4500 Series Pilot-Actuated Pressure Relief Valve

Applicable media: gases, liquids, etc.
Size range: 1" × 2" to 8" × 10".
Pressure range: 0.1 MPa (g) to 42 MPa (g).
Temperature range: -196 to 260°C.
Materials: carbon steel, stainless steel, copper, Monel alloy, etc.
Optionally: test rod, online safety valve inspection.

Demand consultation

4500 Series Pilot-Actuated Pressure Relief Valve

Product Overview
Features & Benefits
Specifications
Downloads

Product Overview

The Model 4500 pilot-operated pressure relief valve controls valve opening/closing through system pressure without requiring additional external force, enabling the system operating pressure to approach the set pressure more closely than standard spring-loaded pressure relief valves. It complies with API 526 (Chinese National Standard GB/T 28778) specifications for pilot-operated safety valves regarding operating pressure/temperature range and dimensions, with each valve body size featuring multiple flow channel areas.

Features & Benefits

Working Pressure Of The Closed System

The system operating pressure of a pilot-operated safety valve can approach the set pressure more closely, whereas a standard spring-loaded safety valve cannot achieve this.
Resistant To High Inlet Pressure Loss

The remote sensing pilot device adapts to high inlet pressure losses caused by complex inlet pipeline systems, ensuring reliable, fault-free operation.
Differential Pressure Setting

The pilot valve operates rapidly with no delay between its opening and that of the main valve. In contrast, the regulating valve exhibits an inherent delay of approximately 2%. This ensures that the pilot valve does not leak when system pressure approaches the set value.
Integrated Pilot Filter

The pilot-operated filter features an integrated design.
Stainless Steel Material

The pilot valve, top cover, valve stem and accessories, piston, and nozzle are all manufactured from stainless steel, meaning all components in contact with the medium are constructed from this material. This reduces the risk of oxide contamination on the seals, thereby extending their service life.
Back Pressure Resistance Capability

The pilot valve maintains full lift under high back pressure. Unlike spring-loaded valves, which require differential pressure setting or additional balancing bellows for this function.
Soft Sealing Valve Seat

The pilot valve employs a soft-sealed valve seat design to achieve optimal sealing performance. It offers material options suitable for various operating conditions. By reducing the need for valve seat grinding, the maintenance process becomes simpler.
Enhanced Valve Seat Sealing Performance

The main valve employs a piston-driven mechanism. The piston area exceeds the valve seat opening area by more than 30%. This ensures that under all pressure conditions (up to the set point), the valve seat closing force is consistently at least 30% greater than the valve seat opening force. Consequently, this achieves more efficient valve seat sealing performance and effectively reduces the risk of valve seat leakage. When the system pressure is zero, the spring-loaded valve generates maximum seat clamping force. As the system pressure approaches the set value, the upward opening force of the valve approaches the closing force generated by the spring, resulting in nearly zero clamping force and potentially causing seat leakage. The pilot valve featuring a 30% differential pressure piston design maintains 30% seat clamping force near the set value, ensuring optimal seat sealing performance.

Specifications

Main Components and Materials

Order Number	Name	Carbon Steel	Stainless Steel	Order Number	Name	Carbon Steel	Stainless Steel
1	Valve body	WCB	CF3M	9	Hex nut	8Level	A4-70
2	Disc	304	316L	10	Pipe fitting	304	316L
3	O molding ring	Fluorinerubber	Fluorinerubber	11	Collar nut	304	316L
4	Guide sleeve	304	316L	12	Carriage clamp	304	316L
5	Hex bolts	304	316L	13	Take over control	304	316L
6	Spring	50CrV	304	14	Pilotvalve	304	316L
7	Cover lid	20#	316L	15	Supporting plate	20#	20#
8	Isometric double-ended stud	8.8Level	A4-70	16	Hex bolts	8Level	A4-70

*The content is for reference only. For further inquiries, please contact us.

