Abstract:
A control valve with a planar seal structure having a valve body with a water inlet, water outlet, and water drainage port. A spool with a planar seal structure and having fixed valve plate and movable valve plate is disposed in the valve body. The movable valve plate is rotationally fitted to the fixed valve plate. The fixed valve plate has a plurality of through-holes. One through-hole with an arc and fan shape is in communication with the water outlet. The outer diameter of the through-hole with an arc and fan shape is greater than that of another through-hole of the fixed valve plate. The through-hole is in communication with the valve body&#39;s water inlet. The fixed valve plate has at least one arc communicating blind hole. The through-holes of the fixed valve plate are mutually fitted with the communicating blind hole.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to the field of water treatment system, especially for the control valve that adopting hermetic head faces construction. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    In recent years, with the wider application of the control valve with hermetic head faces construction in water treatment field, the market has approved the structure of flat valve. Nowadays, industrial or residential water treatment systems must use control valve to switch channel For the control valve of softener system, it should achieve softening, backwash, brine draw, brine refill and fast rinse these functions; for control valve of filter system, it should achieve filtration, backwash and fast rinse these functions. For illustration purposes, the backwash, brine draw, brine refill and fast rinse of softener system are collectively called as regeneration process; the backwash and fast rinse of filter system are collectively called as rinse process. 
         [0003]    For industrial fields, especially for the water treatment system that is applied to steam boiler, the hardness of water should be no more than 0.03 mmol/L when it goes into the boiler. Therefore, it often requires that there is no raw water flows into the boiler when the control valve in the regeneration process of the water treatment system. Thus, the existing flat valves on the market are with this structure basically, namely there is no water flows out when in regeneration process. For hot water boilers, the requirement of inlet water hardness is lower, not higher than 0.6 mmol/L. the regeneration process of water treatment system generally takes more than two hours, rinse process usually takes 30 minutes. For the water treatment system that no water flows out from outlet when in the regeneration process, to ensure an adequate water supply to the rear systems during the regeneration or rinse process, it requires the larger water tank. 
         [0004]    For residential water treatment systems, especially for household water treatment systems, the requirement of inlet water is lower. The residential water treatment systems generally are without the water tank, which leads to no water supply when need water urgently when in regeneration or rinse process. Therefore, in the market of North America and Europe, the household water treatment systems can provide the raw water when in regeneration or rinse process. The raw water described in this article refers to untreated water. 
         [0005]    Existing water treatment control valve adopts hermetic head faces construction. Such as Chinese patent CN201305482Y Multi-functional Softener Valve, CN201305482Y Multi-functional Softener Valve, which provides a kind of control valve that sets the fixed disk to three layers—the outermost layer is outlet; The moving disk only matches to fixed disk in service status, and in other status, the moving disk can not cover the outlet completely. This structure makes the valve body with complicated structure, moving disk and fixed disk complicated, and makes trouble. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides a control valve to overcome the deficiency of no raw water flowing out when the existing flat valve in regeneration or rinse process, and it is applicable to all of softener systems and filter systems. 
         [0007]    To achieve the above objects, the present invention provides a control valve that adopts hermetic head faces construction, which includes valve body, moving disk and fixed disk that are rotating in the sealing surface to match with each other. The described valve body is provided with inlet, outlet and drain. There are many through-holes in described fixed disk. Among them, one through-hole is connected to outlet, the outer diameter of which is bigger than other through-holes and forms an arc-shaped bulge that is from center to circumferential direction. There is one through-hole at least of moving disk connected to inlet, and has a through blind hole with an arc-shaped bulge from center to circumferential direction. The outer diameter of this through blind hole is bigger than the outer diameter of described inlet. The arc-shaped bulges of fixed disk and moving disk are overlapped to match with each other when valve in softener or filter status. 
