Fluid Power and Electrical Graphic Symbols Caterpillar

Note: Use this module as a basic reference guide for graphic symbols. Do not use this module as a comprehensive reference guide.

Line Identification

Illustration 1	g01387054
(A) Pressure line (B) Pilot/Load sensing pressure line (C) Drain/Return line (D) Component line (E) Attachment line (F) Air Line

Valve Envelopes

Illustration 2	g01345717
(G) One position (H) Two-position (J) Three-position

Fluid Storage Reservoirs

Illustration 3	g01345911
(K) Vented (L) Pressurized (M) Return above fluid level (N) Return below fluid level

Techniques For Crossing and Joining Lines

Illustration 4	g01819313
(P) Line crossing (R) Lines joining

Valve Ports

Illustration 5	g01353004
(S) Two-way (T) Three-way (U) Four way

Fluid Conditioners

Illustration 6	g01353011
(V) Filter or strainer

Illustration 7	g01386985
Separators (W) Manual drain (X) Automatic drain

Illustration 8	g01386986
Filter separators (Y) Manual drain (Z) Automatic drain

Basic Component Symbols

Illustration 9	g01819355
(AA) Pump or motor (AB) Fluid conditioner (AC) Control valves (AD) Spring (AE) Restriction (AF) Line restriction (AG) Two-section pump (1) Main (2) Auxiliary (AH) Adjustable spring (AJ) Line restriction (variable) (AK) Variability

Supplemental Component Symbols

Illustration 10	g01819393
Energy triangles (AL) Hydraulic (AM) Pneumatic

Illustration 11	g01819413
Measurement (AN) Pressure (AP) Temperature (AR) Pressure tap (AS) Flow

Illustration 12	g01819434
(AT) Unidirectional (AU) Bidirectional

Pilot Control Symbols

Illustration 13	g01820233
Released pressure (AV) External return (AW) Internal return

Illustration 14	g01820235
Remote supply pressure (AX) Simplified (AY) Complete (AZ) Internal pressure supply

Manual Control Symbols

Illustration 15	g01820255
(BA) Push-pull lever (BB) General manual (BC) Pedal (BD) Push button (BE) Spring (BF) Manual shutoff

Accumulators

Illustration 16	g01353246
(BG) Spring loaded (BH) Gas charged

Combination Controls

Illustration 17	g01820273
(BJ) Solenoid or manual (BK) Solenoid and pilot (BL) Solenoid, pilot, or manual

Illustration 18	g01629934
(CP) Connector (Mechanical Stop)

Electrical Controls

Illustration 19	g01353280
(BM) Solenoid

Miscellaneous Controls

Illustration 20	g01820293
(BN) Servo (BP) Thermal (BR) Detent

Hydraulic, Pneumatic Cylinders

Illustration 21	g01353333
Single acting

Illustration 22	g01387001
Double acting (BS) Single end rod (BT) Double end rod

Hydraulic Pumps

Illustration 23	g01820296
Fixed displacement (BU) Unidirectional (BV) Bidirectional

Illustration 24	g01820298
Variable displacement (BW) Unidirectional (BX) Bidirectional simplified (BY) Bidirectional complete

Hydraulic Motors

Illustration 25	g01820313
Fixed displacement (BZ) Unidirectional (CA) Bidirectional

Illustration 26	g01820314
Variable displacement (CB) Unidirectional (CC) Bidirectional

Shutoff Valves

Illustration 27	g01820321
(CD) Basic symbols (CE) Manual shutoff valve

One-Way Check Valves

Illustration 28	g01353434
(CF) Basic symbol (CG) Spring loaded

Internal Passageways

Illustration 29	g01820338
(CH) Infinite position (3) Flow in one direction (CJ) Two-position (4) Flow allowed in either direction (CK) Three-position (5) Parallel flow (6) Cross flow

Pressure Differential Valve

Illustration 30	g01358506
(7) Inlet (X psi) (8) Outlet (Y psi)

Control Valves

Illustration 31	g01820466
(CL) Normal position (CM) Shifted position (CN) Infinite Position

Simple Single Function Circuit

Illustration 32	g01358688
(9) 45 L/min (12 US gpm) (10) 17000 kPa (2500 psi) (11) 450 kPa (65 psi)

Illustration 33	g01358901
(12) Three-position four-way open centered motor spool and pilot controlled directional controlled valve (13) Combination crossover relief valve and makeup valve ( 24000 kPa (3500 psi)) (14) Bidirectional motor (15) Main system relief valve (16) Pressure reducing pilot controlled valves (17) Check valve (18) Gas charged accumulator (19) Main pump motor ( 115 L/min (30 us gpm)) (20) Pilot pump motor ( 19 L/min (5 us gpm)) (21) Pilot filter and bypass valve (22) Pilot relief valve ( 2250 kPa (325 psi) (23) Two positioned two-way pilot system disconnect valve (24) Tank