage R₁, P₂ is downstream pressure of the downstream passage R₂, Av is the area of the rear-pressure receiving surface of the valve element a and Ac is the cross-section area of the mounting sleeve 23 at the throttling portion 27. Due to such setting of parameters, in the normal flowing operation, when the upstream pressure P₁ in the upstream passage R₁ and/or the downstream pressure P₂ in the downstream passage R₂ are changed, the valve element a is moved in proportion to the amount of the pressure change and adjusts the opening area A of the throttling portion 27 so as to regulate the amount of water flowing into the downstream passage R₂ the upstream passage R₁. Furthermore, in this embodiment, as shown in Fig. 2 and Fig. 3, the value of (Ac-Av) is determined as small as possible. Namely, since the projected area which is the difference between the cross-sectional area of the mounting sleeve 23 at the throttling portion 27 and the pressure-receiving surface Av of the valve element a is determined as small as possible, the above-expressed formulae can be expressed as follows. F₁= P₂ · Av . Accordingly, in this embodiment, the valve element a is always biased in a valve-opening direction by means of a valve-element biasing means b and the valve-element biasing means b cooperates together substantially with the downstream pressure P₂ which is produced in the downstream passage R₂ to reciprocate or move the valve element a and effect the regulation of pressure by the adjustment of the opening area A of the throttling portion 27. Thereby, the adverse influence of the change of the upstream pressure P₁ can be prevented. Eventually, the valve-moved volume ( the opening area A of the throttling portion × stroke of the valve element a ) can be minimized thus making the water-hammer-preventing device B as compact as possible. Furthermore, in this embodiment, the valve-element biasing means b is made of the water-hammer-preventing spring c and the pressure-adjusting spring d which are connected in series, wherein the former spring c is made of a spring having a large spring constant k₁ while the latter spring d is made of a spring d which is made of a spring of a small spring constant k₂. Accordingly, assuming that the combined spring constant of both springs c,d is denoted by k₀, the combined force of both springs c,d, namely, the valve-element biasing force is denoted by F and the stroke of the valve element a is denoted by S, the combined spring coefficient k₀ and the valve-element biasing force F are expressed by following formula respectively. k₀= k₁ · k₂/ (k₁ +k₂) (1) F = k₀ · S = [k₁ · k₂/ (k₁ +k₂) ] S (2) Namely, the valve-element biasing force F is gradually increased until the stroke S reaches a preset value and after reaching the value, is sharply increased. Accordingly, within the range of the normal pressure change, since the combined spring constant k₀ is small, even when the downstream pressure P₂ in the downstream passage R₂ is increased slightly, the valve element a is moved proportionally to throttle the opening area A of the throttling portion 27 thus providing a pressure regulating function to the water-hammer preventing device B so as to always hold the downstream pressure at constant value. Meanwhile, when the water-hammer is produced by suddenly effecting the water stopping operation, the upstream pressure P₁ and the downstream pressure P₂ are both elevated. As a result of such pressure elevation, F₁<F₂. Accordingly, in this embodiment, the valve element a is moved in a valve-closing direction to compress the valve-element biasing means b so that the instantaneous pressure energy that water-hammer holds is transformed into the compressive elastic energy and absorbed. As shown in Fig. 4, the spring constant of the combined spring force is the spring constant k₁ of the water-hammer-preventing spring c so that even when the downstream pressure P₂ in the downstream passage R₂ is sharply increased, the valve element a is moved to throttle the opening area of the throttling portion thereby effectively absorbing the sharp pressure change caused by the water-hammer. Furthermore, in this embodiment, since the auxiliary slit e is formed on the outer surface of the valve element a, a suitable amount of water which corresponds to the valve-moved volume ( the opening area A of the throttle position 27 × stroke of the valve element a) of the valve element a is readily flown from the water-stop-valve side to the mixing-valve-side passage. Accordingly, the valve element a is readily moved in a valve-closing direction and the sharp pressure change caused by water-hammer is effectively absorbed. To explain other constructional elements or members in Fig. 2, numeral 35 indicates a cover lid, numeral 36,37 indicate O-ring and numeral 38 indicates a cap nut for connecting purposes. Fig. 5 shows a modification of this embodiment, wherein the modification has a water-hammer