Size

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
1D2	150Lb	150Lb	Carbon steel	-	2	1.2	114	105
	300Lb			-	5.2	4.2		111
	600Lb			-	10.4	8.4		111
	900Lb	300Lb		-	15.6	12.6	121	125
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1 1/2D2	150Lb	150Lb		-	2	1.2		124
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	140	149
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1D2	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	114	105
	300Lb			5	5	3.4		111
	600Lb			10.1	10.1	6.7		111
	900Lb	300Lb		15.2	15.2	10	121	125
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28
1 1/2D2	150Lb	150Lb		1.9	1.9	1.2		124
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	140	149
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
1E2	150Lb	150Lb	Carbon steel	-	2	1.2	114	105
	300Lb			-	5.2	4.2		111
	600Lb			-	10.4	8.4		111
	900Lb	300Lb		-	15.6	12.6	121	125
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1 1/2E2	150Lb	150Lb		-	2	1.2		124
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	140	149
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1E2	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	114	105
	300Lb			5	5	3.4		111
	600Lb			10.1	10.1	6.7		111
	900Lb	300Lb		15.2	15.2	10	121	125
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28
1 1/2E2	150Lb	150Lb		1.9	1.9	1.2		124
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	140	149
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
1F2	150Lb	150Lb	Carbon steel	-	2	1.2	114	105
	300Lb			-	5.2	4.2		111
	600Lb			-	10.4	8.4		111
	900Lb	300Lb		-	15.6	12.6	121	125
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1 1/2F2	150Lb	150Lb		-	2	1.2		124
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	140	149
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
1F2	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	114	105
	300Lb			5	5	3.4		111
	600Lb			10.1	10.1	6.7		111
	900Lb	300Lb		15.2	15.2	10	121	125
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28
1 1/2F2	150Lb	150Lb		1.9	1.9	1.2		124
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	140	149
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
1 1/2G3	150Lb	150Lb	Carbon steel	-	2	1.2	124	130
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	171	162
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
2G3	150Lb	150Lb		-	2	1.2	124	137
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	171	167
	1500Lb			-	26.3	21		167
	2500Lb			-	43.4	35		178
1 1/2G3	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	124	130
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	171	162
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28
2G3	150Lb	150Lb		1.9	1.9	1.2	124	137
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	171	167
	1500Lb			25.3	25.3	16.8		167
	2500Lb			42.2	42.2	28		178

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
1 1/2H3	150Lb	150Lb	Carbon steel	-	2	1.2	124	130
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	171	162
	1500Lb			-	26.3	21
	2500Lb			-	43.4	35
2H3	150Lb	150Lb		-	2	1.2	124	137
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	171	167
	1500Lb			-	26.3	21		167
	2500Lb			-	43.4	35		178
1 1/2H3	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	124	130
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	171	162
	1500Lb			25.3	25.3	16.8
	2500Lb			42.2	42.2	28
2H3	150Lb	150Lb		1.9	1.9	1.2	124	137
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	171	167
	1500Lb			25.3	25.3	16.8		167
	2500Lb			42.2	42.2	28		178

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
2J3	150Lb	150Lb	Carbon steel	-	2	1.2	124	137
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	171	167
	1500Lb			-	25.1	21		167
	2500Lb			-	25.1	25.1		178
3J4	150Lb	150Lb		-	2	1.2	162	156
	300Lb			-	5.2	4.2		156
	600Lb			-	10.4	8.4		162
	900Lb	300Lb		-	15.6	12.6	181	191
	1500Lb	300Lb		-	26.3	21	181	191
2J3	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	124	137
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	171	167
	1500Lb			24.4	24.4	16.8		167
	2500Lb			24.4	24.4	24.4		178
3J4	150Lb	150Lb		1.9	1.9	1.2	162	156
	300Lb			5	5	3.4		156
	600Lb			10.1	10.1	6.7		162
	900Lb	300Lb		15.2	15.2	10	181	191
	1500Lb	300Lb		25.3	25.3	16.8	181	191

