Instrumentation MP / HP
Instrumentation MP / HP – general information
There are several types of high pressure connections, but most of them originate in the Autoclave standard. In MP, HP and HP Waterblast connections, the end of the tube is coned to 58°-59° angle, whereas the seat inside the body is at 60° angle. Close contact of these cones produces a metal-to-metal seal. HP Waterblast derives from HP system.
MP/HP fittings make a unique group of tube and hose connections: type MP intended for working pressure up to 1380 bar (20000 PSI) and type HP up to 4140 bar (60000 PSI). The end of the tube is coned to 58º-59º and cut with a left-hand thread. The collar is screwed onto the left-hand thread. The externally threaded nut is screwed into the body and presses the coned tube end against the seat in the body. This connection is typical to MP/HP fittings, which include: straight connectors, elbows, tees and crosses, as well as valves: needle valves, ball valves and check valves. Thus, they are used for building entire UHP systems. Some elements (ball and check valves) are for slightly lower pressures (690 bar, 1034 bar), also with NPT thread.
MP – (medium pressure) pressure up to 1380 bar (20 000 PSI)
HP – (high pressure) pressure up to 1140 bar (60 000 PSI)
1 – UHP tube; 2 – gland nut; 3 – collar; 4 – connector; 5 – SPIR STAR hose; 6 – weep hole
α = 58º (tube end); α = 60º (seat);
In MP connection – the gland nut rests against the collar screwed on the end of the tube, while in HP connection, the collar sits inside the gland nut.
First, slide a gland nut onto a correctly finished tube (58° cone + left-hand thread of correct length), and then screw a collar on. The collar is in the right position, if 1 ÷ 2 full threads extend beyond the collar at the coned end. Place the tube, prepared in this way, in the body, tighten it by hand, and then, using a torque spanner, tighten it with a torque recommended for given working pressure and tube size values.
Use anti-seize thread paste for MP/HP connections.
UHP needle valves
High quality UHP valves with MP and HP connections, made of AISI 316 stainless steel (knob – aluminium, optionally stainless steel). Stem (needle) in 17-4 PH steel. Gland packing in glass fibre reinforced PTFE. Working pressure range from -17°C to +315°C. For temperatures above 200°C, working pressure depends on temperature – contact Tubes International. Flow in both directions is possible. The valve is equipped with a non-rotating stem, the valve opens fully after only 4.5 turns (3 turns for 3/4” and 1”). Special option – opens with 1.75 turns. Fitted with weep holes on both sides for leak control. Mounting holes for screws in standard configuration. Marking on the valve ensures full traceability. Valves available with pneumatic actuation instead of manual actuation and, on special request, valves according to NACE MR-01-75.
UHP ball valves
High quality trunnion ball valves for working pressure up to 20000 psi (1380 bar) with NPT female connections and MP connections, made of AISI 316 steel. PEEK and Viton sealing. Mounting holes for screws in standard configuration. Marking on the valve ensures full traceability. Working temperature range from -28°C to +204°C. Note: not suitable for molecular gases (helium, hydrogen).
Check valves
Check valves prevent backflow and possible damage to the pressure system. Made of AISI 316 stainless steel, with NPT, MP and HP connections. Nominal opening pressure is 15 psi (1 bar). Working temperature range for NPT: 18°C to +204°C. Working temperature range for MP/HP: soft seat version from 45°C to +204°C, metal seat version (ball seat) from 80°C to +260°C. Stem packing made of PEEK. Valves according to NACE MR-01-75 also available.
List of products:
MP/HP connection fittings
UHP needle valves
UHP ball valves
