INTERSTATE STANDARD
UNIFIED SYSTEM OF DESIGN DOCUMENTATION
CONDITIONAL GRAPHIC NOTATIONS.
HYDRAULIC AND PNEUMATIC MACHINES
GOST 2.782-96
INTERSTATE COUNCIL FOR STANDARDIZATION,
METROLOGY AND CERTIFICATION
PREFACE.
1. DEVELOPED by the Research and Design Institute of Industrial Hydraulic Drives and Hydraulic Automatics (NIIGidroprivod), the All-Russian Research Institute of Standardization and Certification in Mechanical Engineering (VNIINMASH). INTRODUCED by the State Standard of Russia.2. ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 10 of October 4, 1996). The following voted for adoption:
|
State name |
Name of the national standardization body |
| The Republic of Azerbaijan | Azgosstandart |
| Republic of Armenia | Armgosstandard |
| Republic of Belarus | Belstandart |
| The Republic of Kazakhstan | Gosstandart of the Republic of Kazakhstan |
| Kyrgyz Republic | Kyrgyzstandard |
| The Republic of Moldova | Moldovastandard |
| Russian Federation | Gosstandart of Russia |
| The Republic of Tajikistan | Tajik State Center for Standardization, Metrology and Certification |
| Turkmenistan | Turkmen State Inspectorate |
| Ukraine | State Standard of Ukraine |
1 area of use. 2 2. Normative references. 2 3. Definitions. 2 4. Basic provisions. 2 Appendix A Rules for indicating the dependence of the direction of rotation on the direction of flow of the working medium and the position of the control device for hydraulic and pneumatic machines. 8 Appendix B Examples of designation of the dependence of the direction of rotation on the direction of flow of the working medium and the positions of the control device for hydraulic and pneumatic machines. 8
GOST 2.782-96
INTERSTATE STANDARD
|
Unified system of design documentation. CONDITIONAL GRAPHIC NOTATIONS. HYDRAULIC AND PNEUMATIC MACHINES. Unified system for design documentation. |
Date of introduction 1998-01-01
1 AREA OF USE.
This standard establishes conventional graphic symbols of hydraulic and pneumatic machines (pumps, compressors, motors, cylinders, rotary motors, converters, displacers) in diagrams and drawings of all industries.2. REGULATORY REFERENCES.
This standard uses references to the following standards: GOST 17398-72 Pumps. Terms and Definitions. GOST 17752-81 Volumetric hydraulic drive and pneumatic drive. Terms and definitions. GOST 28567-90 Compressors. Terms and Definitions.3. DEFINITIONS.
This standard uses terms according to GOST 17752, GOST 17398 and GOST 28567.4. BASIC PROVISIONS.
4.1. The designations reflect the purpose (action), method of operation of the devices and external connections.4.2. The designations do not indicate the actual design of the device.4.3. The letters used in the designations represent only letter designations and do not give an idea of the parameters or parameter values.4.4. Unless otherwise stated, symbols may be drawn in any arrangement as long as their meaning is not distorted.4.5. The standard does not establish the dimensions of symbols. 4.6. Designations based on functional characteristics must correspond to those given in Table 1. If it is necessary to reflect the principle of operation, then the designations given in Table 2.4.7 are used. Rules and examples of designations for the relationship between the direction of rotation, the direction of flow of the working fluid and the position of the control device for pumps and motors are given in Appendices A and B.Table 1
|
Name |
Designation |
| 1. Non-regulated pump: - with non-reversible flow | |
| - with reverse flow | |
| 2. Adjustable pump: - with non-reversible flow | |
| - with reverse flow | |
| 3. Adjustable pump with manual control and one direction of rotation |
|
| 4. Pressure-regulated pump with one direction of rotation, adjustable spring and drain (see appendices A and B) |
|
| 5. Metering pump | |
| 6. Multi-outlet pump (for example, a three-outlet adjustable pump with one plugged outlet) |
|
| 7. Unregulated hydraulic motor: - with irreversible flow | |
| - with reverse flow | |
| 8. Hydraulic motor adjustable: - non-reversible flow, indefinite control mechanism, external drainage, one direction of rotation and two shaft ends |
|
| 9. Rotary hydraulic motor | |
| 10. Compressor | |
| 11. Unregulated pneumatic motor: - with irreversible flow | |
| - with reverse flow | |
| 12. Adjustable air motor: - with non-reversible flow | |
| - with reverse flow | |
| 13. Rotary air motor | |
| 14. Unregulated pump-motor: - with the same flow direction | |
| - with any flow direction | |
| 15. Pump-motor adjustable: - with the same flow direction | |
| - with reverse flow direction | |
| - with any direction of flow, with manual control, external drainage and two directions of rotation |
|
| 16. The pump-motor is adjustable, with two directions of rotation, spring centering of the displacement zero, external control and drainage (signal n causes movement in the direction N) (see appendices A and B) |
|
| 17. Volumetric hydraulic transmission: - with an unregulated pump and motor, with one direction of flow and one direction of rotation |
|
| - with adjustable pump, with reversible flow, with two directions of rotation with variable speed |
|
| - with a non-regulated pump and one direction of rotation |
|
| 18. Single-acting cylinder: - piston without specifying the method of rod return, pneumatic |
|
| - piston with spring return, pneumatic |
|
| - piston with spring rod extension, hydraulic |
|
| - plunger | |
| - telescopic with one-sided extension, pneumatic |
|
|
|
|
| 19. Double-acting cylinder: - with one-way rod, hydraulic |
|
| - with double-sided rod, pneumatic |
|
| - telescopic with one-way extension, hydraulic |
|
| - telescopic with two-way extension |
|