         [0008]    In use, when the control valve is in softener or filter status, the through-hole of moving disk is connected to inlet all the time, the arc-shaped bulge of through blind hole in moving disk and the one in fixed disk overlap and match with each other. When the control valve is in regeneration or rinse status, the through-hole of moving disk is connected to inlet all the time, the arc-shaped bulge of through blind hole in moving disk and the one in fixed disk overlap incompletely. At that time, a part of water from inlet flows through this incompletely overlapped part into the through-hole of fixed disk that connected to outlet Finally, the water flows out from outlet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a top view of one kind of fixed disk for the control valve that is no water flows out in regeneration status; 
           [0010]      FIG. 2  is a top view of one kind of moving disk that matching with  FIG. 1 ; 
           [0011]      FIG. 2A  is a cross-sectional view of  FIG. 2 ; 
           [0012]      FIG. 3  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 1  and  FIG. 2 ; 
           [0013]      FIG. 4  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 1  and  FIG. 2 ; 
           [0014]      FIG. 5  is a top view of another kind of fixed disk for the control valve that is no water flows out in regeneration status; 
           [0015]      FIG. 6  is a top view of one kind of moving disk that matching with  FIG. 5 ; 
           [0016]      FIG. 6A  is a cross-sectional view of  FIG. 6 ; 
           [0017]      FIG. 7  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 5  and  FIG. 6 ; 
           [0018]      FIG. 8  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 5  and  FIG. 6 ; 
           [0019]      FIG. 9  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to six equal parts) 
           [0020]      FIG. 9A  is a cross-sectional view of  FIG. 9 ; 
           [0021]      FIG. 10  is a top view of another kind of fixed disk for the control valve that raw water flows out in regeneration status; 
           [0022]      FIG. 10A  is a cross-sectional view of  FIG. 10 ; 
           [0023]      FIG. 11  is a top view of one kind of moving disk that matching with  FIG. 9  or  FIG. 10 ; 
           [0024]      FIG. 11A  is a cross-sectional view of  FIG. 11 ; 
           [0025]      FIG. 12  is a top view of another kind of moving disk that matching with  FIG. 9  or  FIG. 10 ; 
           [0026]      FIG. 12A  is a cross-sectional view of  FIG. 12 ; 
           [0027]      FIG. 13  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 9  and  FIG. 12 ; 
           [0028]      FIG. 14  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 9  and  FIG. 12 ; 
           [0029]      FIG. 15  is a top view of one kind of fixed disk for the control valve that raw water flows out in rinse status in filter system; (The surface of fixed disk is divided to six equal parts) 
           [0030]      FIG. 15A  is a cross-sectional view of  FIG. 15 ; 
           [0031]      FIG. 16  is a top view of one kind of moving disk that matching with  FIG. 15 ; 
           [0032]      FIG. 16A  is a cross-sectional view of  FIG. 16 ; 
           [0033]      FIG. 17  is a combinatorial drawing of the moving disk and fixed disk when the system in filter status that composed of  FIG. 15  and  FIG. 16 ; 
           [0034]      FIG. 18  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 15  and  FIG. 16 ; 
           [0035]      FIG. 19  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to seven equal parts) 
           [0036]      FIG. 20  is a top view of one kind of moving disk that matching with  FIG. 19 ; 
           [0037]      FIG. 21  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 19  and  FIG. 20 ; 
           [0038]      FIG. 22  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 19  and  FIG. 20 ; 
           [0039]      FIG. 23  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to eight equal parts) 
           [0040]      FIG. 23A  is a cross-sectional view of  FIG. 23 ; 
           [0041]      FIG. 24  is a top view of one kind of moving disk that matching with  FIG. 23 ; 
           [0042]      FIG. 24A  is a cross-sectional view of  FIG. 24 ; 
           [0043]      FIG. 25  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 23  and  FIG. 24 ; 
           [0044]      FIG. 26  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 23  and  FIG. 24 ; 
           [0045]      FIG. 27  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to eight equal parts) 
           [0046]      FIG. 28  is a top view of one kind of moving disk that matching with  FIG. 27 ; 
           [0047]      FIG. 28A  is a cross-sectional view of  FIG. 28 ; 
           [0048]      FIG. 29  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 27  and  FIG. 28 ; 
           [0049]      FIG. 30  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 27  and  FIG. 28 ; 
           [0050]      FIG. 31  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to nine equal parts) 
           [0051]      FIG. 32  is a top view of one kind of moving disk that matching with  FIG. 30 ; 
           [0052]      FIG. 32A  is a cross-sectional view of  FIG. 32 ; 
           [0053]      FIG. 33  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 31  and  FIG. 32 ; 
           [0054]      FIG. 34  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 31  and  FIG. 32 ; 