preventing device B′ which is similar in construction to the water-hammer preventing device B of the above-mentioned embodiment except for following construction. In lieu of the intermediate narrow-diameter portion a-3, a T-shaped flow passage which is made of an axial flow passage a-4 and a radial flow passage a-5 is formed in a valve element a, wherein the radial flow passage a-5 is communicated with the upstream passage R₁ and the upper end of the axial flow passage a-4 is communicated with the downstream passage R₂. With such construction, when the downward pressure F₂ is changed during the water spouting operation, the valve element a is always biased in a valve-closing direction and the valve biasing means b is constructed such that it substantially cooperates only with the downward valve-element pressing force F₂ to move and reciprocate the valve element a and regulate the pressure by adjusting the opening area A of the throttling portion. Accordingly, the moved-volume of the valve element a can be minimized so that the water-hammer preventing device B can be made as compact as possible. A water-hammer preventing device C which has a single kind of valve-element biasing spring h is devised as shown in Fig. 7 and such valve-element biasing spring h is designed such that it provides the same water-hammer preventing function and pressure regulating function of the above-mentioned water-hammer preventing device B which comprises the water-hammer preventing spring c and the pressure regulating spring d. Space necessary for accommodating the springs c and d is compared hereinafter with the space necessary for accommodating the spring h by giving phisical data in conjunction with attached drawings Fig. 6 and Fig. 7. In Fig. 6 (a) and (b), the water-hammer preventing device B of the present invention is schematically shown while the water-hammer preventing device C having the valve-element biasing spring h is schematically shown in Fig. 7 (a) and (b). To explain the water-hammer preventing device B of this invention first, the water-hammer preventing spring c and the pressure regulating spring d take the positions as shown in Fig. 6 (a) at the time of mounting thereof, wherein the valve element a has the length l of 33 mm, the intermediate spring receptacle has the length m of 13.5 mm and the entire length L₁ of the springs c,d is set at 68.5 mm. When the maximum load is applied, the springs, c,d take the shrinked position as shown in Fig. 6 (b). In Fig. 6 (b), the length n of the water-hammer preventing spring c becomes 12.5 mm. Assuming that the spring constant k₁ of the water-hammer preventing spring c is 3.044 kgf/mm² and the spring constant k₂ of the pressure regulating spring d is 0.1177 kgf/mm², the maximum load F max = 3.044×(20.5 - 12.5)=24.352 kgf. In the formula, 20.5 mm is the length of the water-hammer preventing spring under no load. To obtain the above-mentioned maximum weight F max with the water-hammer preventing device C shown in Fig. 7 (a)(b), the entire length L₂ becomes as follows. Since the wire diameter of the pressure regulating spring d is too small, the maximum weight F max exceeds the allowable weight so that, in calculation of the maximum weight F max , although the spring constant K of the valve-element biasing spring h is set to be the spring constant k₁ of the pressure regulating spring d, the wire diameter and coil diameter of the valve-element biasing spring h are set to be those of the water-hammer preventing spring c. Assuming that L D = length at completely compressed position (Fig. 7 (b)), L S = length at the time of mounting (Fig. 7 (a)), wire diameter d of the valve-element biasing spring d=2.6 mm, coil diameter D of the valve-element biasing spring D = 17 mm, effective coil winding number N is N = GD⁴/8KD³ = 7000 × 2.6⁴/ 8×0.1177×17³ =69.15 . Accordingly, L D =(69.15+2) ×2.6 =184.99 mm Assuming L f as the spring length under no load and the pressure is regulated under 1 kgf/cm², following calculation can be made. (L F - L S ) ×0.1177=π (L F - L D ) ×0.1177=24.352 ∴ L S = L D -( π-24.352)/0.1177=362.5 mm Namely, L₂=35+ L S = 400.2 mm = 5.84 L₁ Namely, to carry out the water-hammer preventing function and the pressure regulating function with a single valve-element biasing spring h, such spring h must be approximately 6 times as long as the springs c,d of the present invention. As apparent from the above comparison and review, the water-hammer preventing device B, B′ can be made as compact as possible while possessing the sufficient water-hammer preventing function and pressure regulating function. Although the water-hammer preventing devices B, B′ are accomodated in the cold-water supply pipe 11 and the hot-water supply pipe 12, the devices B may be mounted in the valve body of the mixing valve 10. [Second Embodiment] The second embodiment is explained hereinafter in view of Fig. 8 to Fig. 16. In Fig. 8, the entire