| 20. Differential cylinder (the ratio of the piston areas from the rod and non-rod cavities is of paramount importance) |
|
| 21. Double-acting cylinder with supply of working fluid through the rod: - with one-sided rod |
|
| - with double-sided rod |
|
| 22. Double-acting cylinder with constant braking at the end of the stroke: - on the piston side |
|
| - on both sides |
|
| 23. Double-acting cylinder with adjustable end-stroke braking: - piston side |
|
| - on both sides and an area ratio of 2:1 Note – If necessary, the ratio of the annular area of the piston to the area of the piston (area ratio) can be given above the piston designation |
|
| 24. Double-chamber, double-acting cylinder |
|
| 25. Diaphragm cylinder: - single-acting | |
| - double acting | |
| 26. Pneumohydraulic displacer with separator: - translational | |
| - rotational |
|
| 27. Translational converter: - with one type of working medium | |
| 28. Rotary converter: - with one type of working medium |
|
| - with two types of working environment |
|
| 29. Cylinder with built-in mechanical locks |
|
table 2
|
Name |
Designation |
|
1. Hand pump |
|
|
2. Gear pump |
|
|
3. Screw pump |
|
|
4. Vane pump |
|
|
5. Radial piston pump |
|
|
6. Axial piston pump |
|
|
7. Crank pump |
|
|
8. Centrifugal vane pump |
|
|
9. Jet pump: General designation |
|
|
With liquid external flow |
|
|
With external gas flow |
|
|
10. Fan: Centrifugal |
|
APPENDIX A
(recommended)
RULES FOR INDICATING THE DEPENDENCE OF THE DIRECTION OF ROTATION ON THE DIRECTION OF WORKING MEDIUM FLOW AND THE POSITION OF THE CONTROL DEVICE FOR HYDRAULIC AND PNEUMATIC MACHINES.
A.1. The direction of shaft rotation is indicated by a concentric arrow around the main designation of the machine from the power input element to the power output element. For devices with two directions of rotation, only one randomly selected direction is shown. For double shaft devices, the direction is shown at one end of the shaft.A.2. For pumps, the arrow begins at the drive shaft and ends with a point at the outlet flow line.A.3. For motors, the arrow begins at the input flow line and ends with the tip of the arrow at the output shaft.A.4. For pump-motors according to A.2 and A.3.A.5. If necessary, the corresponding position designation of the control device is shown near the tip of the concentric arrow.A.6. If the control characteristics are different for the two directions of rotation, information is shown for both directions.A.7. Line showing control device positions and position designations (e.g. M - Æ - N) are applied perpendicular to the control arrow. The sign Æ indicates the position of zero displacement, the letters M and N indicate the extreme positions of the control device for the maximum displacement. It is preferable to use the same symbols that are marked on the body of the device. The point of intersection of the arrow indicating regulation and perpendicular to the line indicates the “in stock” position (Figure 1). 
Picture 1.
APPENDIX B
(recommended)
EXAMPLES OF INDICATING THE DEPENDENCE OF THE DIRECTION OF ROTATION ON THE DIRECTION OF WORKING MEDIUM FLOW AND POSITIONS OF THE CONTROL DEVICE FOR HYDRAULIC AND PNEUMATIC MACHINES.
Table B.1
|
Name |
Designation |
| 1. Single-function device (motor). The hydraulic motor is unregulated, with one direction of rotation. | |
| 2. Single-function device (machine). The hydraulic machine is unregulated, with two directions of rotation. One direction of rotation is shown, related to the direction of flow. |
|
| 3. Single-function device (pump). The hydraulic pump is adjustable (with a change in working volume in one line), with one direction of rotation. The control device position designation may be omitted and is shown in the illustration for clarity only. |
|
| 4. Single-function device (motor). The hydraulic motor is adjustable (with displacement changing in one direction), with two directions of rotation. One direction of rotation is shown, related to the direction of flow. |
|
| 5. Single-function device (machine). The hydraulic machine is adjustable (with a change in working volume in both directions), with one direction of rotation. The direction of rotation and the corresponding position of the control device related to the direction of flow are shown. |
|
| 6. Single-function device (machine). The hydraulic machine is adjustable (with a change in working volume in both directions), with two directions of rotation. Shown is one direction of rotation and the corresponding position of the control device associated with the direction of flow. |
|
| 7. Pump-motor. The pump-motor is unregulated with two directions of rotation. | |
| 8. Pump-motor. The pump-motor is adjustable (with displacement changing in one direction), with two directions of rotation. One direction of rotation is shown, related to the direction of flow, when operating in pump mode. |
|
| 9. Pump-motor. The pump-motor is adjustable (with displacement changing in both directions), with one direction of rotation. The direction of rotation and the corresponding position of the control device associated with the direction of flow are shown when operating in pump mode. |
|
| 10. Pump-motor. The pump-motor is adjustable (using displacement in both directions, with two directions of rotation. One direction of rotation and the corresponding position of the control device associated with the direction of flow are shown when operating in pump mode. |
|
| 11. Motor. Motor with two directions of rotation: adjustable (with a change in displacement in one line) in one direction of rotation, unregulated in the other direction of rotation. Both possibilities are shown. |
INTERSTATE STANDARD
UNIFIED SYSTEM OF DESIGN DOCUMENTATION
CONDITIONAL GRAPHIC NOTATIONS.