           [0055]      FIG. 35  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to nine equal parts) 
           [0056]      FIG. 36  is a top view of one kind of moving disk that matching with  FIG. 35 ; 
           [0057]      FIG. 36A  is a cross-sectional view of  FIG. 36 ; 
           [0058]      FIG. 37  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 35  and  FIG. 36 ; 
           [0059]      FIG. 38  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 35  and  FIG. 36 ; 
           [0060]      FIG. 39  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to ten equal parts) 
           [0061]      FIG. 40  is a top view of one kind of moving disk that matching with  FIG. 39 ; 
           [0062]      FIG. 41  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 39  and  FIG. 40 ; 
           [0063]      FIG. 42  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 39  and  FIG. 40 ; 
           [0064]      FIG. 43  is a top view of one kind of fixed disk for the control valve that raw water flows out in regeneration status; (The surface of fixed disk is divided to ten equal parts) 
           [0065]      FIG. 44  is a top view of one kind of moving disk that matching with  FIG. 43 ; 
           [0066]      FIG. 45  is a combinatorial drawing of the moving disk and fixed disk when the system in service status that composed of  FIG. 43  and  FIG. 44 ; 
           [0067]      FIG. 46  is a combinatorial drawing of the moving disk and fixed disk when the system in backwash status that composed of  FIG. 43  and  FIG. 44 ; 
           [0068]      FIG. 47  is a structure schematic view of this invention that is in softening water status in  FIG. 25 ; 
           [0069]      FIG. 48  is a structure schematic view of this invention that is in backwash status in  FIG. 26 ; 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0070]    Existing control valve with hermetic head faces construction that has a variety of matching ways of moving disk and fixed disk. In the fixed disk, there has set different numbers of holes that in cooperation with the moving disk. And the layouts of the holes are five equal parts, six equal parts, seven equal parts, eight equal parts, nine equal parts, ten equal parts, eleven equal parts and twelve equal parts, etc. Sometimes, the holes are set not in equal parts. Some moving disks have a through-hole and a through blind hole, and some moving disks have many through-holes and many through blind holes. 
         [0071]    Control valve of the present invention can be used to softener system, also can be used to filter system. When used to softener system, the valve body is provided with inlet, outlet, drain and brine inlet, injector inlet and injector outlet, and nozzle of injector. When used to filter system, the valve body is provided with inlet, outlet and drain. 
         [0072]    It is the structure shown in  FIG. 1  to  FIG. 4  that no raw water flows out in the existing water treatment regeneration process, which has described in Patent CN2719820Y Multi-functional Flow Control Valve for Water Treatment System, and it is unnecessary to go into details here. 
         [0073]    It is another structure shown in  FIG. 5  to  FIG. 8  that no raw water flows out in the existing water treatment regeneration process. 
       EXAMPLE 1 
       [0074]    It is the project shown in  FIG. 9  to  FIG. 14  that refilling with soft water and raw water flowing out when in regeneration status for the up-flow regeneration softener valve, which has the fixed disk with six equal parts structure. 
         [0075]    This example uses fixed disk and moving disk shown in  FIG. 10  and  FIG. 11 . The valve body of the multi-functional softener valve in this example is provided with inlet  20 , outlet  21 , drain  22 , upper filter connector  16 , lower filter connector  17  and branch of flow channel  26 . On branch of flow channel, there is the injector inlet  24 , injector outlet  25  that connected to the lower filter connector  17 , brine inlet  23  and brine control valve  5  connected to brine inlet  23 . In valve body  1 , there is fixed disk  3 , moving disk  4 , seal ring  6  and the shaft  2  that can rotate the moving disk  4 . There is the sixth through-hole  36  connected to drain  22  of valve body in the center of fixed disk  3 . In the outer rotating radius, there are five through-holes. Among them, the first through-hole  31  and the second through-hole  32  are connected to upper filter connector  16 , the third through-hole  33  is connected to the lower filter connector  17 , and the fourth through-hole  35  is connected to outlet  21 . The outer diameter of through-hole  35  is bigger than other through-holes and the edge of the sealing surface. The fifth through-hole  37  is connected to injector inlet  24  by branch of flow channel  26 . There is a through-hole  41  connecting to inlet  20  all the time, a radial through blind hole  43  that is from center to circumferential direction, and an arc-shaped blind hole  42  that round the central in the sealing surface of moving disk  4 . A part of outer diameter of through blind hole  42  is bigger than other edges of the sealing surface and as big as the outer diameter of through-hole  34 . The through-holes of fixed disk  3  and moving disk  4  are matching in the same rotating radius. In production, fixed disk  3  and moving disk  4  adopt different materials such as ceramic. The through-hole  31  and  32  of fixed disk can be connected to be one through-hole, but it is inconvenient to process. 