structure of a water stop valve M which can be mounted on the pipe located upstream of a faucet as described later is shown. The water stop valve M comprises, as shown in Fig. 9 to Fig. 13, a valve casing 103 which is provided with a water inlet port 101 and water outlet port 102 on the upper and side surfaces thereof respectively in a perpendicular relationship and within the valve casing 103, a water stop section C, a strainer section N and a water-hammer preventing section B″ are provided. The water stop section C has the construction shown in Fig. 9 and Fig. 10. A valve element guide 104 is threadedly mounted on the side wall of the valve casing 103 in such a manner that the axis there of is inclined relative to the horizontal. A water stop valve element 105 is threadedly engaged into the valve element guide 104 and is provided with a packing at the distal end thereof. By engaging an end of a driver into a slit on the proximal end of the water stop valve element 105 and turning the element 105, the element moves axially to make the packing 106 come into contact with a water stop valve seat 108 formed in the valve casing 103 or retract from the valve seat 108 thereby allowing or terminating the communication between the water inlet port 101 and the water outlet port 102. The construction of the strainer section N is shown in Fig. 9, Fig. 11 and Fig. 12. As shown in Fig. 9, the strainer section N is disposed in the valve casing 103 parallel to the water stop section C while being defined by a partition wall from the water stop section C. The strainer section N substantially comprises a filter 109 which is made of an approximately cylindrical metal mesh screen and the axis of the strainer is also inclined relative to the horizontal in the same manner as the valve element guide 104. Since the water stop section C is opened in the normal operating condition, water which enters the valve casing 103 flows as shown in a dotted line, namely, the water inlet port 101→ the water stop valve seat 108 →the filter 109 (from the outside into the inside) and the water is screened. The construction of the water-hammer preventing section B″ is shown in Fig. 10 to Fig. 13. The section B″ is disposed at the upper part of the valve casing 103 and has an axis thereof directed perpendicular to the axis of the water stop valve section C and the axis of the strainer section N. The water-hammer preventing section B″ substantially comprises a water-hammer preventing means mounting sleeve 110, a plunger-like valve element 111 axially reciprocably disposed in the sleeve 110 and a valve-element biasing means a applying a biasing force on the valve element 111 in a direction to open the valve element 111. The inside space defined in the water-hammer preventing means mounting sleeve 110 is communicated with the inside of the strainer N by way of an upstream passage 112. As shown in Fig. 11, the valve element 111 is provided with communicating passages 113 on the outer surface thereof circumferentially equidistantly ( the number of the passages 113 may be increased, for example, 6 ) and the above-mentioned upstream passage 112 is communicated with the right-side end of the communicating passages 113 and the left-side end of the communicating passages 113 is communicated with the water outlet port 102 by way of a downstream passage 114 and a throttling portion c′ is formed between the left-side end of the communicating passage 113 and the right-side end 113a of the downstream passage 113. Due to such construction, the water which enters into the strainer section N by way of the water inlet port 101 and the water stop valve seat 108 subsequently flows as shown in a dotted line, namely, the strainer section N →the upstream passage 112 →the communicating passage 113 →the downstream passage 114 and flows out from the valve casing 103 into an outside pipe not shown through the water outlet port 102. On the outer peripheral surface of the right-side portion of the valve element 111, a plurality of annular recesses are formed parallely spaced-apart manner in an axial direction and a wear-resistant ring 115, an O-ring 116 and a back-up ring 117 are mounted in the recesses whereby the deterioration of the wear resistance between the waterhammer preventing device mounting sleeve 110 and the valve element 111 can be reduced and the water leakage can effectively be prevented. The valve element biasing means a′ comprises a first spring 118, a second spring 119 which has a spring coefficient which is smaller than that of the first spring 118 and an intermediate spring receptacle 120 interposed between two springs 118, 119. The first spring 118 has one end thereof come into contact with the end surface of a plug 121 which is threadedly mounted on right-side end of the waterhammer preventing means mounting sleeve 110 and the other end received in the intermediate spring receptacle 120 to bias the receptacle 