HYDRAULIC AND PNEUMATIC MACHINES
GOST 2.782-96
INTERSTATE COUNCIL FOR STANDARDIZATION,
METROLOGY AND CERTIFICATION
PREFACE.
1. DEVELOPED by the Research and Design Institute of Industrial Hydraulic Drives and Hydraulic Automatics (NIIGidroprivod), the All-Russian Research Institute of Standardization and Certification in Mechanical Engineering (VNIINMASH). INTRODUCED by the State Standard of Russia.2. ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 10 of October 4, 1996). The following voted for adoption:
|
State name |
Name of the national standardization body |
| The Republic of Azerbaijan | Azgosstandart |
| Republic of Armenia | Armgosstandard |
| Republic of Belarus | Belstandart |
| The Republic of Kazakhstan | Gosstandart of the Republic of Kazakhstan |
| Kyrgyz Republic | Kyrgyzstandard |
| The Republic of Moldova | Moldovastandard |
| Russian Federation | Gosstandart of Russia |
| The Republic of Tajikistan | Tajik State Center for Standardization, Metrology and Certification |
| Turkmenistan | Turkmen State Inspectorate |
| Ukraine | State Standard of Ukraine |
1 area of use. 2 2. Normative references. 2 3. Definitions. 2 4. Basic provisions. 2 Appendix A Rules for indicating the dependence of the direction of rotation on the direction of flow of the working medium and the position of the control device for hydraulic and pneumatic machines. 8 Appendix B Examples of designation of the dependence of the direction of rotation on the direction of flow of the working medium and the positions of the control device for hydraulic and pneumatic machines. 8
GOST 2.782-96
INTERSTATE STANDARD
|
Unified system of design documentation. CONDITIONAL GRAPHIC NOTATIONS. HYDRAULIC AND PNEUMATIC MACHINES. Unified system for design documentation. |
Date of introduction 1998-01-01
1 AREA OF USE.
This standard establishes conventional graphic symbols of hydraulic and pneumatic machines (pumps, compressors, motors, cylinders, rotary motors, converters, displacers) in diagrams and drawings of all industries.2. REGULATORY REFERENCES.
This standard uses references to the following standards: GOST 17398-72 Pumps. Terms and Definitions. GOST 17752-81 Volumetric hydraulic drive and pneumatic drive. Terms and definitions. GOST 28567-90 Compressors. Terms and Definitions.3. DEFINITIONS.
This standard uses terms according to GOST 17752, GOST 17398 and GOST 28567.4. BASIC PROVISIONS.
4.1. The designations reflect the purpose (action), method of operation of the devices and external connections.4.2. The designations do not indicate the actual design of the device.4.3. The letters used in the designations represent only letter designations and do not give an idea of the parameters or parameter values.4.4. Unless otherwise stated, symbols may be drawn in any arrangement as long as their meaning is not distorted.4.5. The standard does not establish the dimensions of symbols. 4.6. Designations based on functional characteristics must correspond to those given in Table 1. If it is necessary to reflect the principle of operation, then the designations given in Table 2.4.7 are used. Rules and examples of designations for the relationship between the direction of rotation, the direction of flow of the working fluid and the position of the control device for pumps and motors are given in Appendices A and B.Table 1
|
Name |
Designation |
| 1. Non-regulated pump: - with non-reversible flow | |
| - with reverse flow | |
| 2. Adjustable pump: - with non-reversible flow | |
| - with reverse flow | |
| 3. Adjustable pump with manual control and one direction of rotation |
|
| 4. Pressure-regulated pump with one direction of rotation, adjustable spring and drain (see appendices A and B) |
|
| 5. Metering pump | |
| 6. Multi-outlet pump (for example, a three-outlet adjustable pump with one plugged outlet) |
|
| 7. Unregulated hydraulic motor: - with irreversible flow | |
| - with reverse flow | |
| 8. Hydraulic motor adjustable: - non-reversible flow, indefinite control mechanism, external drainage, one direction of rotation and two shaft ends |
|
| 9. Rotary hydraulic motor | |
| 10. Compressor | |
| 11. Unregulated pneumatic motor: - with irreversible flow | |
| - with reverse flow | |
| 12. Adjustable air motor: - with non-reversible flow | |
| - with reverse flow | |
| 13. Rotary air motor | |
| 14. Unregulated pump-motor: - with the same flow direction | |
| - with any flow direction | |