         [0076]    Such designed softener valve has the following advantages: 1, Brine draw for regeneration and brine refill can be controlled by brine control valve  5  that only require a small flow, and the disk can be divided in six equal parts, which can increase the flow rate. 2, Brine refill can be controlled by procedure or brine control valve  5  manually when it needs. For the softener valve of residential softener, it can achieve brine refill after service, in service, or any other time when it needs, which has a wider range of applications. At the same time, it can save regeneration time. 3, Controlling by brine control valve  5 , the brine tank can be refilled with soft water, which will enhance a better regeneration effect of resin. 4, This example adopts up-flow regeneration, which can enhance the regeneration effect of resin and save salt and water. 5, When it in backwash, regeneration and fast rinse, part of raw water can flow out from outlet directly, which can provide the emergency water when in regeneration process. 
         [0077]    As shown  FIG. 10 , the outer diameter of the through-hole  35  is bigger than other through-hole and the edge of sealing surface; the part of outer diameter of blind hole  42  is bigger than the edge of other sealing surface and as big as the outer diameter of through-hole  35 . The following illustration is only about the backwash status, and the other four functions are no longer specified 
         [0078]    Backwash status: Referring to  FIG. 47  and  FIG. 48 , by rotating the shaft  2 , the through-hole  41  of moving disk  4  and the third through-hole  33  of fixed disk  3  overlap, the through blind hole  43  is connected to the first through-hole  31  and the sixth through-hole  36 , the through blind hole  42  is only connected to the fourth through-hole  35 , and the brine control valve  5  is closed. Because the outer diameter of the fourth through-hole  35  is bigger, the sealing surface of moving disk  4  covers it incompletely. At that time, a part of water flows from the inlet  20  into the through-hole  41  and then flows into the third through-hole  33 , through valve body  1  to the lower filter connector  17 , through the bottom strainer  12  to tank  10 , flows through and rinses filter element  13 , and the dirt goes through top strainer  11  to the upper filter connector  16 , then goes through the first through-hole  31  and blind hole  43  to the sixth through-hole  36 . Due to the connection of the sixth through-hole  36  and drain  22 , the water flows out from drain  22 ; the other part of water flows from inlet  20  into the fourth through-hole  35 , and then flows out from outlet  21  directly. At that time, the blind hole  42  is only connected to the fourth through-hole  35 , and no water flows. 
       EXAMPLE 2 
       [0079]      FIG. 15  to  FIG. 18  are the schematic views of moving disk and fixed disk that for filter pipe device of the water purifier shown in patent CN2573049Y that adds the function of flowing out raw water, and the matching schematic views of moving disk relative to fixed disk in filter and backwash status. 
       EXAMPLE 3 
       [0080]      FIG. 19  to  FIG. 22  are the schematic views of moving disk being provided with one through-hole and two through blind holes when the fixed disk is divided to seven equal parts, and the matching schematic views of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 4 
       [0081]      FIG. 23  to  FIG. 26  are the schematic views of moving disk being provided with two through-holes and one through blind hole when the fixed disk is divided to eight equal parts, and the matching schematic views of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 5 
       [0082]      FIG. 27  to  FIG. 30  are the schematic views of moving disk being provided with one through-hole and two through blind holes when the fixed disk is divided to eight equal parts, and the matching schematic view of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 6 
       [0083]      FIG. 31  to  FIG. 34  are the schematic views of moving disk being provided with two through-holes and one through blind hole when the fixed disk is divided to nine equal parts, and the matching schematic view of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 7 
       [0084]      FIG. 35  to  FIG. 38  are the schematic views of moving disk being provided with one through-hole and two through blind holes when the fixed disk is divided to nine equal parts, and the matching schematic view of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 8 
       [0085]      FIG. 39  to  FIG. 42  are the schematic views of moving disk being provided with one through-hole and two through blind holes when the fixed disk is divided to ten equal parts, and the matching schematic view of moving disk relative to fixed disk in service and backwash status. 
       EXAMPLE 9 
       [0086]      FIG. 43  to  FIG. 46  are the schematic views of moving disk being provided with two through-holes and one through blind hole when the fixed disk is divided to ten equal parts, and the matching schematic view of moving disk relative to fixed disk in service and backwash status. 
         [0087]    Referring to FIG. 1  to  FIG. 46 , in the fixed disk, the through-hole  31  and through-hole  32  are all connected to upper filter connector, through-hole  33  and through-hole  34  are all connected to lower filter connector, through-hole  35  is connected to outlet, through-hole  36  is connected to drain, through-hole  37  is connected to injector inlet, and through-hole  38  is connected to injector outlet; in the moving disk  4 , through-hole  41  is connected to inlet of valve body all the time,  42  and  43  are all through blind holes, and through-hole  44  is connected to drain of valve body. 