120 in a leftward direction. The second spring 119 has one end thereof received in and supported by the intermediate spring receptacle 120 and the other end come into contact with the valve element 111 to bias the valve element 111 in a leftward direction. Namely, the valve element 111 is biased in a leftward direction or in a direction to open the throttling portion c by means of a pair of first and second springs 118, 119 which are arranged in series. To be more specific, the respective ends of the second spring 119 are received in the recesses 122,123 which are formed in the intermediate spring receptacle 120 and the valve element 111. The plug 121 is provided with an air bleed port 124 which makes the movement of the valve element 111 smooth. The air bleed port 124 has the inside surface thereof formed into a conical-shaped recess and an air valve element 126 provided with an O-ring 125 on the outer surface thereof is accommodated into the recess. By the rightward movement of the air valve element 126, the air bleed port 124 is closed and the water leakeage therefrom can be prevented. Numeral 127 indicates a washer which guides the movement of the air valve element 126 and is provided with an air bleed aperture 128. Numerals 129,130 indicate dampening members which are accommodated in the left end of the valve element 111 and the right end of the intermediate spring receptacle 120. In the water-hammer preventing section B, the valve-element biasing force F₁ of the valve element biasing means a has a following characteristics. Namely, as shown in Fig. 14, the spring coefficient K of the valve element biasing means a is set in two stages, namely, K= k₁ · k₂/(k₁+k₂) until one end of the valve element 111 comes into contact with the corresponding end of the intermediate spring receptacle 120 while K =k₂ after one end of the valve element 111 comes into contact with the corresponding end of the intermediate spring receptacle 120. In the above formula, k₁ is the spring constant of the first spring 118 and k₂ is the spring constant of the second spring 119. The valve element biasing force is expressed by the following formula; F₂ =P₃ · Av+P₁ · (Ac - Av) . In the formula, P₁ is upstream pressure of upstream passage 112, P₂ is downstream pressure of downstream passage 114, Av is area of the left end surface 131 of the valve element 111 and Ac is cross-sectional area of the mounting sleeve 110. In Fig. 15, a water stop valve M having the above-mentioned construction is interposed between a spout 151 on a washing basin 150 and a water supply pipe 152. Numeral 153 indicates a handle for operating the spout 154, numeral 155 indicates a bowl and numeral 156 indicates a water drainage pipe. The flow regulating function and the water-hammer preventing function during water flowing operation by the above-mentioned waterhammer preventing section B″ will be explained hereinafter in view of Fig. 16. Assuming that the upstream pressure P₁ or the downstream pressure P₂ is elevated (or lowered) during the water flowing operation, the flow amount through the water stop valve increases (or decreases) and corresponding to such change of flow amount, the valve element 111 moves right (or left) and narrow (or widen) the opening area b of the throttling portion c′ and automatically regulate the flow amount of water from the water stop valve M. Since the wear ring 115 is interposed between the water-hammer preventing means mounting sleeve 110 and the valve element 111, surging which may tend to occur during water flowing operation is restricted for a long time. Furthermore, assuming that the water hammer is about to occur in the downstream passage 114 due to the sudden water stopping operation of the spout 151 by a user, the sharp pressure rise, namely, water-hammer is effectively absorbed by the displacement of the valve-element biasing means which corresponds to the movement of the valve element 111 and the increase of the space or volume of the downstream passage 114. Namely, when the water-hammer is about to occur, the pressure in the upstream passage 112 and the downstream passage 114 sharply increases. In this phenominon, since the waterhammer occurs in the downstream passage 114, the pressure P₂ is larger than the pressure P₁ and the area Av is larger than the area Ac. As apparent from the above-mentioned formula F₂=P₂·Av+P₁ · (Ac -Av) , the valve element biasing force F₂ is sharply increased and the valve element 111 is moved right. Accordingly, the opening area b′ of the throttling portion c′ is narrowed while the flow amount space or volume in the downstream passage 114 is increased corresponding to the valve-moved volume of the valve element 111 thus absorbing the pressure of waterhammer and the energy of the flow to restrict the adverse effect of the waterhammer to the upstream passage 112 and the water supply pipe 152. Furthermore, as described previously, in this embodiment, the