| 15. Pump-motor adjustable: - with the same flow direction | |
| - with reverse flow direction | |
| - with any direction of flow, with manual control, external drainage and two directions of rotation |
|
| 16. The pump-motor is adjustable, with two directions of rotation, spring centering of the displacement zero, external control and drainage (signal n causes movement in the direction N) (see appendices A and B) |
|
| 17. Volumetric hydraulic transmission: - with an unregulated pump and motor, with one direction of flow and one direction of rotation |
|
| - with adjustable pump, with reversible flow, with two directions of rotation with variable speed |
|
| - with a non-regulated pump and one direction of rotation |
|
| 18. Single-acting cylinder: - piston without specifying the method of rod return, pneumatic |
|
| - piston with spring return, pneumatic |
|
| - piston with spring rod extension, hydraulic |
|
| - plunger | |
| - telescopic with one-sided extension, pneumatic |
|
|
|
|
| 19. Double-acting cylinder: - with one-way rod, hydraulic |
|
| - with double-sided rod, pneumatic |
|
| - telescopic with one-way extension, hydraulic |
|
| - telescopic with two-way extension |
|
| 20. Differential cylinder (the ratio of the piston areas from the rod and non-rod cavities is of paramount importance) |
|
| 21. Double-acting cylinder with supply of working fluid through the rod: - with one-sided rod |
|
| - with double-sided rod |
|
| 22. Double-acting cylinder with constant braking at the end of the stroke: - on the piston side |
|
| - on both sides |
|
| 23. Double-acting cylinder with adjustable end-stroke braking: - piston side |
|
| - on both sides and an area ratio of 2:1 Note – If necessary, the ratio of the annular area of the piston to the area of the piston (area ratio) can be given above the piston designation |
|
| 24. Double-chamber, double-acting cylinder |
|
| 25. Diaphragm cylinder: - single-acting | |
| - double acting | |
| 26. Pneumohydraulic displacer with separator: - translational | |
| - rotational |
|
| 27. Translational converter: - with one type of working medium | |
| 28. Rotary converter: - with one type of working medium |
|
| - with two types of working environment |
|
| 29. Cylinder with built-in mechanical locks |
|
table 2
|
Name |
Designation |
|
1. Hand pump |
|
|
2. Gear pump |
|
|
3. Screw pump |
|
|
4. Vane pump |
|
|
5. Radial piston pump |
|
|
6. Axial piston pump |
|
|
7. Crank pump |
|
|
8. Centrifugal vane pump |
|
|
9. Jet pump: General designation |
|
|
With liquid external flow |
|
|
With external gas flow |
|
|
10. Fan: Centrifugal |
|
APPENDIX A
(recommended)
RULES FOR INDICATING THE DEPENDENCE OF THE DIRECTION OF ROTATION ON THE DIRECTION OF WORKING MEDIUM FLOW AND THE POSITION OF THE CONTROL DEVICE FOR HYDRAULIC AND PNEUMATIC MACHINES.
A.1. The direction of shaft rotation is indicated by a concentric arrow around the main designation of the machine from the power input element to the power output element. For devices with two directions of rotation, only one randomly selected direction is shown. For double shaft devices, the direction is shown at one end of the shaft.A.2. For pumps, the arrow begins at the drive shaft and ends with a point at the outlet flow line.A.3. For motors, the arrow begins at the input flow line and ends with the tip of the arrow at the output shaft.A.4. For pump-motors according to A.2 and A.3.A.5. If necessary, the corresponding position designation of the control device is shown near the tip of the concentric arrow.A.6. If the control characteristics are different for the two directions of rotation, information is shown for both directions.A.7. Line showing control device positions and position designations (e.g. M - Æ - N) are applied perpendicular to the control arrow. The sign Æ indicates the position of zero displacement, the letters M and N indicate the extreme positions of the control device for the maximum displacement. It is preferable to use the same symbols that are marked on the body of the device. The point of intersection of the arrow indicating regulation and perpendicular to the line indicates the “in stock” position (Figure 1). 
Picture 1.
APPENDIX B
(recommended)
EXAMPLES OF INDICATING THE DEPENDENCE OF THE DIRECTION OF ROTATION ON THE DIRECTION OF WORKING MEDIUM FLOW AND POSITIONS OF THE CONTROL DEVICE FOR HYDRAULIC AND PNEUMATIC MACHINES.