         [0088]    The illustration is only about down-flow softener that used to softener system. For filter system, it is no longer specified because it is similar as using to softener system. The following illustration is about fixed disk divided to eight equal parts and moving disk with one through-hole and two through blind holes. 
         [0089]    Referring to  FIG. 23  to  FIG. 26 ,  FIG. 47  and  FIG. 48 , the valve body  1  is provided with inlet  20 , outlet  21 , drain  22 , brine inlet  23 , and flow channels connected to top strainer  11  and bottom strainer  12  respectively. There is the branch of flow channel  26  in the channel from inlet  20  of valve body  1  to tank. This branch of flow channel  26  is provided with a nozzle of injector, and there is brine inlet  23  in the outlet of nozzle, which is connected to brine tank  14 . Fixed disk  3  is set in the valve body  1 , and achieves the matching of with moving disk  4  by rotating shaft  2 . The fixed disk  3  of valve body  1  has many through-holes. Among them, the through-hole  35  is connected to outlet  21 , the outer diameter of which matching with moving disk  4  is bigger than other through-holes and form an arc-shaped bulge that is from center to circumferential direction. The described fixed disk  4  matches with moving disk  3 , and at least one through-hole  41  is connected to inlet  20  of valve body all the time. There is an arc-shaped blind hole  42  that has an arc-shaped bulge from center to circumferential direction at the place of matching with fixed disk. The outer diameter of arc-shaped blind hole is bigger than described inlet through-hole. And the arc-shaped bulge of fixed disk matches the one of moving disk. 
         [0090]    Referring to  FIG. 25  and  FIG. 47 , during normal service of softening, the through-hole  31  of fixed disk  3  is connected to through blind hole  41  of moving disk  4 , the other through-holes of fixed disk  3  and the other through-holes or through blind holes of moving disk  4  are one-to-one match, which forms the flow direction shown as  FIG. 45 , namely, raw water flows into inlet  20 , flows through through-hole  41  of moving disk  4 , flows through fixed disk  3 , valve body  1  and then into top strainer  11 . After treated by filter element  13 , flows into bottom strainer  12 , turns back to through-hole  33  of fixed disk  3  through riser pipe, flows through the arc-shaped blind hole  42  of moving disk  4 , goes into through-hole  35  of fixed disk  3 . Finally, it goes out from outlet  21 . 
         [0091]    Referring to  FIG. 26  and  FIG. 48 , during backwash, the through-hole  31  of fixed disk  3  and the through blind hole  41  of moving disk  4  are overlapped incompletely or not overlapped completely, the other through-holes of fixed disk  3  and the other through-holes or through blind holes of moving disk  4  are one-to-one match, which forms the flow direction shown as  FIG. 46 , namely, raw water flows into inlet  20 , flows through through-hole  41  of moving disk  4 , through fixed disk  3  and valve body  1  and then into bottom strainer  12  through riser pipe. After backwashing the filter element  13 , flows into top strainer  11 , finally turns back to through-hole  43  of fixed disk  3 , flows through the blind hole  43  of moving disk  4 , goes into through-hole  36  of fixed disk  3 . Finally, it goes out from drain  22 . The other part of raw water flows into the through-hole  35  directly that is overlapped incompletely, and then flows out from outlet  21 . 
         [0092]    When adopting the fixed disk and moving disk shown as  FIG. 9  and  FIG. 11  or  FIG. 12 ,  FIG. 10  and  FIG. 11  or  FIG. 12 ,  FIG. 15  and  FIG. 16 ,  FIG. 19  and  FIG. 20 ,  FIG. 27  and  FIG. 28 ,  FIG. 31  and  FIG. 32 ,  FIG. 35  and  FIG. 36 ,  FIG. 39  and  FIG. 40 ,  FIG. 43  and  FIG. 44 , which can respectively forms the matching schematic views of moving disk relative to fixed disk in service and backwash status shown as  FIG. 11  and  FIG. 12 ,  FIG. 15  and  FIG. 16 ,  FIG. 19  and  FIG. 20 ,  FIG. 27  and  FIG. 28 ,  FIG. 31  and  FIG. 32 ,  FIG. 35  and  FIG. 36 ,  FIG. 39  and  FIG. 40 ,  FIG. 43  and  FIG. 44 . And the flow direction is similar as  FIG. 47  and  FIG. 48 , which is unnecessary to go into details here.