spring constant K is set to vary in two stages corresponding to the stroke of the valve element 111. Accordingly, during the usual water flowing operation, the valve element 111 is biased with the small spring constant to smoothly regulate the flow amount of the spouting water and when the pressure of large magnitude such as waterhammer applies on the valve element 111, approximately at the stroke end of the valve element 111, the valve element biasing force F₁ generated by the larger spring constant k₁ copes with the valve element pressing force F₂ so that the full closing of the throttling portion c′ is prevented while preventing the intermediate spring receptacle 120 to bump into the plug 121. In this manner, the flow regulating function and the water-hammer preventing function are both achieved by the water stop valve of this embodiment. As has been described heretofore, the water stop valve can absorb the sharp pressure rise of water hammer and prevent the occurrence of the unusual or uncomfortable sound and the water leakage from the pipings such as the water supply pipe 152. Namely, since the water stop valve is provided with flow amount regulating function and the waterhammer preventing function, the water stop valve can be made considerably compact and the construction thereof is also considerably simplified. [Third Embodiment] The third embodiment is described in view of Fig. 17 to Fig. 24. Different from the water stop valve of the second embodiment which is provided with the water inlet port 101 and the water outlet port 102 on the upper and side surfaces of the valve casing 103, the water stop valve M′ of this embodiment is characterized in that an water inlet port 201 and water outlet port 202 are provided on the upper and lower surfaces of a valve casing 203. Due to such construction, the simple piping shown in Fig. 24 becomes possible. However, since the inner structure of the valve casing 203 and the function of the water stop valve M′ is substantially the same as those of the water stop valve M of the second embodiment, like parts are denoted by the same numerals further added with 100. Furthermore, different from the second embodiment, the axis of the water stop section C and the axis of the strainer N are not inclined but horizontal , the inner structure of the valve casing 203 can be considerably simplified and can be produced at much inexpensive cost compared to the water stop valve of the second embodiment.

Claims: Device for preventing water hammer while regulating water pressure comprising : a) a communicating passage (25) formed in a valve casing (23) to communicate an upstream passage (R₁) with a downstream passage (R₂), b) a valve element (a) being reciprocable in the valve casing (23) to open or close the communicating passage (25), and c) a valve element biasing means (b) biasing said valve element (a) characterized in that said valve element biasing means (b) biases said valve element (a) in an opening direction, and comprise a pressure adjusting spring (d) having a small spring constant and a water-hammer preventing spring (c) having a large spring constant whereby said springs (c,d) are disposed in series in said valve casing (23), said valve element biasing means (b) capable of varying the opening area of said communicating passage (25) so as to adjust the pressure in said communicating passage (25) while preventing the occurrence of water hammer. Device for preventing water hammer while regulating water pressure according the Claim 1, further comprising an auxiliary passage (e) capable of flowing out an amount of water which corresponds to a valve-moved volume from said upstream (R₁ ) passage to said downstream passage (R₂) corresponding to the movement of said valve element (a) in closing direction at the time of the occurrence of water hammer. Device for preventing water hammer while regulating water pressure according to claim 1 or 2, wherein said valve element biasing means (b) is capable of reciprocating said valve element (a) almost only coupled with a downstream-side valve pressing pressure which occurs in said downstream passage(R₂). Device for preventing water hammer while regulating water pressure according to one of preceding claims, wherein said device is accommodated in a water-supply tube (20) which has one end connected to a mixing valve (10) for mixing hot water and cold water. Device for preventing water hammer while regulating water pressure according to one of preceding claims, wherein said device is accommodated in a mixing valve (10) for mixing hot water and cold water. Device for preventing water hammer while regulating water pressure according to one of preceding claims, wherein said device is accommodated in a water stop valve (M).

Inventors: FUJISHIMA, YUKIHIRO, KIMURA, YASUHIDE, MOTOHASHI, TAKESHI
Applicants: TOTO LTD.
Application year: 1989
Main classification: F16K47
IPC codes: F16K47, F16L55