Table B.1
|
Name |
Designation |
| 1. Single-function device (motor). The hydraulic motor is unregulated, with one direction of rotation. | |
| 2. Single-function device (machine). The hydraulic machine is unregulated, with two directions of rotation. One direction of rotation is shown, related to the direction of flow. |
|
| 3. Single-function device (pump). The hydraulic pump is adjustable (with a change in working volume in one line), with one direction of rotation. The control device position designation may be omitted and is shown in the illustration for clarity only. |
|
| 4. Single-function device (motor). The hydraulic motor is adjustable (with displacement changing in one direction), with two directions of rotation. One direction of rotation is shown, related to the direction of flow. |
|
| 5. Single-function device (machine). The hydraulic machine is adjustable (with a change in working volume in both directions), with one direction of rotation. The direction of rotation and the corresponding position of the control device related to the direction of flow are shown. |
|
| 6. Single-function device (machine). The hydraulic machine is adjustable (with a change in working volume in both directions), with two directions of rotation. Shown is one direction of rotation and the corresponding position of the control device associated with the direction of flow. |
|
| 7. Pump-motor. The pump-motor is unregulated with two directions of rotation. | |
| 8. Pump-motor. The pump-motor is adjustable (with displacement changing in one direction), with two directions of rotation. One direction of rotation is shown, related to the direction of flow, when operating in pump mode. |
|
| 9. Pump-motor. The pump-motor is adjustable (with displacement changing in both directions), with one direction of rotation. The direction of rotation and the corresponding position of the control device associated with the direction of flow are shown when operating in pump mode. |
|
| 10. Pump-motor. The pump-motor is adjustable (using displacement in both directions, with two directions of rotation. One direction of rotation and the corresponding position of the control device associated with the direction of flow are shown when operating in pump mode. |
|
| 11. Motor. Motor with two directions of rotation: adjustable (with a change in displacement in one line) in one direction of rotation, unregulated in the other direction of rotation. Both possibilities are shown. |
|
A hydraulic diagram is an element of technical documentation that uses symbols to show information about the elements of the hydraulic system and the relationships between them.
According to the ESKD standards, hydraulic circuits are designated in the main inscription code by the letter “G” (pneumatic circuits - by the letter “P”).
As can be seen from the definition, on hydraulic diagram Conventionally, elements are shown that are connected to each other by pipelines - indicated by lines. Therefore, in order to correctly read a hydraulic diagram, you need to know how this or that element is indicated on the diagram. The symbols of the elements are specified in GOST 2.781-96. Study this document and you will be able to find out how the main hydraulic elements are designated.
Designations of hydraulic elements on diagrams
Let's look at the main elements hydraulic circuits.
Pipelines
Pipelines on hydraulic diagrams are shown as solid lines connecting elements. Control lines are usually shown as a dotted line. The directions of fluid movement, if necessary, can be indicated by arrows. Lines are often indicated on hydraulic diagrams by the letter P denotes pressure line, T - drain, X - control, l - drain.
The connection of lines is shown by a dot, and if the lines intersect on the diagram, but are not connected, the intersection is indicated by an arc.
Tank
A hydraulic tank is an important element that stores hydraulic fluid. A tank connected to the atmosphere is shown on the hydraulic diagram as follows.
A closed tank, or container, such as a hydraulic accumulator, is shown as a closed loop.
In the filter designation, the diamond symbolizes the housing, and the dashed line symbolizes the filter material or filter element.
Pump
On hydraulic diagrams, several types of pump designations are used, depending on their types.
Centrifugal pumps are usually depicted as a circle, with a suction line connected to the center and a discharge line to the perimeter of the circle:
Volumetric(gear, piston, plate, etc.) pumps denoted by a circle with an arrow triangle indicating the direction of fluid flow.
If two arrows are shown on the pump, then this unit is reversible and can pump liquid in both directions.
If the designation is crossed out by an arrow, it means the pump is adjustable, for example, the volume of the working chamber can change.
Hydraulic motor
The designation of the hydraulic motor is similar to the designation of the pump, only the triangle-arrow is rotated. In this case, the arrow shows the direction of fluid supply to the gyromotor.
To designate a hydraulic motor, the same rules apply as for designating a pump: reversibility is shown by two triangular arrows, the possibility of regulation by a diagonal arrow.
The figure below shows an adjustable reversible pump-motor.
Hydraulic cylinder
Hydraulic cylinder- one of the most common hydraulic motors, which can be read on almost any hydraulic diagram. The design features of a hydraulic cylinder are usually reflected on a hydraulic diagram; let’s look at a few examples.
The double-acting cylinder has connections to the piston and rod chambers.
A plunger hydraulic cylinder is depicted on hydraulic diagrams as follows.
The schematic diagram of a telescopic hydraulic cylinder is shown in the figure.
Distributor
Distributor on hydraulic circuit is shown by a set of square windows, each of which corresponds to a specific spool position (position). If the distributor is two-position, then in the diagram it will consist of two square windows, three-position - of three. Inside each window it is shown how the lines are connected in a given position.
Let's look at an example.
The figure shows a four-line (four lines A, B, P, T are connected to the distributor), three position (three windows) distributor. The diagram shows the neutral position of the distributor spool, in this case it is in the central position (the lines are connected to the central window). Also, the diagram shows how the hydraulic lines are connected to each other, in the example under consideration in the neutral position lines P and T are connected to each other, A and B are plugged.
As you know, a distributor can connect different lines by switching, this is shown in the hydraulic diagram.
Consider the left window, which shows that by switching the distributor will connect lines P and B, A and T. This conclusion can be made by virtually moving the distributor to the right.
The remaining position is shown in the right window, lines P and A, B and T are connected.
The following video shows the operating principle of the hydraulic distributor.
Understanding the principle of operation of the distributor, you can easily read hydraulic diagrams that include this element.
Control devices
In order to control an element, for example a distributor, you need to influence it in some way.
The following symbols are shown: manual, mechanical, hydraulic, pneumatic, electromagnetic and spring return.
These elements can be arranged in different ways.