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
3K4	150Lb	150Lb	Carbon steel	–	2	1.2	162	156
	300Lb			–	5.2	4.2		156
	600Lb			–	10.4	8.4		162
	900Lb	300Lb		–	15.6	12.6	181	191
	1500Lb	300Lb		–	26.3	21	181	191
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	162	156
	300Lb			5	5	3.4		156
	600Lb			10.1	10.1	6.7		162
	900Lb	300Lb		15.2	15.2	10	181	191
	1500Lb	300Lb		25.3	25.3	16.8	181	191

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
3L4	150Lb	150Lb	Carbon steel	-	2	1.2	162	156
	300Lb			-	5.2	4.2		156
	600Lb			-	8.5	8.4		162
	900Lb	300Lb		-	15.6	12.6	181	191
	1500Lb	300Lb		-	20	20	181	191
4L6	150Lb	150Lb		-	2	1.2	210	197
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	233	249
	1500Lb	300Lb		-	26.3	21	233	249
3L4	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	162	156
	300Lb			5	5	3.4		156
	600Lb			8.2	8.2	6.7		162
	900Lb	300Lb		15.2	15.2	10	181	191
	1500Lb	300Lb		19.4	19.4	16.8	181	191
4L6	150Lb	150Lb		1.9	1.9	1.2	210	197
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	233	249
	1500Lb	300Lb		25.3	25.3	16.8	233	249

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
4M6	150Lb	150Lb	Carbon steel	-	2	1.2	210	197
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	233	249
	1500Lb	300Lb		-	26.3	21	233	249
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	210	197
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	233	249
	1500Lb	300Lb		25.3	25.3	16.8	233	249

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
4N6	150Lb	150Lb	Carbon steel	-	2	1.2	210	197
	300Lb			-	5.2	4.2
	600Lb			-	10.4	8.4
	900Lb	300Lb		-	15.6	12.6	233	249
	1500Lb	300Lb		-	26.3	21	233	249
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	210	197
	300Lb			5	5	3.4
	600Lb			10.1	10.1	6.7
	900Lb	300Lb		15.2	15.2	10	233	249
	1500Lb	300Lb		25.3	25.3	16.8	233	249

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
4P6	150Lb	150Lb	Carbon steel	-	2	1.2	210	197
	300Lb			-	5.2	4.2
	600Lb			-	9	8.4
	600Lb	300Lb		-	10.4	8.4	233	249
	900Lb			-	15.6	12.6
	1500Lb			-	21.2	21
	1500Lb	600Lb		-	25.3	21	264
4P6	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	210	197
	300Lb	150Lb		5	5	3.4	210	197
	600Lb	300Lb		10.1	10.1	6.7	233	249
	900Lb	300Lb		15.2	15.2	10	233
	1500Lb	600Lb		25.3	25.3	16.8	264

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
6Q8	150Lb	150Lb	Carbon steel	-	2	1.2	241	240
	300Lb			-	5.2	4.2		240
	600Lb			-	9.1	8.4		246
	600Lb	300Lb		-	10.4	8.4	265	246
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	241	240
	300Lb			5	5	3.4		240
	600Lb			10.1	8.8	6.7		246
	600Lb	300Lb		15.2	10.1	6.7	265	246

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
6R8	150Lb	150Lb	Carbon steel	-	2	1.2	241	240
	300Lb			-	5.2	4.2		240
	600Lb			-	6.3	6.3		246
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	241	240
	300Lb			5	5	3.4		240
	600Lb			6.1	6.1	6.1		246

Valve Size ( Import× Flow Channel Code × Export )	Nominal Pressure		Maximum Set Pressure /Mpa				Structure Length/Mm
Valve Size ( Import× Flow Channel Code × Export )	Import	Export	Valve Body Material	-268℃~-29℃	-29℃~38℃	38℃~260℃	L	L1
8T10	150Lb	150Lb	Carbon steel	-	2	1.2	279	276
	300Lb			-	5.2	4.2		276
	600Lb			-	6.2	6.2		297
	150Lb	150Lb	Stainless steel	1.9	1.9	1.2	279	276
	300Lb			5	5	3.4		276
	600Lb			6.1	6	6		297