The following picture shows four-line, two-position valve, with electromagnetic control and spring return.
Valve
Valves in hydraulics are usually shown as a square, which conventionally shows the behavior of the elements when exposed.
Safety valve
The figure shows the symbol of the safety valve. The diagram shows that as soon as the pressure in the control line (shown by the dotted line) exceeds the setting of the adjustable spring, the arrow will move to the side and the valve will open.
Pressure reducing valve
Also quite common in hydraulic and pneumatic systems. pressure reducing valves, the control pressure in such valves is the pressure in the outlet line (at the outlet of the pressure reducing valve).
An example of a pressure reducing valve designation is shown in the following figure.
Reverse valve
The purpose of a check valve is to allow fluid to flow in one direction and block its movement in the other. This is reflected in the diagram. In this case, when flowing from top to bottom, the ball (circle) will move away from the saddle, indicated by two lines. And when liquid is supplied from below - upward, the ball will be pressed against the seat and will not allow the fluid to flow in this direction.
Diagrams of a check valve often show a spring under the ball, providing preload.
Throttle - adjustable hydraulic resistance.
Hydraulic resistance or a non-adjustable throttle is depicted in the diagrams by two curved lines. The possibility of adjustment is, as usual, indicated by the addition of an arrow, so an adjustable throttle will be indicated as follows:
Measuring devices
The following measuring instruments are most often used in hydraulics: pressure gauge, flow meter, level indicator, the designation of these devices is shown below.
Pressure switch
This device switches the contact when a certain pressure level is reached. This level is determined by the spring setting. All this is reflected in the pressure switch diagram, which, although a little more complicated than those presented earlier, is not so difficult to read.
The hydraulic line is connected to the shaded triangle. The switching contact and adjustable spring are also present in the diagram.
Combining elements
Quite often in hydraulics, one block or apparatus contains several simple elements, for example a valve and a throttle; for ease of understanding, on a hydraulic diagram, the elements included in one apparatus are outlined with a dashed line.
In order to correctly read a hydraulic diagram, you need to know the symbols of the elements, understand the operating principles and purpose of hydraulic equipment, be able to step by step understand the features of individual sections, and correctly combine them into a single hydraulic system.
To correctly design a hydraulic circuit, you need to draw up a list of elements in accordance with the standard.Shown below hydraulic drive diagram, allowing you to move the hydraulic cylinder rod, with the ability to charge the hydraulic accumulator.
Why do you need a hydraulic diagram?
A hydraulic diagram consists of simple graphic symbols of components, controls and connections. Drawing details has become more convenient, and symbols are more universal. Therefore, with training, everyone can understand the symbols of the system. A hydraulic diagram is usually preferred for explaining the device and troubleshooting.
The two pictures show that the top one is the hydraulic circuit of the bottom picture. When comparing the two drawings, note that the hydraulic diagram does not show the design features or the relative positions of the circuit components. The purpose of a hydraulic diagram is to show the purpose of components, connections and flow lines.
Pump symbols
The main pump symbol is a circle with a black triangle pointing outward from the center. The pressure line comes out of the top of the triangle, the suction line is located opposite.
Thus, the triangle shows the direction of flow.
This symbol indicates a constant flow pump.
The variable displacement pump is indicated in the figure with an arrow passing through the circle at an angle of 15°
Drive symbols
Motor symbol
The symbol of the motor is a circle with black triangles, but the top of the triangle is directed towards the center of the circle to show that the motor receives pressure energy.
Two triangles are used to indicate a variable flux motor.
A variable output motor with a change in flow direction is indicated by an arrow passing through a circle at an angle of 45°
Cylinder symbols
The cylinder symbol represents a rectangle representing the cylinder body (cylinder) with a line symbol representing the piston and rod. The symbol indicates the position of the cylinder rod in a certain position.
Double acting cylinder
This symbol has a closed cylinder and has two matching lines, indicated by lines in the figure.
Single acting cylinder
Only one line is connected to single-acting cylinders, indicated in the figure by a line; the opposite side of the figure is open.
Flow direction
The direction of flow to and from the actuator (change-of-flow motor or double-acting cylinder) is depicted depending on which line the actuator fits into. An arrow is used to indicate flow.
Valve symbols - 1
1) Distribution valve
The basic symbol of a control valve is a square with outlet holes and an arrow inside to indicate the direction of flow. Typically, a control valve is controlled by a balance of pressure and spring, so in the diagram we show a spring on one side and a pilot line on the other side.
Normally closed valve
Typically a closed valve, such as a relief valve, is indicated by a counterweight arrow from the ports directly to the pilot pressure line. This shows that the spring is holding the valve closed until the pressure overcomes the resistance of the spring. We mentally draw an arrow connecting the flow from the inlet to the outlet as the pressure increases to overcome the spring tension.
Safety valve
The illustration shows a safety valve with the symbol usually closed, connected between the pressure line and the tank. When the pressure in the system exceeds the spring tension, the oil goes into the tank.
Note:
The symbol does not indicate whether it is a simple or complex safety valve. This is important for indicating their functions in the circuit.
The working process:
(a) The valve always remains closed
(b) When pressure appears in the main circuit, the same pressure acts on the valve through the pilot line and when this pressure overcomes the resistance of the spring, the valve opens and oil flows into the tank, thereby reducing the pressure in the main circuit.
Normally open valve
When the arrow connects the inlet and outlet ports, the valve is normally open. The valve closes when the pressure overcomes the resistance of the spring.
The pressure reducing valve is usually open and is identified as shown in the figure below. The release pressure is shown opposite the spring to establish or interrupt the flow when the value to compress the spring is reached.
The working process:
(a) Oil flows from the pump to the main circuit and A
(b) When the valve outlet pressure becomes higher than the set pressure, the oil flow from the pump is stopped and the pressure in circuit A is maintained. It is not affected by the pressure of the main circuit.
(c) When the pressure in circuit A drops, the valve returns to state (a). Therefore, the pressure in circuit A is maintained because conditions (a) and (b) are protected.
Valve symbols - 2
2) FLOW DISTRIBUTION VALVE
Check valve
A check valve opens to allow oil to flow in one direction and closes to prevent oil from flowing in the opposite direction.
Spool valve
The control spool valve symbol uses a complex closed system that has a separate rectangle for each position.
Four-hole valve
Typically a four-hole valve will have two compartments if the valve has two positions, or three compartments if the valve has a center position.
Lever control symbols
Lever control symbols represent a lever, pedal, mechanical controls or pilot line located on the edge of the compartment.
Valve symbols - 3
3) HITACHI FOUR FLOW DIRECTION VALVE
Hitachi 4-Way Valve Symbols are similar to the 4-Way symbol, but with added connections and flow channels to show the bypass port.
Symbols for cylinder and motor spools are shown in the figure. Please remember that these symbols only show spool valves. The control valve block also shows the relief valves and connections to the body.
4) REducer VALVE
The pressure reducing valve symbol is shown in the figure and includes a normally closed valve with a built-in check valve.
The working process:
The pressure reducing valve is installed on the winch motor of the hydraulic crane.
(a) When the load is lowered, back pressure is created because there is a check valve.
(b) The pressure in the pressure line increases, the pilot line opens the valve to direct the flow of oil from the engine through the valve into the return line. This ensures protection against free fall of the load.
When developing and drawing up projects and schemes of water supply and sewerage in paper and electronic documents, drawings and accompanying applications, symbols are used that characterize the parameters of devices, mechanisms, parts and elements, as well as alphabetic and numeric symbols for special purposes. For example, the designation of a pump on a water supply and sewerage diagram must necessarily be present in the drawings of not only industrial-scale construction projects, but also in individual construction projects, as well as the symbols of pipelines and other components and mechanisms of engineering communications. All these symbols, symbols and icons are described in detail in GOST 21.205-93, and their use is built into computer programs for creating drawings of water supply and sewerage systems, such as AutoCAD, FreeCAD, T-FLEX CAD, DraftSight Free CAD", "LibreCAD" and others, working in Computer-Aided Design and Drawing (CAD) standards.
Why are drawings and projects of water supply and sewerage drawn up?
All construction sites - industrial, residential or strategic buildings are, to one degree or another, equipped with sanitary systems that have some common characteristics and functions. Such systems are not isolated - they consist of a complex of engineering and communication circuits and components, such as hot water supply and hot water supply, sewer lines, centralized gas supply, garbage chute lines, storm sewer and snow retention systems, heating units, electrical and communications communications.
With so many complex systems, they all must be brought to a single standard to minimize the risk of emergency situations and other unplanned malfunctions. The most important engineering systems are sewerage and water supply, therefore their layout must be clearly reflected in drawings and network diagrams, in compliance with all designations accepted by standards. Only by observing the conventions established by GOST can you launch a facility that complies with the rules of livability and comfortable operation.
- Water supply in a residential area in general and individually in each apartment has its own role - these systems ensure not only the full functioning of residents, but also preserve their health. Therefore, when drawing up project documentation, one cannot allow the slightest deviation in calculations and drawings, since this will certainly affect the lifestyle, the health of people, and the technical condition of the systems in the future.
- The sewer removes waste dirty water, domestic wastewater and crushed solid human waste from residential premises; the garbage chute also performs the same function. As in water supply, in the sewerage system the first and necessary unit is a pump. Considering the aggressiveness of the environment and the constituent components of the wastewater, the system must be as reliable as possible throughout the entire period of operation, which means that the very first steps - drawing up drawings and documentation - must be taken responsibly.
All sewer drains, pipeline and gas pipeline taps on diagrams, water supply and sewerage systems have their own symbols and designation marks in project drawings, which should be displayed the same everywhere. Due to the complexity of drawing up such projects, it is recommended to entrust such work to professionals so that not only the correct symbols and designations of water supply systems, pumps, valves, sewers, pipes and shut-off valves on the diagram are observed, but also their parameters are calculated for long-term maintenance-free operation.
Features of schematic symbols
Before drawing up the final version of the project, preliminary drawings are developed that take into account the specific operating conditions of the equipment in a particular room. The draft design will take into account the geographical and technical features of the building, the number of residential and technical premises, the location and direction of water input and output, etc. After preliminary drawings and design documents have been drawn up for each room of the house, they are combined into one final design.
But on each drawing, on each diagram, only generally accepted symbols and symbols should be used so that any builder, architect or engineer can correctly read the drawing and accurately perform their part of the work.
The use of other conventional icons, symbols and designations in construction documentation is strictly prohibited by GOST 21.205-93. There are several hundred established and approved designations, so let’s look at their use using the example of pumps - circulation pumps, pumping pumps, and others.
Symbols of pumps are shown in the table:
Based on the symbols approved by GOST 21.205-93, all of the above programs for drawing up drawings and 2-D or 3-D visualization of projects work.
When developing a sewer or hot water supply project, in heating and other pipeline diagrams, developers indicate with symbols and other symbols the locations of hot or cold water connections, inlet and outlet of wastewater, the location of plumbing fixtures and other equipment. The complexity of the circuit and installed equipment depends largely on the area and functional purpose of the room, therefore, even for identical rooms, wiring and connection diagrams will always be different. When drawing up projects and drawings of hot water supply, cold water and sewerage systems, only generally accepted special symbols are used. Discrepancies in the documentation are unacceptable, and it is not permitted to independently change the designations in preliminary and final documents.
Symbols of water supply and sewerage in the drawing
Working data on the properties and parameters of the water supply and sewerage system in the diagrams and drawings of pipelines of utility networks are entered into the design documentation by symbols in letters and numbers.
Any water supply network is designated by the alphanumeric symbols “B0”, the pipeline for domestic and drinking needs is designated by the symbols “B1”, water supply communications for fire-fighting systems are designated by the symbols “B2”, pipes for supplying process water are designated as “B4”. That is, all designations that have the symbol “B” at the beginning refer to the water supply of the facility.
General sewerage is designated by the Cyrillic symbol “K”, sewerage for domestic wastewater is designated by the symbol set “K1”, storm drainage is designated by “K2”, and wastewater disposal on an industrial scale is designated by the symbols “K3”.
In plumbing and sewer diagrams, along with lines, special alphanumeric designations and symbols are used in the drawing process. All symbols are unexplained, with the exception of specific industry symbols in the diagram. Such designations (for example, a non-standard valve) are deciphered by indicating a link to a detailed description of the element. Not all symbols regulated by the standard must always be used in design, but some are required, since water supply, sewerage, and heating systems are installed in all residential buildings. This could be a pump or valve in the drawing, the designation of a coarse or fine filter, the presence of a heat exchanger or manual (automatic) valves in the diagram.
Also, on the diagram of the utility lines of a house, there are often lines like a dotted line with a dot, or straight and dotted lines. These are designations for domestic wastewater, stormwater and mixed sewerage systems.
In addition, diagrams and drawings may contain elements and symbols with long or short, complemented by various symbols and elements: circles, cylindrical symbols, squares or rectangles, triangles or perpendicular segments of thin lines. All these symbols and designations have different meanings: they can indicate a sewer, the end of a pipe, a damper embedded in the route, etc. A circle and a letter symbol inside a circle means an oil trap, a grease trap, a fuel flap, a mud trap, etc. If there is no symbol in the circle, then such a designation indicates the presence of a sump tank in the diagram.
Special symbols on project plans also exist to indicate plumbing fixtures and other household equipment. The state standard of 1993 No. 21.205 provides for such designations as a shower stall with a hose and a sprayer, and sinks with mixer taps, and bathtubs themselves, and toilets with different types of water flush. For different devices, even for the same purpose, there are different designations, symbols and icons. These can also be conventional drawings, in the lines of which you can immediately guess what equipment is indicated on the project drawing.
When developing design documentation for the construction of a house, designers take into account many more auxiliary and secondary conditions: it is necessary to designate not only the main components, but also the parts that ensure their operation - heating main pipes, water supply or sewerage, valves and filters, traps and shut-off valves, fittings and turns. Such detailed information will help you read the drawing faster and more clearly, and implement it in practice without errors. Letters, numbers, pictures, geometric shapes and other symbols are also used to indicate additional information.
In the drawings of the building project, it is necessary to display a diagram of the wiring of engineering and technical communications, such as the supply of hot water and cold water, sewerage and heating, the parameters of sewer, inspection and collector wells and other technical information that is recommended to be used in the process of work. It is not enough to rely only on key data - if additional information is used, the project will be implemented with a long-term operational perspective, without accidents and unplanned repairs. The volume of design work is quite large for self-taught builders, so hiring professional designers will be the only right decision.
All designations and forms of numbers, Latin, Cyrillic and graphic letters, geometric figures and symbols must be used only for their intended purpose, without distorting the display on the diagram. It is forbidden to use images and designations of elements not regulated by GOST and SNiP in drawings and diagrams of sewerage and water supply systems. Loss of the correct perception of the designation at any stage of construction or installation will break the entire scheme, which will lead to wasted time and labor costs.
Correctly used symbols, letters, geometric shapes and symbols are a guarantee of correct reading of the design documentation, and therefore the correct execution of construction and installation work at the site. By complying with all GOST requirements, you will achieve efficient operation of all engineering networks, which means long-term and uninterrupted operation.
